HT30XC Instruction Manual Issue 14

Computer Controlled Heat Exchanger Service Unit

Instruction Manual

HT30XC ISSUE 14 June 2010

Table of Contents Copyright and Trademarks ...................................................................................... 1 General Overview ....................................................................................................... 2 Equipment Diagrams................................................................................................... 3 Important Safety Information....................................................................................... 4 Introduction.............................................................................................................. 4 Electrical Safety....................................................................................................... 4 Hot Surfaces............................................................................................................ 4 Water Borne Hazards .............................................................................................. 5 Description .................................................................................................................. 6 Overview.................................................................................................................. 6 Installation ................................................................................................................. 13 Advisory................................................................................................................. 13 Installation Process ............................................................................................... 13 Electrical Wiring Diagram ...................................................................................... 24 Operation .................................................................................................................. 25 Operating the Software.......................................................................................... 25 Operating the Equipment....................................................................................... 34 Using Customer Generated Software with HT30XC ............................................. 45 Equipment Specifications.......................................................................................... 58 Overall Dimensions ............................................................................................... 58 Heater specifications ............................................................................................. 58 Fluid flow rates ...................................................................................................... 58 Electromagnetic compatibility ................................................................................ 58 Facilities required .................................................................................................. 58 Computer specifications ........................................................................................ 59 Cold water supply .................................................................................................. 59 Cooling water drain................................................................................................ 59 USB Channel Numbers ......................................................................................... 60 Environmental Conditions...................................................................................... 62 ii

Table of Contents Routine Maintenance ................................................................................................ 64 Responsibility ........................................................................................................ 64 General.................................................................................................................. 64 Gaining Access to the Plinth Base ........................................................................ 64 Re-calibration of the thermocouple conditioning circuits ....................................... 65 Draining the hot water system ............................................................................... 65 Freeing a seized hot water pump .......................................................................... 66 Location of potentiometers on the PCB................................................................. 67 Contact Details for Further Information ..................................................................... 68

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Disclaimer This document and all the information contained within it is proprietary to Armfield Limited. This document must not be used for any purpose other than that for which it is supplied and its contents must not be reproduced, modified, adapted, published, translated or disclosed to any third party, in whole or in part, without the prior written permission of Armfield Limited. Should you have any queries or comments, please contact the Armfield Customer Support helpdesk (Monday to Friday: 0800 – 1800 GMT). Contact details are as follows: United Kingdom

International

(0) 1425 478781 (calls charged at local rate)

+44 (0) 1425 478781 (international rates apply)

Email: [email protected] Fax: +44 (0) 1425 470916

Copyright and Trademarks Copyright © 2009 Armfield Limited. All rights reserved. Any technical documentation made available by Armfield Limited is the copyright work of Armfield Limited and wholly owned by Armfield Limited. Brands and product names mentioned in this manual may be trademarks or registered trademarks of their respective companies and are hereby acknowledged.

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General Overview The Armfield range of small scale heat exchangers comprises several units which represent the common types of heat exchanger found in industry and demonstrate different techniques for indirect transfer of heat from one fluid stream to another. Their small size produces a fast system response to changes in variables such as water flow rate and temperature, so that training exercises can be carried out in a relatively short space of time. The types of heat exchanger available include Tubular (HT31), Plate (HT32), Shell & Tube (HT33), Jacketed Vessel with Coil and Stirrer (HT34), Extended Tubular (HT36) and Extended Plate with Regeneration (HT37) which all demonstrate different techniques for indirect transfer of heat from one fluid stream to another. The interchangeable heat exchangers are individually mounted on a service unit (HT30XC) which provides the required services and sensor output displays. The units can be quickly changed without the need for tools, and the service unit also allows students to evaluate experimental heat exchangers of their own construction. Once a heat exchanger has been installed on the service unit and the unit is switched on, the entire assembly can be operated remotely from a WindowsTM computer (NOT supplied by Armfield). The supplied Armfield control software also includes a full set of training exercises and allows data logging and display of results in tabular and graphical format.

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Equipment Diagrams

Figure 1 Simplified Block Schematic Diagram of the HT30XC

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Important Safety Information Introduction All practical work areas and laboratories should be covered by local safety regulations which must be followed at all times. It is the responsibility of the owner to ensure that all users are made aware of relevant local regulations, and that the apparatus is operated in accordance with those regulations. If requested then Armfield can supply a typical set of standard laboratory safety rules, but these are guidelines only and should be modified as required. Supervision of users should be provided whenever appropriate. Your Computer Controlled Heat Exchanger Service Unit has been designed to be safe in use when installed, operated and maintained in accordance with the instructions in this manual. As with any piece of sophisticated equipment, dangers exist if the equipment is misused, mishandled or badly maintained.

Electrical Safety The equipment described in this Instruction Manual operates from a mains voltage electrical supply. It must be connected to a supply of the same frequency and voltage as marked on the equipment or the mains lead. If in doubt, consult a qualified electrician or contact Armfield. The equipment must not be operated with any of the panels removed. To give increased operator protection, the unit incorporates a Residual Current Device (RCD), alternatively called an Earth Leakage Circuit Breaker, as an integral part of this equipment. If through misuse or accident the equipment becomes electrically dangerous, the RCD will switch off the electrical supply and reduce the severity of any electric shock received by an operator to a level which, under normal circumstances, will not cause injury to that person. At least once each month, check that the RCD is operating correctly by pressing the TEST button. The circuit breaker MUST trip when the button is pressed. Failure to trip means that the operator is not protected and the equipment must be checked and repaired by a competent electrician before it is used.

Hot Surfaces This apparatus is capable of producing temperatures that could cause burns / serious burns. 

Allow time for the equipment to cool before handling any of the components.



Do not touch any surfaces with a ‘Hot Surfaces’ warning label.



Do not allow the apparatus to come into contact with flammable materials or liquids.



Do not cover or store the equipment until it has cooled.



Any safety guards are there for operator protection- they must not be removed except as described in this manual, and nothing should be inserted through the guards.

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Important Safety Information 

Always operate the apparatus according to the Operational Procedures described in this manual.



The apparatus should not be left unattended while switched on.

Water Borne Hazards The equipment described in this instruction manual involves the use of water, which under certain conditions can create a health hazard due to infection by harmful micro-organisms. For example, the microscopic bacterium called Legionella pneumophila will feed on any scale, rust, algae or sludge in water and will breed rapidly if the temperature of water is between 20 and 45°C. Any water containing this bacterium which is sprayed or splashed creating air-borne droplets can produce a form of pneumonia called Legionnaires Disease which is potentially fatal. Legionella is not the only harmful micro-organism which can infect water, but it serves as a useful example of the need for cleanliness. Under the COSHH regulations, the following precautions must be observed: 

Any water contained within the product must not be allowed to stagnate, ie. the water must be changed regularly.



Any rust, sludge, scale or algae on which micro-organisms can feed must be removed regularly, i.e. the equipment must be cleaned regularly.



Where practicable the water should be maintained at a temperature below 20°C. If this is not practicable then the water should be disinfected if it is safe and appropriate to do so. Note that other hazards may exist in the handling of biocides used to disinfect the water.



A scheme should be prepared for preventing or controlling the risk incorporating all of the actions listed above.

Further details on preventing infection are contained in the publication “The Control of Legionellosis including Legionnaires Disease” - Health and Safety Series booklet HS (G) 70.

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Description Where necessary, refer to the drawings in the Equipment Diagrams section.

Overview The Service Unit is assembled on a supporting base/plinth, which is vacuum formed in robust ABS plastic and designed for bench mounting.

The plinth incorporates a standard mounting arrangement and service connections for any one of the interchangeable heat exchangers (not supplied with the service unit).

The plinth top incorporates a channel to collect any water which escapes when connecting/disconnecting or dismantling the heat exchangers. A valve at the lefthand end of the channel allows the water to be drained.

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Description

The appropriate heat exchanger is attached to the plinth top by locating the holes in the support plate on the studs in the plinth top and securing it using the knurled thumbscrews provided.

On top of the plinth is the hot water vessel. The water in this vessel is electrically heated. The heating element incorporates an over-temperature C.thermostat that prevents the water being heated beyond a nominal 75 Also in the hot water vessel is a conductivity level sensor that prevents either the heater or pump being turned on unless the vessel is sufficiently full of water.

A lid on top of the vessel prevents excessive loss of water by evaporation.

