# PID Adjust

This chapter explains position-loop, speed-loop, speed-feedforward, bus-adjusted PID, speed/position excitation, and filter settings in the PID Adjust window. Retain the last recoverable stable parameter set before tuning.

## Before You Begin

Item | What to Check
--- | ---
Connection target | The current connection ID in the main window matches the target drive, and no other master is modifying the same device.
Mechanical state | Before working with PID, filters, the current loop, or excitation, make sure the motor is stopped, the load is supported, and personnel are clear of the mechanism.
I/O wiring | Before changing input/output functions or inversion, verify terminal wiring, external safety circuits, limits, the brake, and external control logic.
Parameter source | PID, current-loop, and filter parameters must come from project delivery documents or field commissioning records. Do not copy parameters from an unknown device.

High-risk operation: Switching outputs, mapping input/output functions, configuring STO, applying PID parameters, running speed/position/current excitation, or reversing current direction can change device response or trigger mechanism motion. Do not experiment until field conditions are confirmed.

## Recommended Procedure

1. Confirm that the main window is connected to the target drive and verify the current connection ID.
2. Read or re-read the current parameters after opening a window; do not overwrite field values directly.
3. Change only one area at a time, such as I/O mapping, PID parameters, or current-loop parameters.
4. After clicking Apply, check that status, position, speed, current, temperature, and I/O indications are as expected.
5. After confirming normal operation, follow the project process to decide whether to save to Flash.

Before tuning closed-loop parameters or running excitation, confirm that Motor, Feedback, and Control are configured correctly, and retain the last stable parameter set for recovery.

## PID Adjust

Use the PID Adjust window to adjust the position loop, speed loop, speed feedforward, and bus-adjusted PID, and to run speed/position excitation and update filters.

Parameter/Area | Description | Recommendations
--- | --- | ---
Pos Loop Gain: | Affects position-control stiffness and position-error convergence. | Make small adjustments according to the project procedure, then validate each change at low speed over a short travel.
Speed Loop Gain: | Affects speed response and tendency to vibrate. | If noise, vibration, or overshoot occurs, stop increasing the parameter and return to a known stable value.
Speed Loop Integral: | Affects steady-state speed error and low-speed holding capability. | After adjusting, observe low-speed stability and overshoot. Avoid large single-step changes.
Speed Feed Factor: | Adjusts speed feedforward. Start from 0 by default; the window displays it as a percentage. | Adjust only when optimizing the motion profile and following error. Do not save a temporary value as a delivery parameter.
Bus Adjust PID: | Determines whether PID parameters are adjusted by eTuner or an external bus. | If an external master maintains PID parameters, do not use eTuner to modify them. Confirm the current control source and commissioning process before switching.
Excit Speed: | In count/s. A commonly used frequency is 1 Hz to 2 Hz. | For engineering commissioning and response observation only. Verify the motion range, emergency-stop method, and last stable parameters before proceeding.
Excit Position: | The excitation displacement is normally a small proportion of excitation speed; a commonly used frequency is 0.5 Hz to 1 Hz. | For engineering commissioning and response observation only. Verify the current position, travel range, and limits before proceeding.
Refresh | Refreshes the current drive parameters. | Read the current values before making changes to avoid overwriting a verified field configuration.
Apply | Writes the parameters in the current window. | Before applying, verify the connection ID, device state, and parameter source. After applying, monitor status and position error.

There is no universal PID parameter set for every device. The same parameter may behave differently with different loads, mechanisms, encoders, and firmware.

## Speed/Position Filters

Area | Description | Recommendations
--- | --- | ---
Velocity Filter | Switch to the speed-filter area in the PID Adjust window to view and adjust speed-related filters. Project documentation commonly specifies a low-pass frequency around 600 Hz to 800 Hz. | Change one item at a time according to commissioning records. Do not make large simultaneous changes to multiple filter groups.
Position Filter | Switch to the position-filter area in the PID Adjust window to view and adjust position-related filters. Project documentation commonly specifies a low-pass frequency around 300 Hz. | After changing it, observe position error, response delay, and motion smoothness.
Update Filter | Updates the filters using the current filter settings. | Verify the parameters before updating. Do not proceed directly to high-speed or heavy-load motion afterward.

Filter parameters affect response speed, noise suppression, and stability. If following slows or vibration or abnormal noise occurs, restore the last stable configuration.

## Excitation Risks

Excitation Type | Window | Risk
--- | --- | ---
Excit Speed | PID Adjust window | Sends speed-excitation commands to the device. Make sure the motor can move safely before proceeding.
Excit Position | PID Adjust window | Sends position-excitation commands to the device. Verify the current position, travel range, and limits before proceeding.
Excit Current | Current Circuit window | Sends current-excitation commands to the device. Verify the motor, load, emergency stop, and external safety measures before proceeding.

Excitation is for commissioning and response observation, not normal operation. Do not run excitation without a defined commissioning procedure, parameter range, and stopping method.

## Terminology

Term | Meaning | Why It Matters
--- | --- | ---
Inversion | Changes which logic level is treated as active for an input or output. | Incorrect inversion of a limit, enable, brake, or safety-related signal can make field behavior opposite to expectations.
STO | Input configuration related to Safe Torque Off. | This affects the safety circuit and must not be tested casually as an ordinary I/O function.
PID parameters | Closed-loop parameters that affect response speed, stiffness, steady-state error, and tendency to vibrate. | Unsuitable parameters may cause overshoot, vibration, impact, or following errors.
Filter | Filter settings for speed- or position-related signals. | Too little filtering may not suppress noise; too much may slow the response.
Excitation | Sends speed, position, or current excitation to observe system response. | Excitation can cause motion or torque changes and must follow a defined commissioning procedure.
Current direction | How the drive interprets current and torque direction. | An incorrect direction may cause abnormal torque direction, commutation faults, or motor instability.

## Troubleshooting

Symptom | Recommended Action
--- | ---
I/O state does not match the external signal | Check wiring, signal levels, inversion settings, input/output function mapping, and the connected device.
External device behaves abnormally after applying I/O settings | Stop commissioning immediately. Check DOut states and external relay or brake connections, then restore the verified configuration.
Vibration or impact after PID adjustment | Stop motion, restore the last stable parameters, and make further adjustments in smaller steps.
Response slows after updating filters | Check the speed/position filter settings for excessive filtering or settings unsuitable for the current load.
Motor behaves abnormally after current-loop changes | Disable the drive and check current KP, current KI, filter coefficient, reverse-current-direction setting, and motor parameters.
Device does not return to the expected state after excitation | Stop further operations, re-read parameters and status, and verify motor enable, motion state, error state, and current control source.