# Current Circuit

This chapter explains current gain, current integral, filter coefficient, reverse current direction, and current excitation in the Current Circuit window. These settings affect the current loop and torque direction and must not be changed casually by personnel who are not commissioning the system.

## 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.

## Current Circuit

Use the Current Circuit window to configure Current Gain:, Current Integral:, Filter Coefficient:, Reverse Current Direction:, and current excitation.

Parameter/Area | Description | Recommendations
--- | --- | ---
Current Gain: | Current-loop proportional parameter. | Configure according to the drive model and motor parameters. Personnel who are not commissioning the system must not change it.
Current Integral: | Current-loop integral parameter. | Configure according to the drive model and motor parameters. Personnel who are not commissioning the system must not change it.
Filter Coefficient: | Current-loop filter coefficient. | After changing it, monitor current, noise, temperature rise, and operating stability.
Reverse Current Direction: | Changes how the drive interprets current direction. | This affects torque direction or commutation and must be verified while stopped under safe conditions.
Excit Current Type： | Select square wave or sine wave. | Before selecting, confirm the excitation purpose, amplitude, frequency, and field risk.
Excit Current: | Selected as a proportion of continuous current; 80% to 100% of continuous current is commonly used. | Start with a low amplitude in a low-risk condition. Do not excite an unsecured load. Only commissioning personnel may operate this setting according to project documentation.
Excit Frequency: | A commonly used range is 100 Hz to 200 Hz. | Select according to the commissioning objective. After changing frequency, monitor current, noise, and temperature rise.

High-risk operation: Current excitation writes parameters and places the motor in an excitation-related state. Verify the load, emergency stop, mechanical limits, and personnel safety before starting, and check that the device returns to the expected state afterward.

## 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.