Using fieldbus technology in the control strategy > DeltaV fieldbus function blocks in the control strategy

Limiting perodic writes to static or non-volatile parameters

It is recommended that you limit the number of periodic writes to all static or non-volatile parameters such as HI_HI_LIM, LOW_CUT, SP, TRACK_IN_D, OUT, IO_OPTS, BIAS, STATUS_OPTS, SP_HI_LIM, and so on. Static parameter writes increment the static revision counter, ST_REV, and are written to the device's non-volatile memory. Consult the device documentation to determine if a parameter is static or non-volatile. If writes to a static parameter are unavoidable, it is recommended that the module logic first read the parameter value, then compare the existing value to the new value, and write the new value only if it is outside an acceptable deadband.

Note

fieldbus devices have a non-volatile memory write limit. If a static or non-volatile parameter is configured to be written periodically, the device can stop its normal operation or fail to accept new values after it reaches its limit.