Encoder Issue (Siemens Step 7 FM350-1)

[CallumMacEwen]

Hi All,

First time I have ever worked with encoders and I am having a slight issue. The encoder is set up counts up and down and works well for the most part.

Every now and then though when the motor stops the encoder will still increase.

I have verified that the motor has stopped and I have checked the voltage coming from the encoder and it is not pulsing.

Does anyone have any idea why this might be happening?

 

[L D[AR2P#0.0]]

What encoder connections have you got and how have you configured the FM350? If you have pulse and direction signals, then if the motor stops on an encoder edge you will get counts if there is any vibration.

 

[JesperMP]

What kind of encoder ?
If it is a full quadrature encoder with A/B signals, then it should be impossible for the count value to creep even if the encoder is on the edge of changing status.
I think also a half quadrature encoder is immune against this.