Mitsubishi Q Series User Manual

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MELSEC-Q
1 GENERAL DESCRIPTION
1.2 The PID Control System
(1) The PID control system
Figure 1.2 indicates the system configuration when performing PID control.
Set value data
storage
process value
data storage
PID operation
Sensor
Control
object
Q62HLC
SV
PV
MV
Manipulated value
data storage
Fig. 1.2 The PID control system
(2) PID control procedure
The PID control is performed in the procedure shown in Figure 1.3 below:
Read the PV value
Perform PID
operation
Output MV
Import a signal from the temperature sensor and write
it to the process value storage area as a PV value.
Perform PID operation using the SV/PV values in the
set value/process value storage area.
Convert MV value obtained by the PID operation
to current output and output it.
Fig. 1.3 PID control procedure
(3) PID control (simplified two-level response selection)
In general, when the P, I, and D constants to improve the "response to the
setting" are set, the "response to the disturbance" degrades by the PID control.
Conversely, when the P, I, and D constants to improve the "response to the
disturbance" are set, the "response to the setting" degrades by the PID control.
In the PID control (simplified two-level response selection) of this module, "fast",
"normal", or "slow" can be selected for the "response to the setting" while the P, I,
and D constants for better "response for the disturbance" are selected.
Response to the change of the set value
Set
value
(SV)
Normal
Fast
Slow
Set
value
(SV)
Response to the disturbance
Fig. 1.4 simplified two-level response selection

Mitsubishi Q Series Specifications

General

Brand	Mitsubishi
Model	Q Series
Category	Control Unit
Language	English