Signal length
The signal length is calculated compared to the adjusted period time. In the drawing below, the effect of the
proportional regulator is indicated.
P regulator
0
20
40
60
80
100
0 10 20 30 40 50 60
Kp
Output (%)
4 %
2 %
1 %
0.5 %
In this example, we have a 2 percent regulation deviation and an adjusted value of the Kp = 20. The calcula-
ted regulator value of the unit is 40 %. Now, the pulse length can be calculated with a period time = 2500 ms:
ms
te PERIODDEVIATION
10002500*100/40
*100/
The length of the period time will never be shorter than the adjusted ON time.
9.1.5 Regulator modes
The PID regulators in the AGC 110 can function in three different modes. In the sections below, the three
different modes will be explained. Note that all modes are controlled entirely from M-Logic. The M-Logic inter-
face for controlling the regulator modes is explained in the document "ML-2 application notes M-Logic".
Auto regulation mode
The auto regulation mode looks at the chosen input for the regulator and tries to regulate towards the chosen
reference set point. If the input was a temperature sensor, and the wanted temperature was 50 °C, the refer-
ence set point should be 50 °C. The regulator would then try to achieve and hold a temperature of 50 °C.
Manual regulation mode
When a regulator is in manual regulation mode, the regulator goes into a resting position. The chosen refer-
ence set point in the parameter list is no longer used. Instead the actual value is chosen as a reference set
point for the regulator. The reference set point is then manually changed through two M-Logic increase/de-
crease commands. If an increase or decrease command is given to the regulator, it suddenly sees an error
(error = reference - actual value). The regulator then tries to diminish that error by increasing or decreasing
the output. It can be set by the parameter Man Err Scaling (Manual Error Scaling) how much the increase or
decrease pulse changes the error.
AGC 100 Designer's Reference Handbook
4189340766 UK
PID controller (AGC 110 only)
DEIF A/S Page 147 of 152
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