Lenze 8200 Frequency inverters - Manual (Page 173)

Configuration
8200SHB0199 7-36
Influence PID controller When using a process control with frequency precontrol (C238 = -1-), the control factor is very
important.
- The control factors is calculated from the difference of the values under C050 and C051.
- The control factor determines the influence C074 of the PID controller.
- The influence (C074) refers to f
dmax
(C011).
- C074 influences the stability of the control circuit. It should be set to a value as low as possible.
The influence C074 [%] is calculated as follows:
Influence [%] C050
C051
C011
ô 100 %
Example
The influence is to be calculated for the following values:
C011 = 50 Hz, C050 = 53 Hz, C051 = 50 Hz
6 %
53 Hz 50 Hz
50 Hz
ô 100 %
- Set the influence so that the output of the process controller covers the calculated value in every
operating point.
- For this example (influence = 6 %) set for instance C074 = 10 %. This is a guide value and
includes tolerances which must always be considered.
- If the influence (C074) is too high, the control circuit may become instable.
Additive influence of the process
controller Conditions:
- C051 = Positive actual value
- C181 = Select positive setpoint
- C238 = -1- (with frequency precontrol)
- Potentiometer connections of the dancer
- End (E) = + 10 V
- Beginning (A) = GND
The direction of control action of the process controller output is added to the main setpoint.
Example of a dancer control with additive influence
of the process controller
M
3~
82XX V20
3
V
T
A
+10 V
0 V ... 10 V
~ V1
V1 V2
S
E
Function:
1.The dancer deflects to the bottom.
(V
T
decreases)
2.V2 increases.
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