Applies To:
  • CitectSCADA

All SNMP variable tags for one of my devices display #Com even though I know everything is configured correctly. I have checked the SNMP Service in Windows, the Boards, Ports and I/O Devices configuration in Citect as per the documentation and the OID's etc in the SNMPVars dbf. The MIB2Cit or my 3rd party SNMP client can read the data why can't Citect?

Similar to the MODNET/MODBUS protocol, SNMP establishes communications to a device by checking an initialisation address. In the case of SNMP this is a 'standard' object/OID called 'sysDescr'. Some SNMP agents may not have this object. In this case CitectSCADA can be configured to read an alternative OID by setting the following Citect.ini parameter:

x.y.TestOIDStr = #.#.#.#.#.0
(where x is portname, y is the unitname, and # is the OID ending in 0)

Note: The OID must have a '0' at the end. For more information please read the SNMP help.