Applies To:
  • CitectSCADA 5.xx, 6.xx

I have a Dialup modbus device that my Citect system connects to. The IOdevice is scheduled to connect every 15 minutes to aquire Data from the PLC, via a Dialup connection. Citect seems to be making the connection however does not disconnect after acquiring Data from the PLC. The connection only gets terminated after the '[Dial]MaxConnectionTime' period is reached. What could be wrong?

This behaviour can be caused by the following parameter

[IOServer]WatchDogPrimary = 1

The above parameter determines whether CitectSCADA periodically checks the communication connection to your primary I/O devices. If you set this parameter to 1, CitectSCADA will check the Primary devices every watch time (as specified by the WatchTime parameter of the device driver). If you set this parameter to 0, you will not be notified of a communication failure until a read to the device is attempted. 

Dialup, Modbus