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The electric supply to the heater is modulated by a solid state relay (SSR) which is located inside the plinth base. The modulation signals to the SSR are provided directly by the computer, via the USB interface. Mounted near the hot water vessel is the gear pump, driven by an electric motor, which is used to circulate the water through the heat exchanger and back to the vessel. The rotational speed of the motor/gear pump, and hence the hot water flow rate, is controlled by the computer software.

The hot water flow rate is measured by the in-line flow meter and displayed on the computer.

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Description

The direction of rotation of the pump can be changed by using the computer software to control a changeover relay mounted in the plinth base. This relay reverses the polarity of the electrical voltage applied to the motor. The cold water flow (the process flow) for the heat exchanger is derived from the local mains water supply. A pressure regulator complete with integral filter/strainer isolates the HT30XC from minor variations in the pressure of this supply. The cold water supply is connected to the inlet of the pressure regulator.

The flow rate through the heat exchanger is then controlled using an electrically driven proportioning solenoid valve. Again this valve is controlled from the computer software.

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A second in-line flow meter measures the cold water flow rate.

Flexible tubes are used to connect the circulator to each heat exchanger and quick release fittings allow rapid connection. Red collars identify the hot water connections and a blue collar identifies the cold water connection. The directional arrows on the red collars indicate the direction of hot water flow when the computer software is configured for counter-current operation.

A panel on the front of the Service Unit contains the MAINS switch with ENABLED indicator, the STOP (Emergency Stop) switch with RUN indicator and input connectors for up to 10 standard ‘k’ type thermocouples, labelled T1 to T10. The thermocouples are supplied with the appropriate heat exchanger accessory. Also mounted on the panel is the connector for the USB interface for connection to the computer, and two USB status indicators. A red ‘power’ LED lights when the unit is 10

Description connected to the PC and a green ‘active’ LED lights when the unit has been recognised by the PC. The USB interface is located behind the front panel. As the unit is software controlled, it is fitted with a ‘watchdog’ circuit which switches off the heaters, pump and cold water control valve in the event of a software ‘crash’ or breakdown in communication between the software and the HT30XC. The watchdog circuit relies on being polled at regular intervals from the computer. If a pulse has not been received for a nominal 10 seconds, a relay circuit is disabled which removes the mains input power from the 24 Vdc power supply and the heaters. The pump drive circuit and valve drive circuit both use the 24 Vdc power, and so when no watchdog pulses are present these circuits cannot be activated. On the rear of the plinth base is a panel containing a number of electrical connectors and devices. The combined MCB/RCD protects the mains electrical circuits inside the plinth. The MCB protects the wiring against excess current in the event of a short circuit or other fault. The RCD (Residual Current Device) protects the operator in the event of an electrical fault or short to earth. All electrical circuits inside the plinth are protected by this device. The operation, purpose and testing of the Residual Current Device is explained in more detail within the Electrical Safety section. Normal operation of the equipment is achieved with the switch in the UP position.

The mains electrical supply is connected to the input socket on the rear panel. A mains lead, fitted with a plug to suit the input connector, is supplied with the Service Unit. The cable allows connection of the unit to an appropriate electrical supply. Output sockets on the rear panel provide a 24Vdc power supply (DC O/P) and a 12Vdc auxiliary supply (AUX O/P). On the right hand side of the plinth base is a removable panel. This panel gives access to the calibration potentiometers for the temperature measurement circuits. This is described in more detail in the Routine Maintenance section of this manual. A label inside the cover shows the location of the individual potentiometers.

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Installation Advisory Before operating the equipment, it must be unpacked, assembled and installed as described in the steps that follow. Safe use of the equipment depends on following the correct installation procedure. Please read the safety considerations included at the front of this Product Manual before attempting to assemble the unit. Installation requirements are listed in the Equipment Specifications section. Priming procedures are described in the Operation section.

Installation Process 1. Remove the apparatus from the box and remove all packaging. Retain the supplied mains lead.

2. Plug the mains electrical lead into the mains inlet socket at the rear of the plinth and connect to a suitable power supply.

3. Ensure that a suitable PC is available:

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4. Insert the CD-ROM into the drive.

5. The CD should autorun. If it doesn't, choose 'run' from the 'start' menu.

6. Type d:\setup.exe where d is the letter of the drive you are using. Click 'OK'.

7. Follow the instructions on the screen. 8. Setup will add a group to the start menu for your Armfield software. To run the software, choose the appropriate shortcut from this group. 14

Installation

9. With the PC switched on, connect the USB port on the HT30XC to a USB port on the computer, using the USB cable supplied. 10. When connected, the red ‘power’ LED on the front of the unit should illuminate. The green ‘active’ LED will also illuminate a short time later.

11. The PC will then display a message saying that it has found new hardware and the new hardware wizard should find the files it requires automatically. 12. Set the pressure regulator to minimum: Pull out the grey knob on the regulator then twist the knob fully anticlockwise.

13. Connect the flexible tubing from the heat exchanger accessory to the base unit as shown:

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HT31

HT32

HT33

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Installation

HT34

HT36

HT37

14. Switch the mains switch to off.

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15. Press the emergency stop button in on the front panel to set it to the stop (in) position.

16. Connect the HT30XC to the electricity mains supply and check that the RCDs on the back panel are switched on with the levers in the up position.

17. Switch the mains switch to on. The ENABLED light should illuminate, indicating that the unit is powered.

18. Release (pull) the Emergency stop button.

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Installation

19. Run the Armfield HT30XC software and choose the counter-current operation option from the start up screen. Go to the ‘diagram’ screen. In the bottom right corner of this screen a message should say ‘IFD: OK’.

If an error message occurs check the USB connection and if necessary reinstall the software. When the computer is connected to the HT30XC, the red and green USB status LED’s on the front panel should both be illuminated. 20. On the computer screen click the ‘Power On’ switch. The green RUN light on the front of the HT10XC should illuminate.

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21. Ensure that the pressure regulator is set to minimum (turned fully anticlockwise).

22. Set the cold water flow control in the software to 100 %.

23. Turn on the cold water supply at the source then gradually increase the flow of cold water by turning the knob on the regulator clockwise.

24. Adjust the pressure regulator until the indicated cold water flowrate is either 5.0 L/min (for HT31, 33 or 36) or 3.0 L/min (for HT32, 34 or 37).

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Installation

25. When the flowrate is correct push in the grey knob to lock the setting.

26. Set the cold water flow control in the software to 0 %.

Note: If there is insufficient water pressure to achieve the recommended maximum flow rate, the full extent of the heat exchanger performance will not be achieved. In this case, set the pressure regulator so the flow at 100% open is approximately 80% of the maximum available flow. The regulator will then still smooth any variations in the mains water pressure. 27. Remove the lid from the hot water vessel. Fill the vessel by pouring clean (preferably demineralised) water until the level is approximately 20 mm from the top.

28. Check that the low-level indication in the software is not activated.

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Armfield Instruction Manual 29. Check that the in-line isolating valves are both fully open.

30. Set the pump speed to 50% in the software. Observe that the hot water pump begins to operate. Run the pump using counter-current operation until all air bubbles are displaced from the flexible tubing into the hot water vessel.

31. Top up the level of this vessel as necessary to maintain the level above the tip of the level electrode (typically 20 mm from the top of the vessel).

32. To access the heater control mode click the software ‘control’ button.

33. In the heater control window, set ‘Mode of Operation’ to ‘Manual’ and ‘Manual Output’ to 50%. Select ‘Apply’.

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Installation

34. Observe that the water heater operates as indicated by a rise in temperature of the circulating hot water. Heated water or bubbles may also be observed rising from the heating element.

35. Set ‘Mode of Operation to ‘Off’ and select ‘OK’ to close the heater control window.

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36. Set the Hot Water Flow rate to 0%.

37. Check the cold water flow control valve: set the Cold Water Flow rate to 50%. Observe that cold water flows through the tubing and heat exchanger. Set the Cold Water Flow rate to 0%.

The HT30XC base unit has now been installed and is fully operational. For further information on the use of the HT30CX refer to the Operation section. If the base unit is to be used with a different heat exchanger, changing heat exchangers is also described in the Operation section.

Electrical Wiring Diagram Click on the relevant link to invoke the Wiring Diagram: Wiring Diagram CDM29213 Printed Versions of this Instruction Manual Please note, all wiring diagrams are appended at the rear of this manual

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Operation Where necessary, refer to the drawings in the Equipment Diagrams section.

