forum.cncdrive.com

Looking for an explanation as to why you would want to run in 2X mode vs 4X mode. Does 4X give you more resolution?

Thanks
Derek

I am a newb, so this may not be right, but I've been reading up on encoders in general and seen it mentioned that too high an encoder PPR count can exceed the motion controllers ability to register the pulses.

I'm not sure its relevant here, but maybe?

The microcontroller has to read all encoder edges (4x mode) anyways, but the microcontroller has a QEI (incremental encoder) module built in.
It can do 2x and 4x modes in hardware and so we gave the ability for the user to select it as it is only setting/clearing one bit in the microcontroller configuration.

The microcontroller has to read all encoder edges (4x mode) anyways, but the microcontroller has a QEI (incremental encoder) module built in.
It can do 2x and 4x modes in hardware and so we gave the ability for the user to select it as it is only setting/clearing one bit in the microcontroller configuration.

I hope you realize anyone who understands that response wouldn't be asking the question in the first place:)

I need the "explain it to me like I'm five" answer. So I have US digital incremental encoders with 250 line wheels. I want the most resolution I can get out of it. Would being in 4X mode do that? If yes what possible issues may I run into.

I'm assuming you put time and expense into make it selectable. A better explanation would be great.

Thanks
Derek

The only advantage to have this setting is if you have very low or very high resolution encoder.
With very low resolution 2x mode might not give enough counts per turn to make the motor running smooth enough.
And with very high resolution 4x mode might give too high frequency, higher frequency than what the drive can successfully read.

With your 250 lines encoder in my opinion both settings should work.
I would use 4x mode because that would give higher resolution, smoother running and for controllers like the UCCNC which can output several hundred kHz step frequency it should be not a problem to handle that high encoder counts even if your motor is running fast.