MaslowCNC/GroundControl

Distance Between Motors Calculations Uses Hardcoded 6.35 mm

madgrizzle opened this issue · 8 comments

madgrizzle commented

For those that use different size chains or different sprockets, the distance between motor measurements will be off. The routine currently subtracts a total of 12.7 mm (2x6.35 mm) to account for the two links that are wrapped around the right sprocket. If the chain pitch is different and/or a different number of links are wrapped around the sprocket based upon the number of teeth on the sprocket, this calculation will be off.

blurfl commented

It looks like both measureOneChain.py and measureDistBetweenMotors.py do this. Perhaps they should be using chainPitch from the Advanced Settings as triangularCalibration.py does.

chainPitch = float(self.data.config.get('Advanced Settings', 'chainPitch'))
madgrizzle commented

But how to deal with different number of teeth on the sprocket.. that's the challenge... unless you force the user to only wrap two links.

blurfl commented

Are you using a sprocket with more teeth, having trouble with two links coming adrift?

BarbourSmith commented

Great catch @madgrizzle!!

I think we are safe to assume only two links because that is what the directions say to do, but we should be using proper pitch computations

davidelang commented
madgrizzle commented

I suspect if you are using a high tooth count sprockets, you'll need to clamp the chain to the sprocket to keep it from coming off. Small price for those to pay to keep the method simple.

BarbourSmith commented

Small price for those to pay to keep the method simple.

I couldn't agree more. Let's keep it simple

davidelang commented