Operating the Software Note: The diagrams in this section are included as typical examples and may not relate specifically to the individual product described in this instruction manual. The Armfield Software is a powerful Educational and Data Logging tool with a wide range of features. Some of the major features are highlighted below, to assist users, but full details on the software and how to use it are provided in the presentations and Help text incorporated in the Software. Help on Using the Software or Using the Equipment is available by clicking the appropriate topic in the Help drop-down menu from the upper toolbar when operating the software as shown:

Before operating the software ensure that the equipment has been connected to the IFD5 Interface (where IFD5 is separate from the equipment) and the IFD5 has been connected to a suitable PC using a USB lead. For further information on these actions refer to the Operation manual. Load the software and wait for the presentation screen to open fully as shown:

Before proceeding to operate the software ensure that IFD: OK is displayed at the bottom of the screen. If IFD:ERROR is displayed check the USB connection between the IFD5 and the PC and confirm that the red and green LED’s are both illuminated. If the problem persists then check that the driver is installed correctly (refer to the Operation manual).

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Presentation Screen - Basics and Navigation As stated above, the software starts with the Presentation Screen displayed. The user is met by a simple presentation which gives them an overview of the capabilities of the equipment and software and explains in simple terms how to navigate around the software and summarizes the major facilities complete with direct links to detailed context sensitive ‘help’ texts. To view the presentations click Next or click the required topic in the left hand pane as appropriate. Click More while displaying any of the topics to display a Help index related to that topic. To return to the Presentation screen at any time click the View Presentation icon from the main tool bar or click Presentation from the dropdown menu as shown:

For more detailed information about the presentations refer to the Help available via the upper toolbar when operating the software.

Toolbar A toolbar is displayed at the top of the screen at all times, so users can jump immediately to the facility they require, as shown:

The upper menu expands as a dropdown menu when the cursor is placed over a name. The lower row of icons (standard for all Armfield Software) allows a particular function to be selected. To aid recognition, pop-up text names appear when the cursor is placed over the icon.

Mimic Diagram The Mimic Diagram is the most commonly used screen and gives a pictorial representation of the equipment, with continuously updated display boxes for all the various sensor readings, calculated variables etc. directly in engineering units. To view the Mimic Diagram click the View Diagram icon or click Diagram from the View drop-down menu as shown:

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from the main tool bar

Operation

The mimic diagram displayed will depend on the accessory connected to the HT30XC. Refer to ‘Operating the Software’ in the instruction manual supplied with the accessory for more details about the mimic diagram displayed. In addition to measured variables such as Temperature, Pressure and Flowrate (from a direct reading flowmeter), calculated data such as Motor Torque, Motor Speed and Discharge / Volume flowrate (from pressure drop across an orifice plate) are continuously displayed in data boxes with a white background. These are automatically updated and cannot be changed by the user. Manual data input boxes with a coloured background allow constants such as Orifice Cd and Atmospheric Pressure to be changed by over-typing the default value, if required. The data boxes associated with some pressure sensors include a Zero button alongside. This button is used to compensate for any drift in the zero value, which is an inherent characteristic of pressure sensors. Pressing the Zero button just before starting a set of readings resets the zero measurement and allows accurate pressure measurements to be taken referenced to atmospheric pressure. This action must be carried out before the motor is switched on otherwise the pressure readings will be offset. The mimic diagram associated with some products includes the facility to select different experiments or different accessories, usually on the left hand side of the screen, as shown:

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Armfield Instruction Manual Clicking on the appropriate accessory or exercise will change the associated mimic diagram, table, graphs etc to suit the exercise being performed.

Control Facilities in the Mimic Diagram A Power On button allows the motor to be switched off or on as required. The button always defaults to off at startup. Clicking this button switches the power on (1) and off (0) alternately. A box marked Motor Setting allows the speed of the motor to be varied from 0 to 100% either stepwise, by typing in values, or using the up / down arrows as appropriate. It is usual to operate the equipment with the motor initially set to 100%, then reduce the setting as required to investigate the effect of reduced speed on performance of the equipment. When the software and hardware are functioning correctly together, the green LED marked Watchdog Enabled will alternate On and Off. If the Watchdog stops alternating then this indicates a loss of communication between the hardware and software that must be investigated. Details on the operation of any automatic PID Control loops in the software are included later in this section.

Data Logging Facilities in the Mimic Diagram There are two types of sampling available in the software, namely Automatic or Manual. In Automatic logging, samples are taken regularly at a preset but variable interval. In Manual logging, a single set of samples is taken only when requested by the operator (useful when conditions have to be changed and the equipment allowed to stabilize at a new condition before taking a set of readings). The type of logging will default to manual or automatic logging as appropriate to the type of product being operated. Manual logging is selected when obtaining performance data from a machine where conditions need to stabilize after changing appropriate settings. To record a set of set of data values from each of the measurement sensors click the main toolbar. One set of data will be recorded each time the

icon from the icon is clicked.

Automatic logging is selected when transients need to be recorded so that they can be plotted against time. Click the the

icon from the toolbar to start recording, click

icon from the toolbar to stop recording.

The type of logging can be configured by clicking Configure in the Sample dropdown menu from the upper toolbar as shown:

In addition to the choice of Manual or Automatic sampling, the parameters for Automatic sampling can also be set. Namely, the time interval between samples can 28

Operation be set to the required number of minutes or seconds. Continuous sampling can be selected, with no time limit or sampling for a fixed duration can be set to the required number of hours, minutes or seconds as shown:

Tabular Display To view the Table screen click the View Table icon click Table from the View dropdown menu as shown:

from the main tool bar or

The data is displayed in a tabular format, similar to the screen as shown:

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As the data is sampled, it is stored in spreadsheet format, updated each time the data is sampled. The table also contains columns for the calculated values. New sheets can be added to the spreadsheet for different data runs by clicking the icon from the main toolbar. Sheets can be renamed by double clicking on the sheet name at the bottom left corner of the screen (initially Run 1, Run 2 etc) then entering the required name. For more detailed information about Data Logging and changing the settings within the software refer to the Help available via the upper toolbar when operating the software.

Graphical Display When several samples have been recorded, they can be viewed in graphical format. To view the data in Graphical format click the View graph icon tool bar or click Graph from the View drop-down menu as shown:

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from the main

Operation The results are displayed in a graphical format as shown:

(The actual graph displayed will depend on the product selected and the exercise that is being conducted, the data that has been logged and the parameter(s) that has been selected). Powerful and flexible graph plotting tools are available in the software, allowing the user full choice over what is displayed, including dual y axes, points or lines, displaying data from different runs, etc. Formatting and scaling is done automatically by default, but can be changed manually if required. To change the data displayed on the Graph click Graph Data from the Format dropdown menu as shown:

The available parameters (Series of data) are displayed in the left hand pane as shown:

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Two axes are available for plotting, allowing series with different scaling to be presented on the same x axis. To select a series for plotting, click the appropriate series in the left pane so that it is highlighted then click the appropriate right-facing arrow to move the series into one of the windows in the right hand pane. Multiple series with the same scaling can be plotted simultaneously by moving them all into the same window in the right pane. To remove a series from the graph, click the appropriate series in the right pane so that it is highlighted then click the appropriate left-facing arrow to move the series into the left pane. The X-Axis Content is chosen by default to suit the exercise. The content can be changed if appropriate by opening the drop down menu at the top of the window. The format of the graphs, scaling of the axes etc. can be changed if required by clicking Graph in the Format drop-down menu as shown:

For more detailed information about changing these settings refer to the Help available via the upper toolbar when operating the software.

PID Control Where appropriate, the software associated with some products will include a single or multiple PID control loops whereby a function on the product can be manually or

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Operation automatically controlled using the PC by measuring an appropriate variable and varying a function such as a heater power or pump speed. The PID loop can be accessed by clicking the box labelled PID or Control depending on the particular software:

A PID screen is then displayed as shown:

The Mode of operation always defaults to Manual control and 0% output when the software is loaded to ensure safe operation of the equipment. If appropriate, the operator can retain manual operation and simply vary the value from 0 to 100% in the Manual Output box, then clicking Apply. Alternatively, the PID loop can be changed to Automatic operation by clicking the Automatic button. If any of the PID settings need to be changed from the default values then these should be adjusted individually before clicking the Apply button.

