Omron Sysmac CJ Series, Operation Manual

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57
Setting the PID Constants Section 3-9
3-8-2 Required Settings
The control method, set point, and control sensitivity must be set to use ON/
OFF control.
Example Settings
In this example, ON/OFF control is used for loop 1. The set point is 200
°
C and
the control sensitivity is 2
°
C.
• Turn ON pin 6 of the DIP switch on the front of the Unit. (The new setting
will be read when the power is turned ON.)
• Set the loop 1 SP to 0200 in CIO word n. See 3-7 Setting the Set Point for
details.
• Set the loop 1 control sensitivity to 2
°
C in DM word m+14. (Set D (m+14)
to 0020 if the Unit is set for BCD data; set D (m+14) to 0014 if the Unit is
set for binary data.)
The control sensitivity is set in
°
C or
°
F and the default setting is 0.8
°
.
Starting DM Area Word The starting DM Area word (m) for a Special I/O Unit is:
m = 20000 + (100
×
unit number)
3-9 Setting the PID Constants
3-9-1 Setting PID Constants with Autotuning
The autotuning (AT) function can be used to automatically calculate the opti-
mal PID constants for the set point during operation. This Temperature Con-
trol Unit uses the limit cycle method, which determines the controlled system’s
characteristics by forcibly changing the manipulated variable.
Using the Autotuning
Function
Starting Autotuning • To start autotuning, turn the Start AT Bit from OFF to ON. The Start AT Bit
is in the Special I/O Unit Area words allocated to the Temperature Control
Unit in the CIO Area.
• When autotuning is completed, you must replace the current PID con-
stants with the calculated PID constants in order for the Unit to operate
with the calculated PID constants. The Unit stores the calculated PID con-
stants in the input area of the Operating Parameters in the DM words allo-
cated to the Unit and turns ON the PID Constants Calculated Flag at the
ON
OFF
PV
Control sensitivity (heating)
Set point
DM word Setting Setting ranges
BCD Binary
D (m+14) Loop 1 control sensitivity 0000 to 9999 0000 to 270F
D (m+24) Loop 2 control sensitivity 0000 to 9999 0000 to 270F
D (m+54) Loop 3 control sensitivity 0000 to 9999 0000 to 270F
D (m+64) Loop 4 control sensitivity 0000 to 9999 0000 to 270F