MSTR communication Error check

[MRobert]

We use MSTR blocks for reading registers from one PLC to another. We use MODSOFT.
How do I have to check if a communication error occurs?
-Is it enough to use the middle output of the MSTR block?
-Maybe better to read a register of a counter from the remote PLC and checking if the value changes?
-Maybe better to read the Error register of the MSTR block?

 

[Jim Dungar]

The level of error checking you use is dependent on the importance of the communication.

Most of the time I simply use the error output pin. If this indicates an error then I might look at the error register, but I rarely do this. For citical communications I use either a "heartbeat" pulse or a pair of watchdog timers.

 

[MRobert]

Thank you for answering.

Please explain "heartbeat"

 

[shanvis]

Yes it's a good idea to use "Heartbeat" pulse when communicating between two PLC's for checking the healthiness of the communciation.
"Heartbeat" pulse what I have used is nothing but writing and reading a bit at a continuos interval between the PLCs. The moment we are not able to read or write this bit, it implies that there is an error.

Shan

 

[MRobert]

Thank you Jim and Shan

Thank you Jim and Shan