What happens?
The CoDeSys OPC server does not recognise that the value of a variable has changed and therefore does not update the value of this variable.
When does this behaviour occur?
The behaviour occurs if
- a variable quickly changes its value
and
- an older CoDeSys OPC server (<V3.13) already installed was used to install CoDeSys OPC server V3.13
and
- the "ReadCyclesAfterWrite" entry is not contained in the OPCServer.ini (configuration file of the CoDeSys OPC server) or set to 0.
Which products are affected?
CoDeSys OPC server from V3.13.0.8
Short-term measures:
Start the "OPC Configurator" configuration program for the CoDeSys OPC server. Highlight the "Server" entry in the left configuration tree and
activate the "Writes produce data change calls" entry in the right settings window.
As an alternative, you can also add the "ReadCyclesAfterWrite=2" entry manually in the [Server] section to the OPCServer.ini configuration file in the installation path of the CoDeSys OPC server.
Evaluation/recommendations:
If e.g. an external visualisation is used to display the value of a variable from the PLC program of a Lenze controller via the CoDeSys OPC server, the external visualisation may still display the old variable value if the variable value has changed quickly.
In the case of a quick variable value change, the Lenze controller is connected via the CoDeSys OPC server to a visualisation and a variable is set by the visualisation and immediately reset by the PLC program in the Lenze controller.
