[amaurer]

Here's the situation - I'm trying to setup Mach3 to control a paper handling machine. As the machine is set up the X axis controls the position of the paper cutting carriage, while the Y axis controls the large paper feeding drum. The Y axis is extremely fast but has a LOT of inertia. We're talking >10000 IPM, but takes about 6 seconds to get up to speed.

I can set everything up in Mach3 so that it jogs properly, motors are happy, acceleration good, etc.

Here's the problem... I need continuous motion on the Y axis (so that I don't waste time spinning the drums up and down), but I also have to sneak in some intermittent X motion.

But I couldn't get it to work smoothly. For testing purposes I tried this code to ensure the CV function was working properly (I figure I'll add my X moves to these lines later once the CV settings are good):

G01 Y1000 F15000
G01 Y1000 F15000
G01 Y1000 F15000
G01 Y1000 F15000
etc...

And its not. The Y axis needs about 900" to get up to speed, but with the above code it never does; Mach3 still decelerates the drum between each line. In fact there is not much difference between the behavior in CV mode and that in Exact Stop.

Any ideas how to fix that??

EDIT: Btw I tried various "look ahead" settings from 2 to 500 and didn't notice a change. "Stop CV on Angle" is unchecked.

[ger21]

Set up the Y axis as a step/direction spindle and let it run continuously?

[amaurer]

Set up the Y axis as a step/direction spindle and let it run continuously?

That would be perfect... I didn't know a "step/direction" spindle was a thing.

I don't have an index pulse, can I get away without it since I have step control?

[amaurer]

Well I don't know much about lathe programming, but it looks like there's no way to count the Y axis position if you set it up as a spindle...?

e.g. I need to make my X moves at certain times, e.g. after 1000" are fed... can I do that if the feed is a spindle? I can't find how you'd program that, even if I did add a spindle index.