SJ100/L100 / PID / 4

SJ100/L100 series inverters have integrated PID control, which is indicated by the dotted line in Fig. 2-1.

You can use PID control by setting a target value and providing a feedback signal.

The example in Fig. 2-2 shows a connection diagram for ventilation flow control in a fan application.

(1) P : Proportional Control

This controls the output frequency so that output frequency and deviation have a proportional relation.

The coefficient of deviation and output frequency (expressed in %) is called Proportional Gain (Kp). This

parameter can be set under function [A71].

Fig. 2-3 shows the relationship between deviation and output frequency. If you set a high value of Kp,

the response of the system to a rapid change in deviation is fast. However, if Kp is too high, the system

can become unstable.

SJ100/

L100

Target Feedback Transducer
(DC0-10V, 4-20mA)
Flow volume sensor

Fan

Motor

100% of output frequency of above figure is equivalent to maximum output frequency.

Kp can be chosen between 0.2 and 5.0 in function [A71].

4 bit of digital
input signal
Fig. 2-3 Relation between deviation and output frequency of SJ100/L100
Max. frequency <---
100
75
50
Output
frequency
(%)
25
100
75
50
25
0
Deviation(%)
K
p
=2
K
p
=1
K
p
=0.75
Kp=0.5
Kp=0.25
02
5
0
.
.
Kp