PLC Simulator
F-71–F-72 · vendor-neutral function

VFD PID Control for Pumps and Fans

A drive PID function compares a process setpoint with transmitter feedback and continuously changes motor frequency to reduce the error.

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Why it matters

The behavior behind the parameter.

Built-in PID can regulate pressure, flow, level or temperature without a separate PLC loop. It must still be commissioned for feedback scaling, action direction, limits, tuning and sensor-loss behavior.

  • PID output becomes the speed reference.
  • Proportional gain changes immediate response; integral action removes steady error.
  • Minimum speed, sleep/wake and feedback-loss policy protect the process.

Interactive proof

Test vfd pid control for pumps and fans in three passes.

Keep the motor, load and starting condition constant. Change one function at a time, then use the electrical and mechanical evidence to explain the result.

  1. 01

    Select the fan or pump and choose PID reference.

  2. 02

    Move the setpoint and watch process value, error and PID output frequency.

  3. 03

    Change gain or integral time one at a time and compare settling and overshoot.

Load F-code F-71–F-72 in the function lab

Evidence to watch

The function is proved by changed behavior, not by a parameter value alone.

  • Setpoint and scaled process value
  • PID error and output frequency
  • Minimum/maximum clamp and sensor health

Common commissioning mistakes

These errors can make a healthy drive appear faulty or create a misleading test.

  • Tuning before confirming transmitter scaling and action direction.
  • Using excessive integral action to chase a slow process.
  • Ignoring minimum cooling or flow requirements at low speed.

Primary technical references

Transfer the concept; verify the exact drive.

This guide uses vendor-neutral terminology. For real equipment, use the manual for the installed model, option cards and firmware, plus the machine risk assessment and approved commissioning procedure.

Rockwell PowerFlex 520-series user manualSiemens SINAMICS G120 function manualDanfoss VLT AutomationDrive programming guideABB ACS580 manual directory

Related VFD functions

F-23

VFD Speed Reference Sources

The speed reference is the requested output frequency or process demand. It can come from the keypad, 0–10 V, 4–20 mA, preset speeds, a motorized potentiometer, PID output or a fieldbus word.

Read and test F-41

VFD Current Limit and Stall Protection

Current limiting caps drive output current and therefore available motor torque. The drive may slow or extend acceleration instead of immediately tripping when the load demand reaches that limit.

Read and test F-21

V/Hz vs Sensorless Vector VFD Control

V/Hz control applies a frequency-to-voltage profile and is simple and robust. Sensorless vector control uses a motor model to regulate flux and torque more accurately, especially at low speed and changing load.

Read and test

From explanation to evidence

Change the function and watch the motor respond.

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