Alarm Parameters for PID Block

The standard alarm assignment parameter for deadbank/hysteresis in a DeltaV PID block shows up in Control Studio as Alarm_HYS. As I understand it, this is the hysteresis or deadband value associated with all alarms for that PID block. However, if Conditional Alarming is  enabled, individual hysteresis parameters appear for all configured alarms (i.e. HI_HYS, HI_HI_HYS, LO_HYS, LO_LO_HYS) in addition to the block parameter Alarm_Hys. My question is, if conditional alarming is enabled and the individual hysteresis parameters are configured, what does the general parameter Alarm_Hys do in this case? Is that parameter ignored by the module if conditional alarming is enabled?

  • Yes the ALARM_HYS parameter isn't used when conditional alarming is enabled on the associated blocks.