Rockwell-automation 20B PowerFlex 70, PowerFlex 700 Reference Manual Uživatelský manuál stáhnout pdf (Strana 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

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Rockwell-automation 20B PowerFlex 70, PowerFlex 700 Reference Manual Uživatelský manuál Strana 143