Sampling Cycle - Mitsubishi Electric MELSEC-Q series Programming Manual

Sampling cycle

• A sampling cycle is the cycle in which PID operation is executed. The measurement time for one scan is added to the
measurement time of up to the preceding scan each time a PID operation instruction
value reaches or exceeds the set sampling cycle, the PID operation of the corresponding loop is performed.
• The measured value of the sampling time used for PID operation is truncated to units of 10 ms. For example, if the
sampling cycle setting is 50 ms and the measured value is 57 ms, PID operation is executed with a sampling time of 50 ms.
If the measured value is 64 ms, PID operation is executed with a sampling time of 60 ms.
The sampling cycle is measured when the PID operation instruction is executed.
Therefore, a value smaller than the sequence program scan time cannot be set for the sampling cycle.
If a value smaller than the scan time is set, PID operation will be executed in accordance with the scan time.
*1 The following instructions are available as the PID operation instructions.
S.PIDCONT (incomplete derivative)
PIDCONT (complete derivative)
*2 The following instructions are available as the PID control data setting instructions.
S.PIDINIT (incomplete derivative)
PIDINIT (complete derivative)
5 PID CONTROL PROCEDURE
50
5.1 PID Control Data
*1
is executed. When the cumulative