Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 811

Data Control Instructions
Description
772
Area
EM Area with bank
Indirect DM/EM
addresses in binary
Indirect DM/EM
addresses in BCD
Constants
Data Registers
Index Registers
Indirect addressing
using Index Registers
When the execution condition is ON, PIDAT(191) carries out target value fil-
tered PID control with two degrees of freedom according to the parameters
designated by C (set value, PID constant, etc.). It takes the specified input
range of binary data from the contents of input word S and carries out the PID
action according to the parameters that are set. The result is then stored as
the manipulated variable in output word D.
The parameter settings are read when the execution condition turns from OFF
to ON, and the Error Flag will turn ON if the settings are outside of the permis-
sible range.
If the settings are within the permissible range, PID processing will be exe-
cuted using the initial values. Bumpless operation is not performed at this
time. It will be used for manipulated variables in subsequent PID processing
execution. (Bumpless operation is processing that gradually and continuously
changes the manipulated variable in order to avoid the adverse effects of sud-
den changes.)
When the execution condition turns ON, the PV for the specified sampling
period is entered and processing is performed.
PV input (S)
Autotuning
The status of the AT Command Bit (bit 15 of C+9) is checked every cycle. If
this control bit is turned ON in a given cycle, PIDAT(191) will begin autotuning
the PID constants. (The changes in the SV will not be reflected while autotun-
ing is being performed.)
The limit-cycle method is used for autotuning. PIDAT(191) forcibly changes
the manipulated variable (max. manipulated variable
variable) and monitors the characteristics of the controlled system. The PID
constants are calculated based on the characteristics that were observed,
S
En_00000 to En_00000 to
En_32767 En_32729
(n = 0 to C) (n = 0 to C)
@ D00000 to @ D32767
@ E00000 to @ E32767
@ En_00000 to @ En_32767
(n = 0 to C)
*D00000 to *D32767
*E00000 to *E32767
*En_00000 to *En_32767
(n = 0 to C)
DR0 to DR15 ---
---
---
,IR0 to ,IR15
–2048 to +2047 ,IR0 to –2048 to +2047 ,IR15
DR0 to DR15, IR0 to IR15
Parameters (C to C+8)
PID control
Manipulated variable (D)
Section 3-18
C D
En_00000 to
En_32767
(n = 0 to C)
DR0 to DR15
min. manipulated