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Armfield Instruction Manual The controller can be restored to manual operation at any time by clicking the Manual button. The value in the Manual Output box can be changed as required before clicking the Apply button. Settings associated with Automatic Operation such as the Setpoint, Proportional Band, Integral Time, Derivative Time and Cycle Time (if appropriate) can be changed by the operator as required before clicking the Apply button. Clicking Calculations displays the calculations associated with the PID loop to aid understanding and optimization of the loop when changing settings as shown:

Clicking Settings returns the screen to the PID settings. Clicking OK closes the PID screen but leaves the loop running in the background. In some instances the Process Variable, Control variable and Control Action can be varied to suit different exercises, however, in most instances these boxes are locked to suit a particular exercise. Where the variables can be changed the options available can be selected via a drop-down menu.

Advanced Features The software incorporates advanced features such as the facility to recalibrate the sensor inputs from within the software without resorting to electrical adjustments of the hardware. For more detailed information about these advanced functions within the software refer to the Help available via the upper toolbar when operating the software.

Operating the Equipment Fitting the required heat exchanger Important: Set pressure regulator to minimum

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Operation Before connecting the equipment to the cold water supply, first close the pressure regulator as follows:

Pull out the grey knob on the regulator then twist the knob fully anticlockwise. Failure to do this may prevent correct operation of the cold water flow control valve. Setting the Cold Water Pressure Regulator must be completed before attempting to set the cold water flow rate. Note: To disconnect the flexible tubing from a quick release connector, push the black ring hard against the body of the connector while pulling the flexible tubing away from the connector. (Do not allow the collet to move away from the body of the connector while pulling the flexible tubing). Refer to the diagrams in Operation of Quick Release Fittings for further information. Attach the required heat exchanger to the HT30XC Computer Controlled Heat Exchanger Service Unit by locating it on the mounting studs and replacing the knurled thumbscrews. The accessories should be plumbed to the service unit. The arrows on the equipment correspond to countercurrent flow within the Heat Exchanger. The computer software is used to alter the direction of flow in order to produce cocurrent flow. Connections should be as follows: Connect the Heat Exchanger cold water inlet to the quick release cold water outlet connector on the HT30XC (The cold water outlet is identified by a Blue collar). Connect the two hot water flexible tubes from the Heat Exchanger (Red collars) to the quick release hot water inlet and outlet connectors on the HT30XC (Red Collars) and open the in-line isolating valves. Note the arrows on the hot water connectors refer to the hot water flow direction with the computer configured for counter-current operation. Diagrams of the connections for each of the HT30XC accessories are included in the Installation section.

Operation of Quick Release Fittings Quick release fittings are used on the equipment for convenience when changing the configuration or removing items for cleaning. The diagrams below show the simple operation of these fittings:

To connect to a quick release fitting Align the parallel section of the rigid tube with the loose collet on the quick release fitting and push firmly until the tube stops.

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An 'O' ring inside the fitting provides a leak-proof seal between the tube and the fitting. The collet grips the tube and prevents it from being pulled out from the fitting.

To disconnect from a quick release fitting Push the loose collet against the body of the quick release fitting while pulling the tube firmly. The tube will slide out from the fitting. The tube/fitting can be assembled and disassembled repeatedly without damage.

Switching on the Unit Switch the mains switch to off

Check that the pressure regulator is closed.

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Operation

Press the emergency stop button in on the front panel to set it to the stop (in) position.

Connect the HT30XC to the electricity mains supply and check that the RCDs on the back panel are switched on with the levers in the up position.

Switch the mains switch to on. The red ENABLED light should illuminate, indicating that the unit is powered.

Release (pull) the Emergency stop button.

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The unit may now be controlled remotely, subject to the unit receiving watchdog pulses from the software. Run the Armfield software for the accessory that has been fitted and choose the counter-current operation option from the start up screen. Go to the ‘diagram’ screen. In the bottom right corner of this screen a message should say ‘IFD: OK’.

If an error message occurs check the USB connection and if necessary re-install the software. When the computer is connected to the HT30XC, the red and green USB status LED’s on the front panel should both be illuminated. On the computer screen click the ‘Power On’ switch. The green RUN light should illuminate on the front of the HT30XC.

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Operation

Setting the cold water pressure regulator Ensure that the pressure regulator is closed (pull grey knob away from regulator, and turn fully anticlockwise).

Set the cold water flow control in the software to 100 %.

Turn on the cold water supply at the source then increase the flow of cold water by turning the knob on the regulator slowly clockwise to a flow rate corresponding to the accessory fitted, as follows: HT31, HT33, HT36: 3 L/min* 39

Armfield Instruction Manual HT32, HT34, HT37: 5.0 L/min*

*Note: Adjusting the pressure regulator to give higher flowrate may cause problems with the operation of the flow control valve. When the flowrate is correct push in the grey knob to lock the setting.

Set the cold water flow control in the software to 0 %.

Note: If there is insufficient water pressure to achieve the recommended maximum flow rate, the full extent of the heat exchanger performance will not be achieved. In this case, set the pressure regulator so the flow at 100% open is approximately 80% of the maximum available flow. The regulator will then still smooth any variations in the mains water pressure.

Priming the hot water circuit Remove the lid from the hot water vessel. Fill the vessel by pouring clean (preferably demineralised) water until the level is approximately 20 mm from the top.

Check that the low-level indication in the software is not activated.

40

Operation

Check that the in-line isolating valves are both fully open.

Click on the Hot Water Flow ‘Flow’ button to display the Hot Water Flow PID Controller

Then set the Manual Output (pump speed) to 50% in the software and run the pump until all air bubbles are displaced from the flexible tubing into the hot water vessel.

41

Armfield Instruction Manual

Top up the level of this vessel as necessary to maintain the level above the tip of the level electrode (typically 20 mm from the top of the vessel).

Note: Counter-current operation should always be selected when priming the hot water side of a heat exchanger for the first time.

Setting the cold water flow rate The Cold Water Flow Valve can be controlled from the computer software. The valve can be driven from 0% (fully closed), to 100% (fully open) in steps of 1%.

The actual flow rate achieved at any particular setting will be dependent on the water supply pressure, the pressure regulator setting, and the losses through the particular heat exchanger in use. This flow rate is measured by a flow meter and displayed in litres/min on the computer screen. In normal use, the valve setting is adjusted until the desired flow rate is achieved. The flow of cold water through the heat exchanger is always in the same direction.

Setting the hot water flow rate and direction Two modes are available for controlling the hot water flow, a manual (or open loop) control mode to provide constant pump speed and an auto (or closed loop) control mode that automatically varies the pump speed to maintain the required flowrate. Both modes are accessed via the software.

42

Operation To access the hot water flow control mode click the software ‘Flow’ button. The actual flow rate is measured by a flow meter and displayed in l/min on the computer screen.

In manual mode, the hot water pump is run at a constant speed that is operator selectable from 0% to 100%. This mode is useful when assessing energy balances or settling times.

In auto mode, the pump speed is modulated in accordance with a PID algorithm to achieve a stable flow of hot water through the heat exchanger on test. Changes to the flow that would be caused by effects such as viscosity reducing due to increasing temperature are eliminated by automatically adjusting the pump speed. Advanced users may change the P, I and D parameters to perform process control investigations.

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Armfield Instruction Manual

The hot water flow direction is set as a default value in the Armfield Software. If a counter-current exercise is chosen, the flow is in the direction indicated by the arrows adjacent to the two hot water connections. If a co-current exercise is chosen the direction of rotation of the pump and therefore the flow of water is reversed. Project exercises do include the facility to change the hot water flow direction within the PID settings screen. Note: When operating with Manual control of hot water flowrate, a change in the temperature of the water will affect the viscosity of the water resulting in a small change in flowrate. It will therefore be necessary to adjust the hot water flow control in the software if it is required to perform tests at the same flowrate but different temperatures.

Setting the hot water temperature Two modes are available for controlling the hot water temperature, a manual (or open loop) control mode to provide constant heater power and an auto (or closed loop) temperature control mode. Both modes are accessed via the software. To access the heater control mode click the software ‘Heater’ button close to the appropriate sensor (usually T1).

In manual mode, the heaters (‘SSR Drive’) are set to be on for a fixed proportion of time, operator selectable from 0% to 100%. This mode is useful when assessing energy balances or settling times.

