OPCIS Health Check

An OPC health check is performed periodically to determine the state of the OPC server and each group. By default, the health check rate is 60 times the group update rate.

For example, if the update rate of the default group (OPCDEFAULTGROUP) is 1000 ms, the health check rate would be 60000 ms. The health check rate can be customized in the service configuration file using the optional OPC_HEALTHCHECK_RATE keyword. The parameter of this keyword defines the health check rate (in milliseconds). If the OPC Facility Group has a status tag to monitor OPC server state (UDC = SYOPCHSTAT), the results of the health check will be written to this tag.

Possible values are:

Value	Description
0	Unknown
1	Normal
2	Failed
3	No Config
4	Suspended
5	Test
6	Comm Fault

A health check can also be forced. This requires that the OPC Facility Group has a status tag to control the group (UDC = SYOPCGCTL). Issuing a setpoint command to this tag with a value of 2 forces the health check. Other options for this tag are described in OPCIS System UDCs.