9-2
Example 1: Example 2:
Gain = 1.0 Gain = 2.0
Set-Point = 80% Set-Point = 80%
Feedback = 78% Feedback = 78%
Error = Set-point - Feedback = 2% Error = Set-point - Feedback = 2%
Control Error = Gain x Error = 2% Control Error = Gain x Error = 4%
Please note that an excessive gain can make the system unstable and oscillation may occur.
The response time of the system can be adjusted with the Integral Gain set by parameter 10-06.
Increasing the Integral Time will make the system less responsive and decreasing the Integral Gain
Time will increase response but may result in instability of the total system.
Slowing the system down too much may be unsatisfactory for the process. The end result is that these
two parameters in conjunction with the acceleration (00-14) and deceleration (00-15) times are
adjusted to achieve optimum performance for a particular application.
For typical fan and pump applications a Proportional Gain (10-05) of 2.0 and an Integral Time
(10-06) of 5.0 sec is recommended.
10-03 PID control mode
PID control can be enabled by setting parameter 10-03 to ‘xxx1b’
10-03 PID control mode
Range
xxx0b: PID disable
xxx1b: PID enable
xx0xb: PID positive characteristic
xx1xb: PID negative characteristic
x0xxb: PID error value of D control
x1xxb: PID feedback value of D control
0xxxb: PID output
1xxxb: PID output + frequency command
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