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Words
14
Manual Command
(Address+13)
Set to the current CV output while the PID block is in Automatic
mode. When the block is switched to Manual mode, this value is used
to set the CV output and the internal value of the integral term within
the Upper and Lower Clamp and Slew Time limits.
15
Control Word
If the Override bit (bit 0) is set to 1, the Control Word and the internal
(Address+14)
SP, PV and CV parameters must be used for remote operation of the
PID block (see below). This allows a remote operator interface device,
such as a computer, to take control away from the application
program.
Control Word is a discrete data structure with the first five bit
positions defined in the following format:
Word
Bit
Value
0
1
1
2
2
4
3
8
4
16
16
Internal SP
(Address+15)
Tracks the SP input. If Override = 1, must be set externally to solve the
PID algorithm using an alternate SP value. The original SP value is
maintained until overwritten.
17
Internal CV
(Address+16)
Tracks CV output.
GFK-2950C
Parameter/Description
If you do not want to allow remote
operation of the PID block, make
sure the Control Word is set to 0. If
the low bit is 0, the next 4 bits can be
read to track the status of the PID
input contacts as long as the PID
Enable contact has power.
Status or
Function
External Action if Override bit is set to 1:
If 0, monitor block contacts below. If 1, set
Override
them externally.
Manual
If 1, block is in Manual mode. If other
/Auto
numbers, it is in Automatic mode.
Should normally be 1. Otherwise block is
Enable
never called.
UP
If 1 and Manual (Bit 1) is 1, CV is incremented
/Raise
every solution.
DN
If 1 and Manual (Bit 1) is 1, CV is decremented
/Lower
every solution.
February 2018
Chapter 7. PID Built-In Function Block
Caution
Low Bit
Range
Units
CV
Tracks CV in
Counts
Auto or sets
CV in Manual
Maintained
Boolean
by the CPU,
unless bit 0
(Override)
is set to 1.
Set and
Non-
maintained
configurable,
by the CPU,
unless bit 0
unless bit 0
(Override) of
(Override) of
Control
Control Word
Word is set
is set to 1.
to 1.
Set and
Non-
maintained
configurable.
by the CPU.
351
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