Setting The Pid Constants; Required Settings; Setting Pid Constants With Autotuning - Omron CJ Series Operation Manual

Setting the PID Constants

3-8-2

Required Settings

Example Settings
Starting DM Area Word
3-9

Setting the PID Constants

3-9-1

Setting PID Constants with Autotuning

Using the Autotuning
Function
Starting Autotuning
ON
OFF
The control method, set point, and control sensitivity must be set to use ON/
OFF control.
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 ° .
DM word Setting
D (m+14) Loop 1 control sensitivity
D (m+24) Loop 2 control sensitivity
D (m+54) Loop 3 control sensitivity
D (m+64) Loop 4 control sensitivity
The starting DM Area word (m) for a Special I/O Unit is:
m = 20000 + (100 × unit number)
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.
• 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
Control sensitivity (heating)
PV
Set point
BCD
0000 to 9999
0000 to 9999
0000 to 9999
0000 to 9999
Section 3-9
Setting ranges
Binary
0000 to 270F
0000 to 270F
0000 to 270F
0000 to 270F
57