WELCOME The topic for today is:
Sensors
Circuit Design for ISO13849-1-2006
Safety Vision Motion Automation Controls
Your presenter is: Heinz Knackstedt
[email protected] (937) 434-8830 Office (937) 545-6494 Cell
A Single Source…A Total Solution
page 1 Design with ISO 13849 110401
Who we are and what we do Thirty+ years serving the automation industry 30 account representatives who live near their customers 12 Technical Support Specialists, both in the field & in the office 8 Customer Service Reps, quotes, delivery information, expediting
Sensors
Large inventory; same day shipping on stock items
Safety
95% or better on time delivery
Vision Motion Automation Controls
Order online, via EDI, Credit Card, Fax, or Phone 24 Hour emergency assistance Lunch & Learns, Seminars, and in-depth training classes Generic Technology or Product application specific www.cesales.com
A Single Source…A Total Solution
800-228-2790 page 2 Design with ISO 13849 110401
Circuits for ISO 13849-1-2006 • Objective – Functional over view of ISO 13849-1 – Establish basis for further self study
• Contents – – – – – – – – –
Background and safety with EN-954-1-1996 Basic Safety Circuit Structure from EN-954-1 Introduction to ISO13849-1 Component failure and MTTFd Evaluation of sub-systems and systems Explanation of DCavg and CCF Example of simplified PL evaluation Commercial PL Calculation programs Simplified example
page 3 Design with ISO 13849 110401
MACHINE SAFETY IS NOT AN OPTION! The General Duty Clause 5(a) (1) of the OSH Act-1970 Public Law 91-596 requires that: Each employer shall furnish to each of his employees, employment and a place of employment, which is free from recognized hazards that are causing or are likely to cause death or serious physical harm
A less well known part 5(b) further states that: Each employee shall comply with occupation safety and health standards and all rules, regulations and orders issued pursuant to this Act which are applicable to his own actions and conduct page 4 Design with ISO 13849 110401
Performance of the Safety Related Parts of the Control System • U.S. – OSHA Control Reliable – No single fault shall cause the loss of the safety function – B11.0-2010 and RIA-15.06-1999 provided some guidance of the construction and performance of the SRP/CS as a function of the level of risk reduction required
• International - Machinery Directive – ISO and EN consensus standards are “harmonized” so that if a machine is designed to these standards, there is a “Presumption of Conformity” with the Machinery Directive. – Standards describe a method of determining the performance and design requirements of a level of risk reduction as established by a Risk Assessment • EN-954-1-1996 • ISO-13849-1-2006 • Hundreds of Machine specific “C” level standards page 5 Design with ISO 13849 110401
Some Background “Safety of Machinery” EN-954-1-1996 Was the Starting point
page 6 Design with ISO 13849 110401
EN-954-1-1996 • • • •
Defined five Level of Risk categories each of which described a safety control system with appropriate performance for its risk reduction It is considered “Deterministic” or “Qualitative” so that conformance to the requirement cannot not be positively established nor “substantiated” Resulted in a “spectrum” of acceptable system performance within a category Specifically defined the categories as “Non Hierarchical” – A system which meets the risk reduction requirements for one risk level, does not necessarily provide a greater risk reduction than one which meets the requirement for a lower risk level. – In practice, the hierarchical approach has been quite successful when • • • •
•
Components of similar reliability are used Exclusions used in a lower category are valid Same preventive maintenance is applied Environmental conditions have the same effect on the devices
This system was adopted as a functional guide line in the US, as initially, there was no similar U.S. system – “Control Reliable” term was used but not well defined. – RIA-15.06-1999 offered an alternative with both a risk assessment and risk reduction strategy, with some specific guidelines, modeled after EN-954-1. – B11.0-2010 has a very qualitative description of the process. page 7 Design with ISO 13849 110401
Example of the “spectrum” within a given category
P.E. Switched Output PLC
PLC Q1
Safety Light Curtain Type 2
SIM Cat 4
5
Using standard Photo Electric sensors, this circuit has been certified by TUV as meeting Cat 2 if monitored by a DEDICATED, but non Safety Rated, PLC The TYPE 2 Safety Light Curtain has been certified as meeting Cat 2 The “probability” of the TYPE 2 safety light screen failing UNSAFELY is incredibly small due to internal testing (per IEC 61496 Type 2) while the chances of a P.E. sensor failing to ON is much higher. The external testing of the P.E. by the standard PLC is less positive Both been certified as meeting the same Category risk reduction requirements. page 8 Design with ISO 13849 110401
EN-954-1 The Process •
Perform a Task based Risk Assessment – Identify all Hazards and the Tasks performed while exposed to them
•
For each Task/Hazard pair, qualify the three variables which together determine the level of risk – Seriousness of the potential injury • Serious • Slight
– Frequency of Exposure to the Hazard • Continuous • Seldom
– Ability to Avoid the Harm • Difficult, hardly possible • Easy, almost assured
•
The Level of Risk identifies a reasonable minimum safety system’s functional performance appropriate to reduce that risk to a tolerable level – There are Five Risk Level Categories B, 1, 2, 3, and 4 – Each has a functional description of the behavior of the safety system under fault conditions, and a suggested circuit architecture to attain such performance. page 9 Design with ISO 13849 110401
P1
EN-954-1-1996
S1
F1
F2 F1
S2
F2
P2 P1 P2 P1 P2 P1 P2
PLr 1/h=λ
SIL
a
