Articles on: Learning & FAQ

Common Faults and Inspection Methods of Stepper Motor Encoders

During the use of the closed-loop stepper motor, if the encoder is damaged for some reason, the driver will issue a position out-of-tolerance alarm. This article will introduce common causes of encoder damage and how to check the encoder.

Common causes of encoder damage:

Fluctuation of encoder input voltage and current

The signal voltage range supported by our conventional encoders is 5V±0.5V. If the voltage received by the encoder exceeds the maximum voltage allowed by the encoder, the encoder may be damaged.

The signal voltage output by the driver is unstable

Generally speaking, there are components inside the driver to limit the fluctuation of the output signal voltage. However, if the components are damaged, the output signal voltage of the driver may become unstable. Combined with the voltage range of the encoder, if overvoltage occurs, it may cause damage to the encoder's ESD diode.

The encoder cable and terminal are abnormal

The encoder wire inserted into the connector is disconnected, the contact between the connectors is poor, the connection between the connector and the circuit board is weakly soldered, and there is a local short circuit, etc., which may cause the encoder to fail to work properly.

The use environment causes damage to the encoder

If the motor is used in an environment where static electricity exists, the encoder may also be damaged due to the impact of static electricity.

The encoder itself has poor solder

Our motors will undergo factory inspection before leaving the factory, which can largely avoid the occurrence of problematic encoders. However, if the ambient temperature is high during use, it may also cause the components of the encoder to be poorly soldered, causing the encoder to fail to work.

Inspection Method:

Check whether the read head of the encoder is connected.

The pins of the encoder can be measured, as shown in the figure, to measure the A signal and B signal respectively.

Check whether the ESD diode is burned out

You can directly observe whether the diode shows signs of burnout, or you can use a multimeter to measure the resistance value of the diode: first connect the multimeter's meter rod to the position marked in the figure and read the resistance value; then exchange the positions of the meter rod and measure again. If the resistance values ​​measured twice are very different, then there is no problem with the diode; if the resistance values ​​measured twice are 0, it means the diode is damaged.

Observe whether the differential chip of the encoder is burned out

The chip marked in the picture below is the differential chip of the encoder

Measure continuity between connector base pins and cable

If the cable is disconnected or the pins are poorly soldered, it will also appear as an encoder failure.
You can use a multimeter to measure whether there is continuity between the pins of the circuit board and the cable.

Updated on: 28/06/2024

Was this article helpful?

Share your feedback


Thank you!