Rockwell Automation 20B PowerFlex 70, PowerFlex 700 Reference Manual - Manual (Page 170)

Speed Reference
170 Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013
For example, if the following parameters are set:
[Analog In x Hi] = 10 V
[Analog In x Lo] = 0 V
[Speed Ref A Hi] = 45 Hz
[Speed Ref x Lo] = 5 Hz
then the speed command for the drive will be linearly scaled between 45 Hz at
maximum analog signal and 5 Hz at minimum analog signal. See additional
examples under Analog Inputs on
page 22 .
Polarity
The reference can be selected as either unipolar or bipolar. Unipolar is limited to
positive values and supplies only the speed reference. Bipolar supplies both the
speed reference AND the direction command: + signals = forward direction and
– signals = reverse direction.
Trim
If the speed reference is coming from the source specified in [Speed Ref A Sel] or
[Speed Ref B Sel], the a trim signal can be applied to adjust the speed reference by
a programmable amount. The source of the trim signal is made via [Trim In Sel],
parameter 117 and can be any of the sources that are also used as references.
[Trim Out Select], parameter 118 selects which of the references, A/B will be
trimmed.
If the trim source is an analog input, two additional scale parameters are provide
to scale the trim signal.
Figure 36 Trim
Min/Max Speed
[Max Speed]
Maximum and minimum speed limits are applied to the reference. These limits
apply to the positive and negative references. The minimum speed limits will
create a band that the drive will not run continuously within, but will ramp
Trim Enable Select
+
+
+
+
Trimmed
Reference A
Trimmed
Reference B
Reference B
Reference A
Trim
A
B
Both
None