Download Redundancy PAS CC Manual PDF

TitleRedundancy PAS CC Manual
TagsSoftware Computer Engineering Bit User Interface Server (Computing)
File Size281.7 KB
Total Pages4
Document Text Contents
Page 1

Double/Redundant Configuration

7.1 Connection to Two SICAM PAS Full Servers

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

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.

Page 2

Double/Redundant Configuration

7.1 Connection to Two SICAM PAS Full Servers

217SICAM, SICAM PAS CC, Human Machine Interface
E50417-H8976-C284-A5, Edition 05.2007

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.

Channel
Control

ConnectionState
ForceConnectionState

Process tag

Ethernet

SICAM PAS
Channel DLL

PROFIBUS FMS

Bay Devices

Server1 Server2

Page 3

Double/Redundant Configuration

7.1 Connection to Two SICAM PAS Full Servers

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

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:

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:

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

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

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