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Parameters
This section explains the parameters of the PID operation instruction (PID).
Sampling time (T
): (S3)
S
Setting range: 1 to 32767ms
Set the cycle (ms) for PID operation.
• PID control or auto tuning (limit cycle method)
"Operation cycle of programmable controller"<"sampling time"
• Auto tuning (step response method)
1000ms (1s) or more
■Maximum error
The maximum error of the sampling time (T
• When the sampling time (T
The variations of the above maximum error may become a problem. Execute the instruction in constant scan mode or
program it in the timer interrupt routine.
• When the sampling time is shorter than one operation cycle of programmable controller
A PID operation error (9106H) occurs but PID operation is executed assuming sampling time (T
case, use the PID operation instruction in the timer interrupt, and clear (S3)+7 immediately before execution of the PID
operation instruction.
X0
MOVP
PID
(1) Execute (S3)+7 (clear the internal processing register with the pulse conversion command during initial execution of the interrupt routine).
(2) Execute the PID operation.
) ranges from -(1 operation cycle + 1ms) to + (1 operation cycle).
S
) is a small value
S
K0
D107
• • • (1)
D0
D1
D100
D150
• • • (2)
7 APPLICATION INSTRUCTIONS
) = operation cycle. In this
S
733
7.18 PID Instruction
7
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