To determine whether lost steps are caused by the stepper motor itself or by mechanical issues in the equipment, perform the following test.
Important: Before beginning, rule out electrical interference (EMI) as a potential cause. Ensure that the motor and driver cables are properly grounded and shielded, and that they are routed away from high-power equipment. If EMI is present, it can cause lost steps and invalidate the test results below.
Test Procedure
- In your controller, set the acceleration, deceleration, and operating speed to low values.
- Create a simple motion program that moves the motor back and forth.
- Mark the motor's initial position (e.g., place a mark on the motor shaft and a corresponding reference mark on a fixed surface such as the mounting bracket).
- Run the program continuously for several hours.
- After the run, check whether the shaft mark still aligns with the reference mark.
Interpreting the Results
If there is no deviation: The motor is able to return to its initial position consistently, which indicates that the motor and driver are functioning correctly. The lost steps observed during normal operation are likely caused by speed or acceleration settings that are too high, causing the motor to operate in a region of its torque–speed curve where available torque is insufficient. To resolve this, try reducing the motor speed and acceleration, or replace the motor with a higher-torque model.
If there is a deviation: The motor is not returning to its initial position, which suggests a problem with the motor or the driver. Swap in a known-good motor or driver one at a time to isolate whether the fault lies with the motor or the driver.
Additional Note on Electrical Interference
If you have not already done so, verify that the equipment is not affected by EMI. Proper grounding and shielding of the motor and driver cables, as well as maintaining adequate distance from high-power equipment, can help determine whether interference is contributing to the lost-steps issue.