Santerno Sinus Penta - VOLTAGE DROP COMPENSATION - FEEDBACK FROM TWO ANALOG INPUTS

SINUS PENTA
PROGRAMMING GUIDE
408/486
46.5.2. VOLTAGE DROP COMPENSATION - FEEDBACK FROM TWO
ANALOG INPUTS
Assume that two +/–10V voltage signals proportional to the instantaneous voltage of two phases downstream of the
filter are present and that 100V correspond to 1V. Those signals are linked to analog inputs AIN1 and AIN2. Assume
that the rated motor voltage (C019) is 400V. If the voltage downstream of the filter is a sinusoidal voltage, the voltage
sinusoids will be 400*SQRT(2) = 565V at a rated voltage of 400Vrms. The amplitude of signals AIN1 and AIN2, damped
1:100, will be 5.65V, i.e. within the allowable range.
Set the following in the PID CONFIGURATION MENU:
C285
Selection of PID Reference 1
9: V out
C288
Selection of PID Feedback 1
13: V out measured
C291
PID Operation
1: Normal
C294
PID Feedback
3: Add Voltage Output
Set the following in the INPUTS FOR REFERENCES MENU:
P055
Type of Reference for AIN1 Input
0: +/–10V
P057
Ref. Max. Value Limits for AIN1 Input
8.0V
P060
Type of Reference for AIN2 Input
0: +/–10V
P062
AIN2 Input Value Producing Maximum Reference
8.0V
Set the following in the PID PARAMETERS MENU:
P236
Max. PID Output
100.00%
P237
Min. PID Output
0.00%
P240
Proportional Coefficient Value
1.000
P242
Integral Time
Disabled
P245
PID Reference Min. Value
0.00%
P246
PID Reference Max. Value
200.00%
The selection criterion of parameters P057 and P246 is the following as per the hypothesis above: 8Vrms in AIN1 and
AIN2 correspond to 800Vrms, i.e. 200% of the rated motor voltage set in C019. The upper limit for parameter P246 is
200%, so P057 = 10.00V, P247 = 1000/400 = 250%, equivalent from a numerical point of view, would not be possible.
The compensated output voltage will be as follows:
Vout = Vd + Vmot*PIDout, where:
Vd is the voltage delivered without compensation,
Vmot is the rated motor voltage (C019),
PIDout is the PID output, given by (Vref - Vfbk)/Vmot.