Which products are affected?
ESP-DDS2-x (Global Drive PLC Developer Studio V2.0 - V2.2)
What happens?
The value of some codes can only be modified when the PLC target system (e. g. Servo PLC) is stopped or inhibited. Code C0081 (rated motor power) can, e. g., only be written when the PLC target system is inhibited.
If the value of the code is modified, although the modification condition (inhibited or stopped controller) is not considered, DDS logs off with the following communication error:
Communication Error (#41729): Logout Performed
When you have confirmed the communication error you can log in the PLC target system with DDS again.
When does the problem occur?
The above-described behaviour occurs when the Systembus Server Driver has been selected as communication driver and the value of a code is modified, although the condition for modification of this code has not been fulfilled.
Possible diagnostics?
No.
Short-term measures/recommendations?
Before you modify a code make sure that all required conditions are fulfilled.
This function restriction will be eliminated with the next DDS update.
Evaluation:
Modification of a code leads to a communication error when the condition for modification of a code (e. g. controller inhibit) is not fulfilled. Due to this communication errors the connection between PLC target system and DDS is interrupted. This is the interference on the participants of the system bus. Directly after the communication error you can log in the target system with DDS again.
