GaryS
Member
A couple of things
I see the encoder is drawn as a differently line driver output but if you look at the drawing it shows a pull up resister on the output ( resistor connected to the V supply )
That’s typically and open collector driver configuration. Open collector drivers as prone to noise particularly at high frequencies.
I noticed you said that if you turn it by hang the counts are dead on but if driven the counts are off.
Is motor driven from a VFD if so it could be generating noise in the encoder lines.
Even with shielded cable it can happen, try to change the carrier frequency of the VFD a small change can make a difference
Check the grounding on the system
Check the grounding on the encoder cable shielding
We need to have more information
The encoder used
As wired drawings not the speck drawings
I see the encoder is drawn as a differently line driver output but if you look at the drawing it shows a pull up resister on the output ( resistor connected to the V supply )
That’s typically and open collector driver configuration. Open collector drivers as prone to noise particularly at high frequencies.
I noticed you said that if you turn it by hang the counts are dead on but if driven the counts are off.
Is motor driven from a VFD if so it could be generating noise in the encoder lines.
Even with shielded cable it can happen, try to change the carrier frequency of the VFD a small change can make a difference
Check the grounding on the system
Check the grounding on the encoder cable shielding
We need to have more information
The encoder used
As wired drawings not the speck drawings