Redundancy PAS CC Manual

Double/Redundant Configuration 7.1 Connection to Two SICAM PAS Full Servers

7.1

Connection to Two SICAM PAS Full Servers

A SICAM PAS system can consist of two SICAM PAS Full Servers running in parallel. Bay devices and substations are connected to both SICAM PAS Full Servers; via the SICAM PAS channel DLL, SICAM PAS CC is connected to both SICAM PAS Full Servers. The connection to a SICAM PAS Full Server (e. g. to Server1) is referred to as the normal path; the connection to the other SICAM PAS Full Server (e. g. to Server2) is the so-called redundant path. During fault-free operation, the connection via the normal path is active. For SICAM PAS CC, a switchover to the redundant path must be performed if one of the following two scenarios occurs: ‰ The normal path of the SICAM PAS channel DLL to the connected SICAM PAS Full Server

is interrupted. The active connection of the SICAM PAS channel DLL to the SICAM PAS Full Server is permanently monitored. When an error occurs, the system automatically switches over to the redundant path (to the other SICAM PAS Full Server), provided that this path has been configured. ‰ The communication between the SICAM PAS Full Server accessed by SICAM PAS CC and

the bay devices is disturbed. This scenario also requires a switchover to the redundant path. This fault, however, cannot be detected by the SICAM PAS channel DLL. The detection of the fault and the switchover to the redundant path must be realized by other means. The required procedure is described below.

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SICAM, SICAM PAS CC, Human Machine Interface E50417-H8976-C284-A5, Edition 05.2007

Double/Redundant Configuration 7.1 Connection to Two SICAM PAS Full Servers

ConnectionState ForceConnectionState Process tag

SICAM PAS Channel DLL

Channel Control

Ethernet

Server1

Server2 PROFIBUS FMS

Bay Devices Kanal_dll.tif

Figure 7-1 System with double SICAM PAS Full Servers

The following components are required for the monitoring and switchover of the connections (between the normal and the redundant path): ‰ a process tag ‰ the bit array (32 bits) ConnectionState_xxx ‰ the bit array (32 bits) ForceConnectionState_xxx ‰ the WinCC script SicamPAS_ConnectionChange.pas

Process tag In order to be able to monitor the connection between the SICAM PAS Full Server and the bay devices, a process tag (e. g. a message derived via CFC which allows for an evaluation of the quality of the connection to the bay devices) must be created in PAS UI Configuration and mapped to SICAM PAS CC. This process tag can be evaluated using the WinCC script SicamPAS_ConnectionChange.pas. The quality of the active connection can be assessed by means of the evaluation of the process tags.

SICAM, SICAM PAS CC, Human Machine Interface E50417-H8976-C284-A5, Edition 05.2007

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Double/Redundant Configuration 7.1 Connection to Two SICAM PAS Full Servers

ConnectionState The bit array ConnectionState_xxx shows the status of the active connection between the SICAM PAS channel DLL and the SICAM PAS Full Server. The bit array is defined as follows: Bit

Meaning

0

0 = no connection 1 = connection active

1

1 = connection via normal path

2

1 = connection via redundant path

3 to 31

system-internal use

ForceConnectionState The behavior of the SICAM PAS channel DLL can be influenced by writing the system tag ForceConnectionState_xxx. The bit array can only be written completely. Read access is not possible. The bit array is defined as follows:

218

Bit

Meaning

0

If this bit is set, the SICAM PAS channel DLL switches over to the other SICAM PAS Full Server. The triggering is performed using the WinCC script.

1

If this bit is set, the connection is activated via the normal path.

2

If this bit is set, the connection is activated via the redundant path.

3 to 31

Reserved

SICAM, SICAM PAS CC, Human Machine Interface E50417-H8976-C284-A5, Edition 05.2007

Double/Redundant Configuration 7.1 Connection to Two SICAM PAS Full Servers

WinCC script The process tag is evaluated using the WinCC script SicamPAS_ConnectionChange.pas. The proper functioning of the SICAM PAS Full Server (including communication with connected devices) can be checked by means of this evaluation. If the quality of the active connection is found to be bad, the system can switch over to the other path using the system tag ForceConnectionState_xxx. A template of the WinCC script SicamPAS_ConnectionChange.pas is copied into the directory ...\SIEMENS\SICAM\PAS CC\PAS during installation. In order to be able to use the WinCC script, proceed as follows:

• Copy the WinCC script into the PAS directory of your WinCC project. • To customize the WinCC script, apply the related process tags in the script editor. Activating redundancy Proceed as follows to activate the redundant configuration:

• In the WinCC Explorer, right-click on PAS Data Server. Next, select Properties from the context menu. The Channel Unit Properties dialog opens.

• Click the Properties button. The Connection Properties dialog opens. • Click the Properties button. The PAS Connection dialog opens.

pascc404.tif

Figure 7-2 Activating redundancy

• Select the option Redundant Connection. • Enter the IP address of the second SICAM PAS Full Server. • Confirm your settings with OK.

SICAM, SICAM PAS CC, Human Machine Interface E50417-H8976-C284-A5, Edition 05.2007

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