Erratic Spindle Speed

[groundhog719]

Still trying to get this used X4+ working properly.

Next problem is that the spindle speed is weird. It works OK in manual mode. What follows is using the MDI screen, "M3 Sxxx" commands. Actual speed is read from the LCD on the S4+ (which was earlier checked with an optical tach).

I am using Mach3 (R3.043.022 and tried R3.043.038). Settings; PWM Base:1216, Minimum PWM:0%, Steps Per (Inch):10160, Velocity:59.052, Acceleration:47.24, Step & Dir Pulse:0. Pulley settings; Min:200, Max:3600, Ratio:1.

As you can see from the graph there is no spindle movement until S300. At S300 actual speed goes from 0 to 420 rpm. At S500 the actual RPM drops to 220. From there actual speed is is somewhat linear, but not synced or parallel to the "S" speeds.

Any help or ideas will be greatly appreciated. I will also post this on the Mach3 forum.

[neilw20]

Try disconnecting the power to the stepper drivers and do some spot tests again. Stepper noise could be getting mucking up the PWM signal decoding.
If the graph is different, then PWM filtering is not working very good.
Welcome to the world of Syil spindle control.
My Syil SX3 is not much different to what you have found.

[Ed from NY]

Mine is about the same except that there is no dip in the low RPMs. It is generally on the high side, depending on the range somewhere around 5% to 10%. I stopped chasing my tail on that one because I figure it would not really matter if my inch per tooth was 0.0011 instead of 0.0012.

If I were in your situation I would try to get around 450 to 500 when asking for 500. That will probably offset most of your red curve up a bit, but you would get the use of the 500-700 range, and that is a good thing.

I would not worry about it below 500 RPM. At those speeds it does not have enough torque to be useful.

Someone explained (here or some other place) why this happens with this type of motor/controller. it is some sort of limitation of the type of motor I think (don't ask me more cuz I do not understand it ). The solution was to calibrate the spindle in Mach3. However, that required extra circuitry to provide feedback to Mach3.

I think there is no way to just type in the correction numbers in Mach3, I suppose that would be just too easy *sigh*

I had found a board and all, but then Neil told me "not so nice things" about my chosen supplier's electronics and suggested that I got it from someone in "Australia" of all places I did not look into it further.

See this thread here http://www.cnczone.com/forums/syil_p...tml#post914568

[groundhog719]

Through trial and error I finally settled on 1730 PWM Base which gives me about 50%-60% of requested speed at the low end (225 actual at S400, 240 at S500) and a somewhat straight line to about 98% at 3500 RPM requested. About the best I could do.

So unless someone has any other ideas I guess I'll follow you guys advice and just deal with that. Since it is somewhat linear it will be easier to deal with than before.

I tried to find a pot or something to dial up the bottom end speed. Is there any such adjustment?

Anyhow, thanks a bunch for your help. Don't think I've gotten this dog to hunt yet - but at least I've gotten it's ass out of the pickup!

Groundhog

[neilw20]

I assume it does all that beeping etc when speed is changing?
If it does, stupid interface is just pushing the faster/slower buttons, and stop start.
If it doesn't take a picture of you PCBs. Does it sort of work without big time delays.?
M3 instant start. M4 instant reverse. It should bit almost certainly won't (IMHO)

[groundhog719]

I assume it does all that beeping etc when speed is changing?
If it does, stupid interface is just pushing the faster/slower buttons, and stop start.
If it doesn't take a picture of you PCBs. Does it sort of work without big time delays.?
M3 instant start. M4 instant reverse. It should bit almost certainly won't (IMHO)

I don't have a clue what you are talking about.

[neilw20]

That's OK.
You have a different bob to me, so I know I can't help you much.

[PEU]

you can also try changing the spindle pulleys value, say put there from 200 to 4000, your machine wont go as high but mach3 may show the right speed

[groundhog719]

OK, great.

I played with the pulley speeds and set them back to "0" and "3500" where I once started. I would have saved myself a lot of time and grief had I closed Mach3 each time I changed pulley settings, as I read somewhere that I should do. Just old and stupid I guess (maybe age doesn't have much to do with it).

Anyhow, with PWM Base set at 1730 and the above pulley settings my actual speed is within 10% of requested ("s") speed from 550 to 3400 and very linear. I'm happy!

Thanks again for the help.

Groundhog