44

Operation

In auto mode, the power to the heaters is modulated in accordance with a PID algorithm to achieve a stable temperature at one of the sensors (usually the hot water inlet to the heat exchanger). Advanced users may change the P, I and D parameters to perform process control investigations.

Using a different heat exchanger When it is required to use a different heat exchanger, power the system down and close the isolating valves at the hot water inlet and outlet connectors. The original heat exchanger can now be removed with minimum water loss by disconnecting the quick release fittings. Remember to open the isolating valves before trying to operate the system. It will be necessary to re-prime the hot water system using countercurrent operation and to top up the hot water vessel with clean water.

Using Customer Generated Software with HT30XC Installing the Driver Software Insert the CD-ROM into the drive. The program should start automatically, but if ‘autorun’ is disabled on your computer, go to the start menu, choose ‘run’ and type

45

Armfield Instruction Manual ‘d:\setup’ where d is the letter of your CD-ROM drive. Select the ‘Install Driver Software’ option and follow the instructions on screen. Under Windows 98, the setup program will create the following files on your computer: C:\WINDOWS\INF\OTHERS\ARMFIELD LTDTHERMUSB.INF C:\WINDOWS\INF\OTHERS\ARMUSB.INF C:\WINDOWS\SYSTEM32\DRIVERS\THERMUSB.SYS C:\WINDOWS\SYSTEM32\DRIVERS\ARMUSB.SYS C:\WINDOWS\SYSTEM\ARMIFD.DLL Under Windows 2000 these files will be: C:\WINNT\INF\OTHERS\ARMFIELD LTDTHERMUSB.INF C:\WINNT\INF\OTHERS\ARMUSB.INF C:\WINNT\SYSTEM32\DRIVERS\THERMUSB.SYS C:\WINNT\SYSTEM32\DRIVERS\ARMUSB.SYS C:\WINNT\SYSTEM\ARMIFD.DLL The first two files tells the computer how to recognise the IFD5 when it is plugged in to the PC, the next two files are the drivers for the IFD5's USB interface and the last file is a library file, used to pass data between the user program and the IFD5 driver. Also included on the CD-ROM are a tutorial on constructing a LabView or Matlab data logger, a test program for checking that the apparatus and IFD5 are functioning properly, and a link to the Armfield website.

Connecting the Equipment to the PC Connect the USB socket (23) on the front of the Service Unit to the PC using the USB lead supplied. Run the test program from Start – Programs – Armfield Data Logger – Test Program. Check that the displays show appropriate readings. Refer to the product manual for the apparatus you are using for a list of channel numbers and their functions.

USB Interface Driver Function Calls The driver for the integral Armfield data logger is accessed using function calls to the dynamic link library file ARMIFD.DLL. There are four basic calls that can be made to the library file, based on the four types of data I/O described above. These functions must be supplied with a full set of variables of the correct format. All of the variables passed are 32-bit integer types.

Read Analogue This call returns a value from one of the analogue channels. The syntax for the call is: function ReadAnalog(var channel: integer; var value: integer); stdcall; 46

Operation The stdcall directive indicates that the call is handled in a way which is recognisable by most programming languages, including LabView. The channel number should be selected as follows: 

Channels 0-7 for differential channels



Channels 0-15 for single ended channels



Channels 16-31 for multiplexed channels (where appropriate)

The value returned will be an integer ±2047 corresponding to ±5V. A value of 9999 indicates an error.

Write Analogues This call sends values to the two analogue output channels. The syntax is: procedure WriteAnalogs (var AO1: integer; var AO2: integer);stdcall; The values sent should be between ±2047 corresponding to ±5V.

Read Digitals This call returns the values from one of the eight digital channels. The syntax for the call is: procedure ReadDigital (var channel: integer; var value: integer); stdcall; The return value will be 0 if the channel is off or 1 if the channel is on. A value of -1 indicates an error.

Write Digitals This call writes values from the eight digital output channels. The syntax for the call is: procedure WriteDigitals(var DO1: integer; var DO2: integer; var DO3 : integer; var DO4 : integer; var DO5 : integer; var DO6 : integer; var DO7 : integer; var DO8 : integer); stdcall; The analogue channels use values between –2047 and 2047, relating to –5V to 5V on the apparatus. The digital channels use either a 0 or a 1 for ON or OFF. There are also several more advanced calls that can be made to the IFD5 driver, as listed below:

Set Mode When data is transmitted in single-ended mode, such as on the HT30XC, the mode must be set to single-ended using the following call: procedure SetMode (var Mode : integer); stdcall;

47

Armfield Instruction Manual This call sets the mode for the device to either 8 differential channels (Mode = 0) or 16 open-ended channels (Mode = 1).

C/C++ (Cdecl) Procedures In addition to the above stdcall procedures, the IFD5 driver contains a duplicate set of functions which use the cdecl calling convention. These functions are required when using Matlab to access the IFD5, and it may also be preferable to use them if C or C++ is to be used. The functions are summarised as follows: function CReadAnalog(channel: integer): integer; cdecl; function CReadDigital (channel: integer): integer; cdecl; function CWriteAnalogs (AO1: integer; AO2: integer): boolean; cdecl; function CWriteDigitals (DO1 : integer; DO2 : integer; DO3 : integer; DO4 : integer; DO5 : integer; DO6 : integer; DO7 : integer; DO8 : integer): boolean; cdecl; There is also the function for setting the mode (8 differential or 16 open ended channels) for the analogue data transfer: function CSetMode (Mode : integer); cdecl; Using the methods and function calls detailed above it should be possible to construct a data logging or control program in any programming environment which allows calls to dynamic link libraries (.dll files). Examples of such environments include, but are not limited to C, C++, Delphi (Visual Pascal) and Visual Basic. The following pages give procedures for the construction of simple data loggers using Matlab, LabView and Microsoft Excel.

Building a LabView Data Logger This section assumes that the user has a knowledge of the basics of LabView. Load LabView and choose new VI from the initial menu screen. This will give you a blank document in which to work. Alternatively, you could add the data logging facility to an existing VI. Select View Diagram from the window menu. Make sure that the tools palette and functions palette are visible.

Accessing the Analogue Input Channels From the functions palette, select Advanced and then Call Library Function. Place the icon on the diagram, and double click on it with the selector tool to access the setup page. Click on the browse button at the top of the page, and locate the file C:\WINDOWS\SYSTEM\ARMIFD.DLL. Click on the Function Name box and type ‘ReadAnalog’. Check that Calling Conventions is set to ‘default (StdCall)’ and that the function is set to ‘Run in UI Thread’. 48

Operation Click on the Add a Parameter After button. The parameter area will change, allowing various choices. Name the parameter ‘Channel’, set the Type to ‘numeric’, set the Data Type to ‘Signed 32-bit Integer’ and set Pass to ‘Pointer to Value’. These settings apply to all of the parameters used by the library file. Repeat this step so that there are two parameters, naming the second one 'Value'. When this is done, click OK to close the page. The icon on the diagram should now have four cells on it, representing the two parameters before and after being passed to the library file. The column on the left contains the input parameters, while the column on the right contains the outputs. Popup (click with the right-hand mouse button) the top left-hand cell and choose create constant. Type ‘0’ in the box that appears. Repeat this step for the second cell in the left-hand column. This means that the channel number and output will be set to zero before passing to the library file. Popup on the bottom cell in the right-hand column and choose Create Indicator. A blue box will appear with the caption Value. Click on View Panel in the window menu to see the front panel. There should be an indicator box present, titled 'value'. Save the VI using the file menu, then click on the run continuously button. The value in the indicator box will update continuously, showing the value being read by the IFD5 on channel 0. If the program fails to run, then is probably an error in the Call Library Function page. Check all of the values and settings on this page carefully. This procedure can be repeated in order to create indicators for analogue channels as required.

