B&R ACOPOSinverter P84, User Manual

Page: 250 / 405

Programming guidelines
250 ACOPOSinverter P84 User's Manual 2.10
Explanation:
Taking into account the inverter settings.
ACC:
DEC:
HSP:
LSP:
1
1
50.0 Hz
0.0 Hz
PIF:
AIC1:
AIV1:
AIV1
CAN
0
PIF1:
PIF2:
PIP1:
PIP2:
0
8192
0
8192
RPG:
RIG:
RDG:
PRP:
7.00
0.01
0.00
0.0 s
POL:
POH:
AC2:
DE2:
-500
500
1
30
The PID output (purple) is calculated with RPG
multiplied by the delta of error:
with delta of error = t - (t-1) -> negative value
because error decreases
t-2
t-1
t
Delta of PID error.
We see that this delta is negative.
In our inverters PID output is calculated by multiplying the RPG-value (gain) with the delta of the error.
Since the PID feedback is linear, the delta value for the fault between t and t-1 will always be the same value. And
even in the case of a positive error, the delta value of the error is negative: t-(t-1) < 0. This negative delta value
of the error is multiplied by a gain (positive) value.
The result: The error is positive, but the delta value of the error is negative. Multiplied by the gain, the PID output
decreases.
If POL = 0, the PID output is limited to 0. If POL permits a negative value, the PID output is negative and the motor
can be run in reverse.