SX3 spindle speed controller (CNC Mode)

[iGG1e]

I realise this is an old issue, but I'm revisiting it as it is starting to drive me up the wall. Besides that, it does have a future bearing on whether I implement some ideas.

The control of the speed in CNC mode is nothing short of atrocious. Not only does it take an age to spin up, it falls woefully short of the requested speed unless at high RPM’s and after doing a bit of profiling there are large steps in the control range so you get the exact same spindle speed even if you request a different one within about 60RPM of the current speed. Any speed variation depends where you are in the ‘step’ and how close you are to a transition point. They must’ve gone to town on this and used something like a 4bit DAC.

Does anyone know of a third party controller being successfully hooked into the system to replace whatever that East Crystal board is?

Failing that I think the only solution is to junk the supplied electronics and fit a different motor with VFD control. At this moment in time I’m feeling really aggrieved that I’m even considering such a thing due to the fact that I shouldn’t have to as the PAID for package shouldn’t have such fundamental issues!

Any thoughts and ideas are most welcome.

[LeeWay]

I am using a DC-06 board from Homann Designs on my mill. It's not an X3, but is a DC motor. Treadmill motor actually. The controller for it is very similar to what is on the X3. The difference I think is that I can start this motor in high speed. No need to start at slow speed and then increase. There are adjustments on this controller for spin up and down times too.

With a few adjustments made in Mach 3, I get very near perfect on my slow speed and my high speed. 3000 and 6600 RPM. The other ranges vary a little more. Say I set it to 500 RPM. It might do 450 instead. Using the step settings in Mach is how I adjusted this to get the speeds I typically use very close to perfect. Say within 5 to 10 RPM.
That is close enough to perfect for me.

He had=s other boards that may be better suited to the X3. Just drop him an email.
I am sure he can fix you up.

[neilw20]

The existing unit just measures the speed. If it is too slow then it pushes the UP button and waits for a while (beeping to say it is not at the right speed).

Too slow. Push the UP.
Too fast. Push the DOWN.
Stop. Keep pushing the DOWN. That is just plain DUMB.
Reverse. Push DOWN.
Stopped. Who knows. Push reverse.
Sh1T. Too fast, SLOW down.
Ahh, bugger. Start again.
It is ALL just DUMB.
The PWM and direction signal from Mach3 are perfect.

The front panel button operates a 'digital potentiometer chip' using the up and down button and the DC out of this PCB to control the motor is reasonable.
When I get time, I am going to make a new interface between the PWM and the motor controller. With a bit of coaxing the controller could be made to run a bit faster, but that's another story. With an ATC it needs to work better.
When the current limit is hit the spindle stops dead. OK.
But it DOES NOT hit the E-S or disable the feed, so we end up with a cutter smashing plow.
Watch this space in the NEW YEAR. I am too busy to fix my own at the moment.

[iGG1e]

Thanks for the info guys. I'm going to take a closer look at just how this thing is all hooked together and see if I can't make it do what it's supposed to do.

[neilw20]

Re-write the Chines Atmel CPU code from scratch, or start again. EC got it wrong and SIEG won't talk to Syil.

[iGG1e]

Yes having been discussing it and it all depends on whether we can be bothered (technical capabilities aren't the issue and various Atmel's have been used previously) trying to work with existing flaky designs or just junking the entire lot.

Shame I don't live in the States...I'd be staring at a Tormach instead of a red coloured turd.

[neilw20]

It will work OK if we junk the push button strategy. That's what is stuffed.
You can feed a DC speed reference to the BLDC board, taking care of bitey mains on the early version and being careful on the later one.
The early one was a better controller using a motorla MC33033 which has to better than their Atmel attempt. (the piggy back board).
It should current limit and go soft before stopping dead. More dumb logic.

[ataxy]

hey neil does east crystal have a website.. i am trying to find whats the torque of the motor in the syil X4 but on the motor all there is, is a part number that gives no clue about the torque

[smallblock]

Its been said before, but you should just dump all the Chinese electronics and start fresh. Anyone can deal with the mechanical issues of Chinese machines, but electronics problems will turn your hair gray.

[neilw20]

They have a website, but all they seem to do is make custom stuff to customers specs. The problems began and are caused by (IMHO) the mechanical people not providing adequate specs to EC, and EC just doing the minimum to make it appear to work. EC can do good work. eg the drivers, but like all modern contract manufacturers do just enough to meet the customer spec and do not question the customer spec unless they can make more money.
They look at spec.
Will it work?
Yes.
If we tell the customer his shortcomings will we make more on the final production runs. No. bugger all.
Do we want to do extra engineering. No.
OK it works.

I get into trouble trying to supply quality.
Will it make more money. NO.
Well that's good enough. They only pay us to do job to spec.
We will sell them them that idea in the next model and charge development again.
That is the way it works now.

[ataxy]

eh ok do you have there url cuz when i search google for east crystal i get nothing

[neilw20]

Google East Crystal
look down the list
http://www.ecec.com.cn/english/
Good luck..