06-PLC Master & 250 PLC Slaves

[Charles]

 
The problem; I've set up the Slave-Master for lost telemetry signal acording to the example provided under the general communications examples on Automations Web site.  This logic works well for making changes or shuting down the operation at the slave. My problem is that when this occurs the Master needs to post an alarm.

[MikeMc]

I pass the scan count between PLC's to make sure that they are communicating by comparing the previous value against the current value. If they are the same the timer starts timing for the communications alarm.