Specify Configuration; Specify Alarms - Allen-Bradley Logix5000 Reference Manual

Specify Configuration

In this field
PID equation
Control action
Derivative of
Loop update time
CV high limit
CV low limit
Deadband value
No derivative smoothing
No bias calculation
No zero crossing in deadband
PV tracking
Cascade loop
Cascade type
(1) When using the ladder-based PID instruction, if you set MAXO = MINO, the PID instruction will reset these values
to default. MAXO = 100.0 and MINO = 0.0

Specify Alarms

In this field
PV high
PV low
PV deadband
Positive deviation
Negative deviation
Deviation deadband
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Select the Configuration tab. You must click OK or Apply for any changes to
take effect.
Specify
Select independent gains or dependent gains (.PE).
Use independent when you want the three gains (P, I, and D) to operate independently. Use
dependent when you want an overall controller gain that affects all three terms (P, I, and D).
Select either E=PV-SP or E=SP-PV for the control action (.CA).
Select PV or error (.DOE).
Use the derivative of PV to eliminate output spikes resulting from setpoint changes. Use the
derivative of error for fast responses to setpoint changes when the algorithm can tolerate
overshoots.
Enter the update time (.UPD) for the instruction.
Enter a high limit for the control variable (.MAXO).
Enter a low limit for the control variable (.MINO).
Enter a deadband value (.DB).
Enable or disable this selection (.NDF).
Enable or disable this selection (.NOBC).
Enable or disable this selection (.NOZC).
Enable or disable this selection (.PVT).
Enable or disable this selection (.CL).
If cascade loop is enabled, select either slave or master (.CT).
Select the Alarms tab. You must click OK or Apply for any changes to
take effect.
Specify
Enter a PV high alarm value (.PVH).
Enter a PV low alarm value (.PVL).
Enter a PV alarm deadband value (.PVDB).
Enter a positive deviation value (.DVP).
Enter a negative deviation value (.DVN).
Enter a deviation alarm deadband value (.DVDB).
Special Instructions (FBC, DDT, DTR, PID)
(1)
(1)
Chapter 13
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