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2M542 & Mach3 settings
« on: July 05, 2016, 12:46:05 PM »
Hi Guys,

I'm trying to set this up for the best performance, it's tricky as reading through pages here on the forum with conflicting info.
So far the settings seems to make the motors really hot, I know this can be normal. An issue is over 200ipm rapids it stalls, also around 100ipm it resonates and stalls.

I'm sure I can get higher rapids and cutting speeds!

My goal is:
Cut Speed: 150ipm
Repeatability 0.015” (+/-)

I have 2M542 drivers with Nema 24 steppers. 48V 7.3A power supply (including another Power supply for the Breakout board w/ UC100 motion controller & Mach3.)
I have a 4th axis and 2 steppers to drive the Y axis, 5 identical motors for all.

Steppers Nema 24:
Voltage: 4.2V
Current: 3.5A
Inductance: 1.6mH
resistance: 1.2

Settings I have at the moment are 2.37A for the drivers, Full current ON : SW4 5 Microstep res, 1000 step/rev

I'm not sure if these drivers can be calculated the same as Geckos for voltage, etc...? Max is 50VDC for them, I'm supplying 48v.

Should I push up to 3.31A for them...? Is my power supply 7.3A enough? Do I calculate 5 motors, @3.31A = 16.55A meaning I need a 20A power supply?
Re: 2M542 & Mach3 settings
« Reply #1 on: July 05, 2016, 08:04:56 PM »
I don't think those drives will like you getting too close to the peak voltage rating of 50v, due to back emf which may kill them (all depends whos drives they are, as there seem to be a few copies about).

In order to remove (reduce) resonance... increase microstepping resolution.

Why did you choose 5 microstep?  You talk about ipm... which normally means you may be running imperial pitch leadscrews.... what pitch are your leadscrews?

Why do you want 200ipm rapids?

What cutting feedrate are you intending to run?


I'd suggest making your drives use 1/2 current when stopped.... and not full current or you will need a larger power supply.... holding current is not normally a problem... as current is more used when the cutter is moving.

It's more about acceleration than high rapid speeds, as if the acceleration isn't there.... rapids mean nothing.

What acceleration are you running.... how did you tune the setup?

Suggest you try using a test gcode file, how big is your table travel?   Set the acceleration lowish, and find the maximum rapid speed, back it off to maybe 75%, then increase the acceleration till it stalls, and back of to 75% and you should be OK to start off with.

Power supply..... leadshine and gecko provide PDFs on power supply selection, do a search for those terms and see what comes up.

What do you intend to cut (material), and with what (cutter material, size and flutes?)

Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”
Re: 2M542 & Mach3 settings
« Reply #2 on: July 05, 2016, 09:25:10 PM »
Thanks for your reply Rob! They are JMC-Motion drives.

I don't remember the pitch by heart, I'll check it in my docs. They were already set at 5 microsteps.

Trying to keep up with orders and squeezing to the max of my machine. 150 to 200 rapids would be nice to cut down on program time.

Ideally I would like to be cutting between 120 to 150ipm. I cut HDU, Acrylic & Polycarbonate, v-carve cedar and occasionally hardwoods / plywood.

My acceleration is 10 at the moment, I've been tweaking that. But I see I should work on Velocity first!

My travel is 40" x 48", 5" Z travel (but I'm happy with my 30 to 45ipm for it). It's really X-Y I'm working on. I will switch to half current.

I was recommended to put fans on the steppers as they run awfully hot.
Re: 2M542 & Mach3 settings
« Reply #3 on: July 05, 2016, 09:25:57 PM »
Here are PDF's of the drivers and motors.
Re: 2M542 & Mach3 settings
« Reply #4 on: July 06, 2016, 01:48:46 AM »
The induction on those drives is quite high, have a look at these similar rated drives.

http://cnc4you.co.uk/resources/Stepper%20Motor%20Nema%2023%2060BYGH401-03%204Nm.pdf

No I don't work 4 the company..... just an example to consider.

You need to consider the parallel wiring arrangement.

I don't know how much you know about induction, but it is basically best to think of it as resistance to current flow that is proportional to motor speed..... faster the motor turns.... the higher the resistance..... a bit like wind resistance in a car..... but sometimes you are driving a sports car, and sometimes a bus.... except both have the same horsepower..... but they won't go as fast as each other.

The technical answer is XL = 2*pi*F*L, where XL is the inductive resistance (in ohms), pi is 22/7, F is the frequency of the input voltage to the drive, and L is the inductance.

Can you provide your steps per unit settings from within Mach, or the leadscrew pitch to consider too, thanks.
Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”
Re: 2M542 & Mach3 settings
« Reply #5 on: July 06, 2016, 06:58:57 AM »
when I spoke about copy drives.... here is a very similar drive to yours with a comprehensive selection manual.  Whilst it is not the same as your drives I would suggest a read as some of the info is still applicable on power supply selections and considerations.
http://www.leadshine.com/UploadFile/Down/M542V2m.pdf

Within this manual is some useful information and considerations of power supply selection which may be worth a read to expand you knowledge in this area:
http://www.leadshine.com/UploadFile/Down/DMShm_P.pdf

and the well known and referenced Gecko information is here:
http://www.geckodrive.com/support/step-motor-basics/power-supply-basics.html

Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”
Re: 2M542 & Mach3 settings
« Reply #6 on: July 06, 2016, 07:28:12 AM »
Thanks Rob, I'll check those out.

At the moment motor settings are:

5080 steps per / Velocity 80.06 (had to set it down, kept loosing steps) / Acceleration 5 / 15 step pulse / 15 dir pulse
Re: 2M542 & Mach3 settings
« Reply #7 on: July 06, 2016, 08:23:54 AM »
Ok, they are 5mm pitch leadscrews, and at 200ipm the drives will be pulsing at 16933 hz, so if you are running mach3 using the parallel port, then set the kernal frequency at 25khz.

I would suggest changing your step and dir pulse settings to 20 and trying it as it will coincide with 25khz kernal speed and still be faster than your 17khz max stepper speed..... nice chunky step

Your acceleration needs to come up in my opinion.... 5"/s/s.... at a cut feedrate of 150"/min .... 2.5"/sec means that your corers will be rounded by up to 0.625" (one axis will slow down on a 90deg corner while the other needs to start accelerating in constant velocity mode..... see one of the other recent posts I've commented on in the last day that has this problem...



Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”
Re: 2M542 & Mach3 settings
« Reply #8 on: July 06, 2016, 08:35:00 AM »
I'm using a UC100 usb motion controller. Not sure if that makes a difference? I'm still learning this and Mach3.

I'll check out your other posts.
Re: 2M542 & Mach3 settings
« Reply #9 on: July 06, 2016, 08:43:12 AM »
It's set to a max step rate of 100kHz for the motion controller