Scadpack Workbench- V6.5- Heartbeat Counter Communications Setup

Hi Everyone,

I am newbie in programming RTUs. I am currently working on a water infrastructure project. This project involves reading Modbus registers from PLC and mapping that to RTU DNP3 points of Scadapack 535E RTU. The DNP3 Points from RTU has to be read by Remote SCADA(ClearSCADA). We are using Scadapack Workbench V6.5 to program the RTU.

To ensure the communications is not lost between PLC and RTU, a watchdog counter is used in both RTU(Scadapack workbench) and PLC(Unity Pro). These counters are set to be incremented every second . If any of the counter stops incrementing for about 40 seconds time interval, it is assumed that the communication is lost. Is there any sample program to demonstrate this idea.



Regards,

Akash

Create a variable called Last_Count. Every scan compare the last count to the current count. While they remain equal (i.e. comms has failed), run a timer. Set a reasonable timer preset for the "comms fail".

If the count changes (i.e. comms is successful) move the count value to the Last_Count. As the values are no longer equal the timer resets to zero.