Omron SYSMAC CS Series Instruction & Reference Manual page 604

3. Instructions
• Integral constant (Tik) = &9999 (no integral operation) if the integral constant (Tik) is less than 1 as a
result of AT execution with integral and derivative unit = "1: Sampling period multiple". Likewise,
differential constant (Tdk) = 0 (no derivative operation) if the derivative constant (Tdk) is less than 1
as a result of AT execution with integral and derivative unit = "1: Sampling period multiple".
Hint
• The PIDAT(191) instruction is the same as the PID(190) instruction with the added autotuning (AT)
function, so the PID control operations are identical. Refer to 3-19-1 PID CONTROL: PID(190) for
details on PID control operations and examples.
• PIDAT(191) is executed as if the execution condition was a STOP-RUN signal. PID calculations are
executed when the execution condition remains ON for the next cycle after C+11 to C+40 are
initialized. Therefore, when using the Always ON Flag (ON) as an execution condition for
PIDAT(191), provide a separate process where C+11 to C+40 are initialized when operation is
started.
Precautions
• If PIDAT(191) is used between IL(002) and ILC(003), between JMP(004) and JME(005), or in a
subroutine, operation will not be consistent depending on the input condition.
• A PID parameter storage word cannot be shared by multiple PIDAT instructions. Even when the
same parameter is used in multiple PIDAT instructions, separate words must be specified.
• When changing the PID constants manually, set the PID constant change enable setting (bit 1 of
C+5) to 1 so that the values in C+1, C+2, and C+3 are refreshed each sampling period in the PID
calculation. This setting also allows the PID constants to be adjusted manually after autotuning.
• Of the PID parameters (C to C+38), only the following parameters can be changed when the
execution condition is ON. When any other values have been changed, be sure to change the
execution condition from OFF to ON to enable the new settings.
• Set value (SV) in C
(Can be changed during PID control only. An SV change during autotuning will not be
reflected.)
• PID constant change enable setting (bit 1 of C+5)
• P, I, and D constants in C+1, C+2, and C+3
(Changes to these constants will be reflected each sampling period only if the PID constant
change enable setting (bit 1 of C+5) is set to 1.)
• AT Command Bit (bit 15 of C+9)
• AT Calculation Gain (bits 0 to 14 of C+9) and Limit-cycle Hysteresis (C+10) (These values are
read when autotuning starts.)
PID Parameter Settings
Control
Item
data
C Set value (SV)
C+1 Proportional band
C+2 Tik
Integral Constant
C+3 Tdk
Derivative Constant
570
Contents
The target value of the process being controlled.
The parameter for P action expressing the
proportional control range/total control range.
A constant expressing the strength of the integral
action. As this value increases, the integral
strength decreases.
A constant expressing the strength of the
derivative action. As this value increases, the
derivative strength increases.
Setting range
Binary data (of the same number of bits as
specified for the input range)
0001 to 270F hex (1 to 9999);
(0.1% to 999.9%, in units of 0.1%)
0001 to 1FFF hex (1 to 8191);
(9999 = Integral operation not executed)
(See note 1.)
0001 to 1FFF hex (1 to 8191);
(0000 = Derivative operation not executed)
(See note 1.)
CS/CJ/NSJ Series Instructions Reference Manual (W474)
Change with ON
input condition
Allowed
Can be changed
with input condition
ON if bit 1 of C+5 is
1.