Accessing the Digital Input Channels Place another Call Library Function icon on the diagram screen, and edit its settings as before. Locate the library file, and ensure that the calling conventions and run 0mode are set correctly. Set the Function Name to ‘ReadDigital’ and specify two parameters to be passed, named Channel and Value, of type ‘numeric’, data type ‘Signed 32-bit Integer’ and pass ‘Pointer to Value’. Click OK to exit. On the diagram, create two constants of 0 as before. For the output parameters, we need to convert the value from integer (0 or 1) to Boolean (true or false) data types. One method of doing this is to compare the value to a constant (1). If the values are the same then the result is true, otherwise it is false. On the Front Panel, Select Boolean from the Controls palette, and choose the Round Light indicator. Return to the diagram, and there will be a green box with T F inside it. Move this box so that it is to the right of the Call Library icon. On the Functions palette select Comparison and then Equal?, and place this icon between the other two. Using the wire tool, connect the output from the top right-hand cell on the Call Library Function and connect to one of the inputs to the Equal? icon. Connect the output from the Equal? icon to the input for the T F indicator. Finally popup on the spare input to the Equal? icon and click create constant. Set the constant value to 1. Save the file before running. The ‘LED’ will light on the screen when the digital channel is switched by the equipment. This can be repeated to build indicators for each digital channel as required, modifying the channel input parameter to view different channels.

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Armfield Instruction Manual

Writing the Analogue Outputs Create a Call Library Function block as before, with the Function Name set to ‘WriteAnalogs’. Define two integer parameters called AO1 and AO2. On the Front Panel create two Digital Control boxes from the Numeric button on the Controls palette. Popup on each of the boxes in turn and select Data Range. Set the representation to Word (I16), the minimum value to –2047, the maximum value to +2047, the increment to 1, and the default to 0. In the If Value is Out of Range box, select ‘coerce’. Return to the diagram and connect the outputs from the two controls (labelled I16) to the input parameters on the Call Library Function icon. Save the file before running. Any analogue outputs on the apparatus (pumps, etc.) will now be set to the values in the boxes.

Writing the Digital Outputs Create a Call Library Function block with a Function Name ‘WriteDigitals’. Add eight parameters, named DO1 to DO8. On the Front Panel create eight Check Box controls from the Boolean button on the Controls palette. Label these DO1 to DO8. On the diagram go to the Functions palette and select Boolean, then Boolean to (0,1). Place the icon on the diagram next to the DO1 control. Using the wire tool, connect the DO1 control to the input to the Boolean icon and connect the output from the Boolean icon to the top input to the Library Function Call icon. Repeat this for all eight controls. Save the file before running. Any digital switches on the equipment can now be controlled from the computer, by clicking on the appropriate check box.

Customising the VI The ‘virtual instrument’ created using the above procedure can now be customised to fit exactly with the requirements of the experiment being performed. Any of the indicators on the front panel can be renamed or deleted as applicable. Controls can also be renamed, but if you wish to delete a control, remember that each Call Library Function block must have a full complement of inputs before it can run. This means that the deleted control must be replaced with a constant of value 0.

Building an Excel Data Logger This section assumes that the user has a knowledge of the basics of Excel. Load Excel and a new spreadsheet should appear. This will give you a blank document in which to work. Alternatively, you could add the data logging facility to an existing spreadsheet. Note: Excel is very sensitive to the syntax used in the functions described in this section. Errors in the syntax may cause Excel to close and the system to become unstable. Care should be taken to ensure that the formulae are entered correctly before pressing the Enter key, and it is sensible to save your work at regular intervals to avoid losing too much should Excel close unexpectedly. The IFD5 interface MUST be plugged in to the PC in order for the Excel data logger to work.

Accessing the Analogue Input Channels Select the cell where you wish the value from the first analogue channel to be displayed. Enter the following formula: 50

Operation =CALL("ArmIFD","ReadAnalog","2NN!",0) This will setup a call to the ArmIFD.DLL file, using the ‘ReadAnalogs’ function. The third parameter (2NN!) indicates that the function requires two variables to be passed, and we want Excel to retrieve the first variable in the list. The zero indicates that we wish to collect channel 0 data. For further help on the parameters passed in this function, see Excel help. Copy this formula down for seven further cells, and increment the fourth parameter by one in each successive cell e.g. the second cell down should contain: =CALL("ArmIFD","ReadAnalog","2NN!",1) These eight cells will then update to read the current values from the eight analogue input channels whenever the spreadsheet is calculated.

Accessing the Digital Input Channels Select the cell where you wish the value from the first digital channel to be displayed. Enter the following formula: =CALL("ArmIFD","ReadDigital","2NN!",0) This will setup a call to the .dll file to read the first digital channel. Copy the cell down seven further rows, and increment the fourth parameter for each cell as before.

Writing the Analogue Outputs Select the cells where you wish to enter the values for the analogue output channels. Enter values of 1024 (50%) in both. In the cells to the right, enter the following formulae (in this example the cells B5 and B6 are used as the entry cells): =CALL("ArmIFD","WriteAnalogs","1NN!",$B$5,$B$6) =CALL("ArmIFD","WriteAnalogs","2NN!",$B$5,$B$6) These formulae take the values from the leftogue output channels. In fact, only one of these formulas is required to send the data, but both are included for completeness of display.

Writing the Digital Outputs Select eight cells where you wish to enter the values for the digital output channels. Enter values of either 0 or 1 in each of the cells (0 for off, 1 for on). In the cells to the right of these, enter the following formula (in this example cells B245 to B32 are used as the entry cells): =CALL("ArmIFD","WriteDigitals","1NNNNNNNN!",$B$25,$B$26,$B$27,$B$28,$B $29,$B$30,$B$31,$B$32) Increment the first digit of the third parameter by one for each successive cell. As for the analogue output call, it is not actually necessary to repeat this formula eight times, but doing so does confirm the values that are sent.

Building a Recalculate Macro The above formulae will get data from the IFD5 interface whenever the spreadsheet is updated. If automatic data retrieval is required then we must write a macro (a short visual basic function) which will force the spreadsheet to update. 51

Armfield Instruction Manual Right-click on the toolbars at the top of the screen, and choose the ‘Forms’ toolbar. Place a button on the sheet. The macro window will appear; click OK to add a new macro. The code editor window will appear, with the module for the spreadsheet in the main window. Replace the code for the button click which you have just generated with the following code: Dim Running As Boolean Sub Button1_Click() Dim Start Running = True While Running = True Start = Timer Do While Timer < Start + 0.5 DoEvents Loop Calculate Wend End Sub Insert another button and assign the macro ‘Button2_Click’ to it. Replace the code for the macro with the following: Sub Button2_Click() Running = False End Sub Save the spreadsheet. The buttons ‘Button1’ and Button2’ can be renamed ‘Start’ and ‘Stop’ respectively. Clicking on the start button will force the sheet to recalculate every 0.5 seconds. Clicking on the stop button will halt this process.

Building a Matlab Data Logger This section assumes that the user has a knowledge of the basics of Matlab. To access the IFD5 from Matlab, you will need access to a C or C++ compiler. It may be possible to use the compiler supplied with Matlab, but this tutorial is based on the Microsoft C++ compiler. Ensure that you have set up your C compiler for use with Matlab using the command: > MEX - SETUP You need to create a text file called ARMIFD.DEF in $MATLAB$\extern\include directory, with the following content:

52

Operation LIBRARY ArmIFD.dll EXPORTS SetMode CSetMode ReadAnalog ReadDigital WriteAnalogs WriteDigitals CReadAnalog CReadDigital CWriteAnalogs CWriteDigitals This defines the functions in the Dynamic Link Library (.dll) file which are to be used by Matlab.

Accessing the Analogue Input Channels To access the functions within the .dll we need to create a C program, which can be called from within Matlab. Create a new text file called ANREAD.C in the $MATLAB$\work directory. Enter the following text: #include "mex.h" long CReadAnalog(long channel); void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[] ) { int i; long ans; mexPrintf("\n - Armfield IFD5 - \n\n Analogue Channels \n\n"); i = 1; while (i < 9) { ans = CReadAnalog(i-1); mexPrintf(" AI %i: %d\n",i, ans);

53

Armfield Instruction Manual i = i + 1; } } This code defines a function CReadAnalog which returns a value from the IFD5 channel corresponding to the channel number sent. It then defines a long variable to store the answer, and an int variable to act as a loop counter. Using a ‘while’ loop we check each of the 8 channels in turn, and print the answer onto the screen. Compile and run the program using the command line: > MEX ANREAD.C ARMIFD.DLL > ANREAD The values from the eight IFD5 analogue channels will be displayed. The range of the values is ±2047 corresponding to ±5V.

