Exception reporting

Exception reporting ensures that a PI interface only sends meaningful data, rather than sending unnecessary data that taxes the system.

Exception reporting uses a simple deadband algorithm to determine whether to send events to Data Archive. For each point, you can set exception reporting specifications that create the deadband. The interface ignores values that fall inside the deadband.

In the preceding illustration, the interface reports values A, D, and C to Data Archive. Value A is the last reported value. Values B and C fall within the exception deadband, but value D falls outside the deadband. The interface reports value D along with the previous value: in this case, value C. Compression testing will determine if C needs to be preserved, or if A and D are sufficient to recreate the original signal with the required fidelity.

The interface uses the point's ExcDev, ExcMin, and ExcMax attributes to determine whether to report the new value to Data Archive. For details on setting exception-reporting attributes, see ExcDev, ExcDevPercent, ExcMax, and ExcMin.

Note: Some interfaces do not support exception reporting. See your interface documentation to determine whether the interface supports this capability.