Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: kolias on February 08, 2017, 06:14:10 PM

Title: Mach3 PWM Settings
Post by: kolias on February 08, 2017, 06:14:10 PM
Reading on the web some say that the Mach3 Motor Tuning and Setup screen has no affect when using PWM and some say to set the Stepsper to 1000, increase the Velocity / Acceleration to maximum and set the Step pulse to 5, Direction pulse to 1. I wonder which one is true

On my PWM system with G540 and a 400Hz / 24K RPM spindle I get the following with my pulley set to min=0 and max=24000, ratio=1

M3S6000 / 188Hz on the VFD, It should be 100Hz
S12000 / 256, it should be 200Hz
S18000 / 324, it should be 300Hz
I didn’t try yet S24000 since the spindle is new and will try this speed later

Should I play with the numbers on the Motor Tuning & Setup page to get the right frequency?
Title: Re: Mach3 PWM Settings
Post by: ger21 on February 08, 2017, 07:08:16 PM
When you do an S12,000, whats the voltage coming from the G540 to the VFD? It should be 5V.
Title: Re: Mach3 PWM Settings
Post by: kolias on February 08, 2017, 07:28:50 PM
Never thought to measure that since the VFD parameter PD070 is set to 0 (10v). I just check it now and I get between G540- terminals 7 & 8 (ACM & Vout)

S12000, 256.6Hz, 4.81v
S6000, 188.6Hz, 2.42v

If you want terminal 9 (Vout from the VFD) where should I connect my meter? Between Terminal 9 and ACM? Not sure here
Title: Re: Mach3 PWM Settings
Post by: kolias on February 09, 2017, 07:48:57 PM
I measure tonight the VFD terminal +10V and I get

S12000, 256.9Hz, 9.89v
S6000, 188.6Hz, 9.89v
Title: Re: Mach3 PWM Settings
Post by: kolias on February 11, 2017, 03:35:05 PM
Looking at the Mach3 manual page 5-17 it says “Define External Activation signals in Ports and Pins and Configure>Output Devices to switch the PWM controller on/off and, if required, to set the direction of rotation.”

I didn’t know that I have to switch the PWM controller on/off and I can’t locate where this setting is.

Anyone knows where this setting is located?
Title: Re: Mach3 PWM Settings
Post by: Tweakie.CNC on February 12, 2017, 01:53:07 AM
Quote
I didn’t know that I have to switch the PWM controller on/off and I can’t locate where this setting is.

Section 5.5.5.2 of the Mach3 manual details the procedure.  http://www.machsupport.com/help-learning/product-manuals/

Tweakie.
Title: Re: Mach3 PWM Settings
Post by: kolias on February 12, 2017, 09:14:59 AM
Thanks Tweakie, all is fine now
Title: Re: Mach3 PWM Settings
Post by: ger21 on February 12, 2017, 10:00:28 AM
Quote
Section 5.5.5.2 of the Mach3 manual details the procedure.

"Details" is a rather strong term for a very vague statement, that probably doesn't apply to 99% of users. :)
Unless I'm missing something.
Title: Re: Mach3 PWM Settings
Post by: ger21 on February 12, 2017, 10:02:44 AM
Quote
Never thought to measure that since the VFD parameter PD070 is set to 0 (10v). I just check it now and I get between G540- terminals 7 & 8 (ACM & Vout)

S12000, 256.6Hz, 4.81v
S6000, 188.6Hz, 2.42v

This would mean that the issue is with the VFD.
Did you resolve this?
Title: Re: Mach3 PWM Settings
Post by: kolias on February 12, 2017, 11:14:13 AM
I agree Gerry, the manual regarding PWM is very vague and it should have more info regarding setting up a PWM or Steps system.

That’s the first time I use PWM but the values of 4.81 and 2.42 I get are pretty close to the recommended values of 5.0 / 2.5 and I would say perhaps my meter been of Chinese origin maybe is not that accurate.

I have read almost all post on this forum regarding PWM and non-have a clear answer, at least to me, how to set it up. The settings on the Motor Tuning page for the spindle have no effect whatever and my conclusion is that you play with the pulley ratio and that’s what I will do today and report back.

Thanks for your help
Title: Re: Mach3 PWM Settings
Post by: ger21 on February 12, 2017, 11:52:38 AM
My understanding is that you're never going to get a 100% correct voltage, but as you say, they are pretty close.
What this means, is that your Mach3 settings are correct, as The G540 is sending the correct voltage to the VFD.
The issue is that the VFD is not giving the correct speed that corresponds to the input voltage.

