Nidec Unidrive M600 Series - Page 270

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270 Unidrive M Regen Design Guide
Issue Number: 4
See PID1 Digital Feedback (14.026).
See PID1 Enable Source 2 (14.027).
PID1 alternative feedback and error selection
The description given in PID1 Output (14.001) assumed that PID1 Mode Selector (14.059) = 0 so that PID controller 1 uses its own feedback (FBK1).
It is possible to select alternative configurations that allow various combinations of feedback or error from either PID controller to be used as shown
below.
PID1 Mode Selector (14.059) can be used to select the feedback and error as shown in the table below. It should be noted that PID controller 2 will
operate normally even when its feedback or error has been selected for PID controller 1. However, if PID1 Mode Selector (14.059) is non-zero PID
controller 2 enable is controlled directly by the enable state of PID controller 1.
PID1 Feedback Output Scaling (14.058) can then be used to scale the results. PID1 Feedback Square Root Enable 2 (14.062) can be used in
converting the output of the combined feedback from pressure to flow. It is easier to use a pressure transducer than a flow transducer, and so the
feedback from the transducer needs to be converted from pressure to flow. As flow = Constant x  Pressure the square root function can be used in
the conversion.
See PID1 Feedback Output Scaling (14.058).
14.056 PID2 Digital Feedback
RW Num US

-100.00 to 100.00 %

0.00 %
14.057 PID2 Enable Source 2
RW Num PT US

0.000 to 59.999

0.000
14.058 PID1 Feedback Output Scaling
RW Num US

0.000 to 4.000

1.000
PID1 Mode Selector (14.059) Feedback Error
0: Fbk1 FBK1 ERR1
1: Fbk2 FBK2 ERR1
2: Fbk1 + Fbk2 FBK1 + FBK2 ERR1
3: Min Fbk Lowest of FBK1 or FBK2 ERR1
4: Max Fbk Highest of FBK1 or FBK2 ERR1
5: Av Fbk (FBK1 + FBK2) / 2 ERR1
6: Min Error FBK1 If |ERR1|  |ERR2| then ERR1 Else ERR2
7: Max Error FBK1 If |ERR1|  |ERR2| then ERR1 Else ERR2
14.059 PID1 Mode Selector
RW Txt US

Fbk1 (0), Fbk2 (1), Fbk1 + Fbk2 (2), Min Fbk (3),
Max Fbk (4), Av Fbk (5), Min Error (6),
Max Error (7)

Fbk1 (0)
Value Text
0Fbk1
1Fbk2
2 Fbk1 + Fbk2
3Min Fbk
4Max Fbk
5Av Fbk
6 Min Error
7 Max Error