Hitachi SJ Series, User Manual

Page: 257 / 786

12-10-2
Chapter 12 Inverter Functions
• For PID control, you can select feed-forward
control to attempt stabilizing disturbance in
advance, in addition to feedback control to
stabilize disturbance.
• To control output frequency sent to the motor by
the PID function, selection of PID1-4 and setting of
frequency command are required.
• In the soft-start function, operating normally for a
certain period of distance at the start can raise
output automatically and then shift to PID control.
See "12.10.5 PID Soft-Start Function".
• Sleep mode operation, which is more energy
saving, can be set for when the flow rate or air
volume is increased. See "12.10.6 PID Sleep
Condition Selection Function".
• During PID operation, PID functions are disabled
and normal output is performed with the command
selected as a target value, while the input terminal
function [PID] signal is ON.
• Multi-layer command by PID control command is
feasible.
Basic composition of PID control
• In the case of controlling the motor by PID control,
frequency command destination needs to be set to
PID output.
• The upper/lower limiter function operates for
command frequency by PID output. It does not
operate for PID target value.
e.g.) Follow the steps below to perform simple PID
control by inputting a target value [Ai1] and a
feedback (FB) value [Ai2] from where parameters
are default.
[1]Set [AH-01] to 01 (enable)
[2] Set 15 (PID calculation) to the main speed
command selection [AA101]
[3] Set 01 (Ai1) to the PID1 target value 1 input
destination [AH-07]
[4] Set 02 (Ai2) to the PID1 FB 1 input destination
[AH-07]
[5] Set the PID gain of PID1 to [AH-61] to [AH-63]
[6] Put the command set to operation command
selection [AA111] and start PID control
A !
▼
Target
value
0
～
10V
4
～
20mA
Sensor
Inverter
Normal control
Operation
amount
fs
M ＝
Transducer
Feedback 0 to 10V
4
∼
20mA
+
-
Deviation ε
Kp (1+ +Td
･
S)
1
Ti•S
+
+
Feed-forward Disable
0
∼
10V
4
∼
20mA
-10
∼
10V
PID calculation
Kp: Proportional gain Ti: Integral time Td: Differential time s: Operator
ε
: Deviation
Ki: Integral gain setting (Ki=Ti/Kp) Kd: Differential gain setting (Kd=Kp×Td)