Common problems with pi control, Common problems with pi control -19 – Rockwell Automation 160 SSC Series C FRN 7.xx User Manual

Page 57

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Parameters and Programming

5-19

Common Problems with PI Control

1. Drive direction is incorrectly set for PI control.

Ensure that the drive is operating with the clockwise direction indicator
illuminated.

2. Drive oscillates between 0 and 3 Hz.

• Check direction and polarity of analog input signal.

• Ensure that the drive is operating with the clockwise direction indicator

illuminated.

• Ensure the +10V DC wire is connected to TB3-2 and that the common is

connected to TB3-3.

• Check that parameters P81 - [PI Proportional Gain] and P82 - [PI Integral Gain]

are set to a value other than 0.00.

3. Drive accelerates too quickly resulting in an F05 - OverVoltage Fault.

• Lower P81 - [PI Proportional Gain] below its current value.

• Lower P82 - [PI Integral Gain] below its current value.

• Raise P31 - [Decel Time 1] above its current value.

• Raise P30 - [Accel Time 1] above its current value.

• Evaluate the need for a dynamic brake for the application.

4. Drive will only run off the internal frequency or does not control with the PI

process loop.

• Check that P46 - [Input Mode] is set to 9.

• Ensure that power was cycled for one minute after changing the P46 setting.

• Ensure that there is not a connection between TB3-7 and 8.

5. Nothing works properly.

• Set P56 - [Reset Functions] to 1 and press the Enter key.

• Press the Stop button to clear the F48 - Reprogram Fault.

• Cycle power to the drive.

• Confirm that wiring is correct.

• Reapply power and program according to this procedure.

6. PI does not function with DeviceNet.

• Firmware Version 7.05 and earlier only allows one P46 - [Input Mode] setting

to be active at one time (settings 2 or 6 for DeviceNet or setting 9 for PI).

• It is possible for users of Firmware Version 7.05 and earlier to set up PI

control via an external processor, such as a SLC500. Consult your processor
manual for specific instructions.

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