Allen-Bradley LOGIX 5000 User Manual

Process Control Instructions
Chapter 1
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018 255
The following diagram shows how the PIDE instruction changes between
Program control and Operator control.
For more i
nformation on program and operator control, refer to
Program/Operator Control.
See also
Program/Operator Control on page 502
The Cascade/Ratio, Auto, and Manual modes can be controlled by a user program
when in Program control or by an operator interface when in Operator control.
The Override and Hand modes have a mode request input that can only be
controlled by a user program; these inputs operate in both Program and Operator
control.
Operating Mode Description
Cascade/Ratio While in Cascade/Ratio mode the instruction computes the change in CV. The instruction
regulates CV to maintain PV at either the SPCascade value or the SPCascade value multiplied
by the Ratio value. SPCascade comes from either the CVEU of a primary PID loop for cascade
control or from the “uncontrolled” flow of a ratio-controlled loop.
Select Cascade/Ratio mode using either OperCasRatReq or ProgCasRatReq:
Set OperCasRatReq to request Cascade/Ratio mode. Ignored when ProgOper,
ProgOverrideReq, ProgHandReq, OperAutoReq, or OperManualReq is set, or when
AllowCasRat is cleared.
Set ProgCasRatReq to request Cascade/Ratio mode. Ignored when ProgOper or
AllowCasRat is cleared or when ProgOverrideReq, ProgHandReq, ProgAutoReq, or
ProgManualReq is set.
Operating Modes

Allen-Bradley LOGIX 5000 Specifications

General

Brand	Allen-Bradley
Model	LOGIX 5000
Category	Controller
Language	English