Accessing the Digital Input Channels Create a new text file called DIGREAD.C and enter the following code: #include "mex.h" long CReadDigital(long temp); void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[] ) { int i; long ans; ldiv_t div_result; int digitals[8]; mexPrintf("\n - Armfield IFD5 - \n\n Digital Channels \n\n"); ans = CReadDigital(0); i = 1; while (i < 9) { if ((ans & 1) == 1) digitals[i] = 1; else digitals[i] = 0; 54

Operation div_result = ldiv(ans, 2); ans = div_result.quot; i = i+1; } mexPrintf(" DI 1: %d\n", digitals[1]); mexPrintf(" DI 2: %d\n", digitals[2]); mexPrintf(" DI 3: %d\n", digitals[3]); mexPrintf(" DI 4: %d\n", digitals[4]); mexPrintf(" DI 5: %d\n", digitals[5]); mexPrintf(" DI 6: %d\n", digitals[6]); mexPrintf(" DI 7: %d\n", digitals[7]); mexPrintf(" DI 8: %d\n", digitals[8]); } This code defines a function that reads the data from the eight digital channels on the IFD5, returned as an eight bit word. It also defines a long variable to receive the result, and an array of eight integers to receive the channel values. The code calls the function, and receives an eight bit word (ans). It then loops through the word, checking whether each bit is a 1 or a 0, and setting the appropriate value in the Digitals array. Compile and run the program as before.

Writing the Analogue Outputs Create a new text file called ANWRITE.C and enter the following code: #include "mex.h" bool CWriteAnalogs(long AO1, long AO2); void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[] ) { int i; long mode, ans, AO1, AO2; bool res; AO1 = 1024; AO2 = 1024; res = CWriteAnalogs(AO1, AO2);

55

Armfield Instruction Manual mexPrintf("\n Analog Outputs Written\n\n"); } This code defines a function called CReadAnalogs that takes two long parameters and passes them to the .dll. It then informs the user that the channels have been written. Compile and run the program as before. Matlab will output values of 1024 to each of the analogue outputs (e.g. a pump on the apparatus would rotate at 50% of its maximum speed).

Writing the Digital Outputs Create a new text file called DIGWRITE.C and enter the following text: #include "mex.h" bool CWriteDigitals(int DO1,int DO2,int DO3,int DO4,int DO5,int DO6,int DO7,int DO8); void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[] ) { int I, digitals[8]; long mode, ans; while (i < 9) { digitals[i] = 1; } mexPrintf("\n Analog Outputs Written\n\n"); res = CWriteDigitals(digitals[1],digitals[2], digitals[3],digitals[4], digitals[5],digitals[6], digitals[7],digitals[8]); mexPrintf(" Digital Outputs Written\n\n"); } This code defines a function that passes eight integer parameters to the IFD5 digital outputs. It sets all f the values in the ‘digitals’ array to 1, sends them to the .dll, and then informs the user that the channels have been written.

Set Mode The other function defined previously for use with C or C++ is the SetMode call, which is used to set either differential or single ended data transfer. If the apparatus 56

Operation you are using has 16 single ended analogue channels rather than eight differential channels, it will be necessary to use this function before the data transfer is commenced.

57

Equipment Specifications Overall Dimensions Height - 430 mm Length - 1000 mm Depth - 500 mm Hot water vessel capacity: 1.5 litres

Heater specifications Heater: 2 x 1 kW elements at 115V. The elements are wired in parallel for 115V systems and series for 230V systems. Heater Thermostat Setting: 75 oC

Fluid flow rates Hot Water Flow Rate: Up to +/- 5 litres/minute, dependent on the Heat Exchanger being used. Heat Exchangers with higher head losses (e.g. HT32) will limit the maximum flow achievable. Cold Water Flow Rate: Up to 5 litres/min dependent on the head of cold water available and the head losses in the heat exchanger.

Electromagnetic compatibility This apparatus is classified as Education and Training Equipment under the Electromagnetic Compatibility (Amendment) Regulations 1994. Use of the apparatus outside the classroom, laboratory or similar such place invalidates conformity with the protection requirements of the Electromagnetic Compatibility Directive (89/336/EEC) and could lead to prosecution.

Facilities required The equipment is designed for installation on a firm, level work surface, such as a laboratory bench, adjacent to a sink unit or cold water supply with appropriate drain. Although the unit is self-contained, it will be necessary to connect cold water and mains electrical supplies.

Electrical supply for version HT30XC-A The equipment requires connection to a single phase, fused electrical supply. The standard electrical supply for this equipment is 220/240V, 50Hz. Check that the voltage and frequency of the electrical supply agree with the label attached to the supply cable on the equipment. Connections should be made as follows: GREEN/YELLOW - EARTH BROWN - LIVE (HOT)

58

Equipment Specifications BLUE - NEUTRAL Fuse rating - 10 AMP

Electrical supply for version HT30XC-B The equipment requires connection to a single phase, fused electrical supply. The standard electrical supply for this equipment is 120V/60Hz. Check that the voltage and frequency of the electrical supply agree with the label attached to the supply cable on the equipment. Connections should be made as follows: GREEN/YELLOW - EARTH BROWN - LIVE (HOT) BLUE - NEUTRAL Fuse rating - 20 AMP

Electrical supply for version HT30XC-G The equipment requires connection to a single phase, fused electrical supply. The standard electrical supply for this equipment is 220V/60Hz. Check that the voltage and frequency of the electrical supply agree with the label attached to the supply cable on the equipment. Connections should be made as follows: GREEN/YELLOW - EARTH BROWN - LIVE (HOT) BLUE - NEUTRAL Fuse rating - 10 AMP

Computer specifications Remote operation of the unit requires a computer running WindowsTM 98, WindowsTM 2000 or WindowsTM XP with an available USB interface. For best results it should have a minimum processor speed of 500 MHz, have 64 Mb or more of RAM and 20 Mbytes of free hard disk space. Armfield do not supply this computer.

Cold water supply The unit requires connection to a source of clean, cold water with a minimum flowrate of 5 litres/min @ 1.25 Bar gauge. To demonstrate the heat exchangers fully, the source of cold water should be below 20°C. The equipment will operate with cold water at a higher temperature but the driving force in the exchanger will be reduced.

Cooling water drain The heat exchanger used in conjunction with the Service Unit will require one of its flexible drain tubes connecting to a suitable drain to dispose of the cold water flow. (As the cooling water used in this unit is only warmed by the heat exchanger and does not become polluted, the water can be recycled provided that the capacity of the system is large enough to minimise temperature rise as the various tests are performed.)

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Armfield Instruction Manual

USB Channel Numbers The interface between the Armfield heat exchanger bench and the computer is a Universal Serial Bus (USB) interface, meeting the standard Microsoft protocols. Armfield are registered with Microsoft as an authorised supplier of USB interfacing equipment. The interface is capable of passing data on 26 channels, as described below: 

Analogue Inputs – 8 differential channels or 16 single ended channels, each with –5V to 5V signals digitised into a 12-bit number. The interface will pass a value between –2047 and 2047 to the computer.



Analogue Outputs – 2 channels, each with –5V to 5V signals, taken from a 12-bit number. Computer must pass a value between –2047 and 2047 to the unit.



Digital Inputs – 8 channels each receiving a 0 or 1.



Digital Outputs – 8 channels each passing a 0 or 1.

The channel allocations for the HT30XC are tabulated below. Channel Code

Use

Scaling

Analog Signals from Heat Exchanger to Computer 0

T1

Hot water temperature

-5V = 0 oC, +5V = 133 oC

1

T2

Hot water temperature

-5V = 0 oC, +5V = 133 oC

2

T3

Hot water temperature

-5V = 0 oC, +5V = 133 oC

3

T4

Hot water temperature

-5V = 0 oC, +5V = 133 oC

4

T5

Hot water temperature

-5V = 0 oC, +5V = 133 oC

5

T6

Cold water temperature

-5V = 0 oC, +5V = 133 oC

6

T7

Cold water temperature

-5V = 0 oC, +5V = 133 oC

7

T8

Cold water temperature

-5V = 0 oC, +5V = 133 oC

8

T9

Cold water temperature

-5V = 0 oC, +5V = 133 oC

60

Equipment Specifications

9

T10

Cold water temperature

-5V = 0 oC, +5V = 133 oC

10

F hot

Hot Water Flow

0V = 0 L/min, 5V= 25 L/min

11

F cold

Cold Water Flow

0V = 0 L/min, 5V= 25 L/min

12

Not used

13

Not used

14

Not used

15

Not used

Analog Signals from Computer to Process 0V = stopped 0

P1

Hot Water Pump Speed 5V = full speed 0V = Closed

1

V1

Cold Water Valve Setting

1.5V = Just Opening 3.5V = Fully open

Digital Signals from Process to Computer 0

Not Used

1

Not Used

2

3

4

Low Level

Monitors the water level in the 0 = Low Level hot water vessel 1 = OK Not Used

Monitors the output of the overThermo-stat/ temperature thermostat AND 0 = Over Temp Level the water level in the hot water 1 = OK Monitor vessel

