Rockwell Automation 20B PowerFlex 70, PowerFlex 700 Reference Manual - Manual (Page 143)

Process PI Loop
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013 143
undesirable and sudden operation if the system were switched to manual
operation and back. Resetting the integrator eliminates this windup.
NOTE: In the PowerFlex 70, once the drive has reached the
programmable positive and negative PI limits, the integrator stops
integrating and no further “windup” is possible.
3. [PI Status] parameter is a set of bits that indicate the status of the process PI
controller
•
Enabled – The loop is active and controlling the drive output.
•
Hold – A signal has been issued and the integrator is being held at its
current value.
•
Reset – A signal has been issued and the integrator is being held at zero.
•
In Limit – The loop output is being clamped at the value set in [PI Upper/
Lower Limit].
PI Reference and Feedback
The selection of the source for the reference signal is entered in the PI Reference
Select parameter. The selection of the source for the feedback signal is selected in
the PI Feedback Select parameter. The reference and feedback have the same
limit of possible options.
PowerFlex 70 options include DPI adapter ports, MOP, preset speeds, analog
inputs and PI setpoint parameter. In the PowerFlex 700, options are expanded to
also include additional analog inputs, pulse input, and encoder input.
The value used for reference is displayed in PI Reference as a read only parameter.
The value used for feedback is displayed in PI Feedback as a read only parameter.
These displays are active independent of PI Enabled. Full scale is displayed as
±100.00.
Refer to Analog Input Configuration on page 19 .
PI Reference Scaling
The PI reference can be scaled by using [PI Reference Hi] and [PI Reference Lo].
[PI Reference Hi] determines the high value, in percent, for the PI reference. [PI
Reference Lo] determines the low value, in percent, for the PI reference.
The PI feedback can be scaled by using [PI Feedback Hi] and [PI Feedback Lo].
[PI Feedback Hi] determines the high value, in percent, for the PI feedback. [PI
Feedback Lo] determines the low value, in percent, for the PI feedback.
Vector