How to Troubleshoot and Resolve Position Error Alarm in Stepper Drives?

The "position error" alarm is a common fault in stepper systems. It occurs when the driver detects that the difference between the motor's actual position and the commanded position from the control system exceeds the set allowable range (the error counter threshold).

I. Main Causes

1. Mechanical Structure and Load Issues (Most Common)

• Mechanism jam or excessive resistance
• Overload or excessive inertia
• Damaged mechanical components

2. Electrical Connection and Component Issues

• Incorrect wiring or poor contact
• Damaged motor
• Damaged encoder
• Internal driver fault

3. Driver Parameter Settings

• Position error range set too small

II. Troubleshooting Steps

Step 1: Power-off Mechanical and Visual Inspection

• Test without load: Disconnect the motor from the load mechanism.
• If the alarm stops during no-load operation, the problem is 100% on the mechanical load side.
• Check for: jamming mechanisms, poor lubrication, excessive load weight, overly tight or loose timing belts.
• Manual rotation check: With power off, try rotating the motor shaft manually.
• Normal: Should feel smooth with uniform resistance.
• Abnormal: Obvious catching, roughness, or extreme resistance indicates mechanical failure.

Step 2: Power-on Static and Parameter Check

• Verify wiring: Ensure motor wires (A+, A-, B+, B-), encoder cables, and power cables (Vdc, GND) are correctly and securely connected per the manual.
• Position error threshold: Check the current setting. If vibration is present, try increasing this value (temporary solution - root cause is usually mechanical or load-related).

Step 3: Measurement Methods

• Pulse signal measurement: Use an oscilloscope to check the pulse (PUL) and direction (DIR) signals from the controller.
• Verify clean waveforms, correct frequency, and absence of noise.
• Encoder feedback measurement (if supported): For closed-loop steppers, use an oscilloscope to verify proper encoder signal output.

Step 4: Cross-Testing

• Replace motor: Test with a known-good motor of the same model.
• Replace driver: Test with a known-good driver of the same model.
• Replace cables: Replace encoder cables if possible. If unsure, contact technical support.

Summary:

Through systematic troubleshooting, most root causes of position error alarms can be identified and resolved. Always start with mechanical load and basic wiring - the most common culprits - for efficient problem resolution.

Updated on: 28/11/2025