5

Not used

6

Not used

7

Not used

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Armfield Instruction Manual

Digital Signals from Computer to Process

Power on request

Allows the power on relay to be 0 = Power Off energised, subject to the presence of an appropriate 1 = Power On watchdog pulse

1

Watchdog Pulse

Pulsed signal to keep the watchdog circuit energised, enabling the Heat Exchanger bench power to be turned on

2

SSR Drive

Time modulated signal 0 = heater off controlling the hot water heater 1 = heater on Solid State Relay (SSR)

3

Pump Direction

Controls the change–over relay 0 = countercurrent which reverses the hot water 1 = cocurrent pump direction

4

Stirrer On

Only used on HT34

0

Pulsed signal, min rate 1 pulse every 5 seconds

0 = off 1 = on 0 = off

Aux. Heater Control

5

1 = on

6

Not used

7

Not used

Environmental Conditions This equipment has been designed for operation in the following environmental conditions. Operation outside of these conditions may result reduced performance, damage to the equipment or hazard to the operator. a. Indoor use; b. Altitude up to 2000 m; c. Temperature 5 °C to 40 °C; d. Maximum relative humidity 80 % for temperatures up to 31 °C, decreasing linearly to 50 % relative humidity at 40 °C; e. Mains supply voltage fluctuations up to ±10 % of the nominal voltage; f.

Transient over-voltages typically present on the MAINS supply; Note: The normal level of transient over-voltages is impulse withstand (overvoltage) category II of IEC 60364-4-443;

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Equipment Specifications g. Pollution degree 2. Normally only nonconductive pollution occurs. Temporary conductivity caused by condensation is to be expected. Typical of an office or laboratory environment

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Routine Maintenance Responsibility To preserve the life and efficient operation of the equipment it is important that the equipment is properly maintained. Regular maintenance of the equipment is the responsibility of the end user and must be performed by qualified personnel who understand the operation of the equipment.

General 1. The equipment should be disconnected from the electrical supply when not in use. 2. The heat exchanger under evaluation, the hot water vessel and the channel in the support plinth base should be drained after use. 3. The various plugs and sockets on the equipment should be given a light spray of de-moisturising lubricant at regular intervals to ensure smooth and reliable connections. 4. Test the RCD by pressing the TEST button at least once a month. If the RCD does not trip when the TEST button is pressed then the equipment must not be used and should be checked by a competent electrician. 5. The level electrode inside the hot water vessel should be cleaned at regular intervals to ensure electrical contact with the water.

Gaining Access to the Plinth Base Maintenance of the HT30XC Computer Controlled Heat Exchanger Service Unit does not require access to the electrical circuits or components located inside the moulded plinth. However, in the event of an electrical problem, it may be necessary for a competent electrician to gain access to the inside of the moulding as follows: Ensure that the Service Unit is disconnected from the electrical supply (not just switched off). Disconnect the cold water supply and remove any heat exchanger accessory installed on Service Unit. Drain the hot water vessel and channel by opening the drain valves. Unscrew the channel drain valve located in the recess at the left-hand end of the moulded plinth. Unscrew the six fixings around the periphery of the plinth top. Carefully lift the top moulded section away from the bottom moulded section and place the top section in a suitable location. Whilst partially raised, disconnect the electrical connections between the top and bottom plinth sections by disconnecting the appropriate connector. The electrical circuits inside the bottom moulded plinth section are accessible for working on. Refer to the Installation section for the Electrical Wiring Diagram.

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Routine Maintenance

Re-calibration of the thermocouple conditioning circuits The thermocouple conditioning circuits (which provide readings from the thermocouples fitted to each of the heat exchangers) are located on a PCB inside the electrical console. These circuits are calibrated before despatch and should not require recalibration. However, if adjustment becomes necessary, each circuit has a Zero (offset) and a Span (gain) potentiometer which are accessible behind the cover on right hand side of the plinth base. A diagram is included inside the cover to identify the positions of the potentiometers but refer to the diagram in Location of potentiometers if necessary. As the HT30XC base unit has no integral sensor display, the outputs from the temperature sensors must be monitored using a connected computer running HT30X range software that includes all temperature output signals. The Project Work exercises for HT36 or HT37 would be most suitable for this purpose. Note that the PC will indicate 66.5oC for T1-T10 if HT30XC is switched off or the USB is not active (lead is disconnected). The PC will indicate 133oC (full scale) for T1-T10 if thermocouples are disconnected from HT30XC. Calibration is best performed using a thermocouple calibrator and mV meter as follows: Measure the Cold Junction Temperature using a mV meter connected to pins 1 & 2 on the connector marked CJ REF. The voltage output is 10mV/ °C. Connect a thermocouple simulator (set to type K / auto cold junction) to thermocouple socket T1 on the front of HT30XC. Set the thermocouple simulator output to the measured CJ REF temperature and check the corresponding reading on the PC. Adjust the T1 Zero potentiometer if necessary to give the correct reading. Set the thermocouple simulator to the measured CJ REF temperature + 60oC and check the corresponding reading on the PC. Adjust the T1 Span potentiometer if necessary to give the correct reading. Recheck the Zero and Span settings and adjust the appropriate potentiometer if necessary. Repeat this procedure for channels T2 to T10 with the calibrator connected to the appropriate thermocouple socket on the front of HT30XC. If a thermocouple simulator is not available then a Type K thermocouple or a thermocouple from one of the optional heat exchangers can be used with crushed ice and boiling water as the reference points. The Zero and Span adjustments should then be carried out to give readings of 0oC and 100oC as appropriate.

Draining the hot water system The hot water vessel can be easily drained down to a low level, by opening the drain valve on the side. This is adequate for normal use and short-term storage. For transport or long term storage, the two isolating valves should be left open and the vessel and flexible tubing should be totally drained.

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Armfield Instruction Manual

Freeing a seized hot water pump In normal use the hot water pump should not require any routine maintenance and running should keep the gears free from scale due to hard water etc. However, if the water is contaminated with flakes of hardness or dirt particles then the gears inside the pump might seize because of the small operating clearances that are necessary. If the hot water pump does not operate when switched on it then it will be necessary to check the pump as follows: Disconnect the electrical supply to the equipment. Drain the water from the hot water vessel by opening the drain valve at the base of the vessel. It is not necessary to remove any heat exchanger installed on the HT30XC but the isolating valves on the manifold block should be closed to minimize loss of water when the pump is opened. Remove the rectangular end cover from the head of the pump by unscrewing the four cap headed screws using a hexagon wrench (Allen key). Any water draining from the pump will drain into the top of the plinth. Inspect the gears, cover etc for any contamination and clean as necessary but do not use any harsh abrasives or volatile solvents on the plastic gears or aluminium body. If it is necessary to remove the plastic gears take care not to damage the gears or to lose the drive key inside the driven gear. If the gears are stubborn to remove then a pair of tweezers or similar tool may be used to extract the gears by grasping one of the flutes on the gear. When the pump is clean replace the gears ensuring that the drive key is correctly located in the slot in the driven shaft. Ensure that the sealing gasket is correctly located in the groove on the end face of the pump body then replace the cover plate and secure it using the four screws. Reconnect the electrical supply, refill the hot water vessel then check satisfactory operation of the pump. Note that when priming the system countercurrent operation should be selected in the computer software to ensure proper priming of the pump and pipework and heat exchanger. Topping up of the hot water vessel will be necessary until the system is full of water.

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Routine Maintenance

Location of potentiometers on the PCB

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Contact Details for Further Information Main Office:

Armfield Limited Bridge House West Street Ringwood Hampshire England BH24 1DY Tel: +44 (0)1425 478781 Fax: +44 (0)1425 470916 Email: [email protected] Web: http://www.armfield.co.uk

US Office:

Armfield Inc. 436 West Commodore Blvd (#2) Jackson, NJ 08527 Tel: (732) 928 3332 Fax: (732) 928 3542 Email: [email protected]

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