Function Block Properties dialog box - Alarms tab (PIDE)

The Enhanced Proportional Integral Derivative (PIDE) instruction provides enhanced capabilities over the standard PID instruction for control controls of process variables such as flow, pressure, temperature, or level. The PIDE instruction uses the velocity form of the PID algorithm.
Use the
Alarms
 tab to set the values that define alarm conditions for the selected PIDE function block.
The following table describes the parameters available on the
Alarms
 tab:
Parameter
Description
PV
Scaled process variable input. This value is typically read from an analog input module.
  • HHLimit
Sets the high-high alarm limit of the
PVHHLimit
 parameter.
  • HLimit
Sets the high alarm limit of the
PVHLimit
 parameter.
  • LLimit
Sets the low alarm limit of the
PVLLimit
 parameter.
  • LLLimit
Sets the low-low alarm limit of the
PVLLLimit
 parameter.
  • Deadband
Sets the alarm deadband for the
PVDeadband
 parameter.
Deviation
Deviation is the difference in value between the process variable (PV) and the setpoint (SP). Deviation alarming alerts the operator to a discrepancy between the process variable and the setpoint value.
  • HHLimit
Deviation high-high alarm limit value of the
DevHHLimit
 parameter.
  • HLimit
Deviation high alarm limit value of the
DevHLimit
 parameter.
  • LLimit
Deviation low alarm limit value of the
DevLLimit
 parameter.
  • LLLimit
Deviation low-low alarm limit value of the
DevLLLimit
 parameter.
  • Deadband
Deviation alarm deadband value for the
DevDeadband
 parameter.
PV Rate of Change
Compares the change of the input over the
ROCPeriod
 to the rate-of-change limits.
  • Positive
Sets the value of the
PVROCPosLimit
 parameter.
  • Negative
Sets the value of the
PVROCNegLimit
 parameter.
  • Period
Sets the value of the
PVROCPeriod
 parameter.
Status
Displays status information for blocks containing status bits. If none of the status bits are set, an
OK
 message appears in this field. Otherwise, a list of the status bits that are set appears here. This list is comprised of the parameter names associated with the status bits, and will typically explain which parameters were configured with invalid values.
Execution Order
Displays the block's execution number if the routine is in a verified state. If the routine is not yet verified, a
Routine not verified
 message appears. Note that this item is read-only.
OK
Click this button to add the selected item in the instruction list to the routine and close the
Function Block Properties
 dialog box.
Cancel
Click this button to cancel any edits you have made and close the
Function Block Properties
dialog box.
Apply
Click this button to accept your changes on the
Alarms
 tab and continue editing in the
Function Block Properties
 dialog box.
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