I've heard that better VFD's allow you to adjust this to compensate for voltage irregularities, but I don't know if yours does.
Title: Re: Mach3 PWM Settings
Post by: kolias on February 12, 2017, 01:44:16 PM
I understand what you are saying Gerry but as I explain below the VFD produces the 400Hz / 24000RPM and varies the speed with the local contro so to my opinion I’m missing a setting somewhere and perhaps this setting is on the VFD.

I first verified that the VFD on local control takes the spindle to 400Hz and it shows RPM=24000. Then changing the VFD to external control (Mach3) and asking for different speeds with different pulley speeds and ratio I don’t get what I want (BTW I deleted the “Liniarity.dat” from the Mach3 Macros folder as I read this file should be deleted and Mach3 will regenerate it)

Pulley min / max 0/24000 ration 1:1
S6000, VFD shows 11299RPM / 186Hz, G540 volts 2.42vdc
S12000, 15398RPM / 256Hz, 4.81vdc

Pulley min max 0/30000 ratio 1:1
S6000, 10492RPM / 174Hz, 1.95vdc
S12000, 13752RPM / 299Hz, 3.85vdc

Changing the pulley ratio to 0.80 does not change the above.

In other words I’m running out of options on how to calibrate the spindle to be “close” to what I’m asking. I will investigate if I’m missing a VFD parameter
Title: Re: Mach3 PWM Settings
Post by: kolias on February 12, 2017, 02:10:01 PM
BTW Gerry I think the VFD only outputs 10vdc (9.89 in my case) and it’s up to G540 to interpolate this voltage and output the correct volts to Mach3. Am I correct?
Title: Re: Mach3 PWM Settings
Post by: NosmoKing on February 12, 2017, 03:11:16 PM
Pin 7,8,9 of the G540 connect to 7 - ACM: 8 - V1: 9 - +10.
The 10v is used by the G540 to power the analogue output of the G540.
And outputs on term 8.
Nosmo
Title: Re: Mach3 PWM Settings
Post by: kolias on February 12, 2017, 03:15:16 PM
Thats correct Nosmo, my wiring is the same
Title: Re: Mach3 PWM Settings
Post by: TOTALLYRC on February 12, 2017, 08:30:41 PM
In other words I’m running out of options on how to calibrate the spindle to be “close” to what I’m asking. I will investigate if I’m missing a VFD parameter
Try going to Function configs and then open the spindle calibration tool. It should allow you to get closer.
Title: Re: Mach3 PWM Settings
Post by: kolias on February 12, 2017, 08:39:18 PM
No idea how to go to Function Config and the manual i have says nothing about it. Can you explain how?
Title: Re: Mach3 PWM Settings
Post by: kolias on February 13, 2017, 09:54:30 AM
On the Mach3 main screen at the bottom right there is the “Spindle Speed” controls. Under the Reset button there is the RPM box. Why I don’t see a value there when my spindle runs?

I only see the RPM at the bottom in the Spindle Speed box
Title: Re: Mach3 PWM Settings
Post by: TOTALLYRC on February 14, 2017, 05:45:55 PM
At the top left of the Mach3 screen it says file, then Config, then Function Config's. click on function Config's. The first option is calibrate spindle.


HTH

Mike

Title: Re: Mach3 PWM Settings
Post by: Davek0974 on February 15, 2017, 02:24:44 AM
I thought spindle calibrate only had an effect if there was encoder feedback of the actual spindle speed i.e Mach3 was controlling the Pid loop???
Title: Re: Mach3 PWM Settings
Post by: kolias on February 15, 2017, 09:49:09 AM
At the top left of the Mach3 screen it says file, then Config, then Function Config's. click on function Config's. The first option is calibrate spindle.
HTH Mike

That's pretty good, now have to find out if its only for pid as Dave says and look in the manual to see what I have to do
Thanks
Title: Re: Mach3 PWM Settings
Post by: kolias on February 19, 2017, 11:07:34 AM
Regarding the Function Config / Calibrate Spindle I was told that’s if you have PID.

I have ordered a RS485 adapter and when I get it I will try the Mach3 Plugin which as I understand gives good results for PWM systems.

Today I set my pulley max to 6000 RPM (ratio is always 1:1) and when I do M3S6000 the spindle went to 23479 RPM / 391Hz, the voltage from G540 to VFD was 9.53v

Changing the pulley max to 24000 RPM I get with M3S6000 spindle = 11300 RPM / 188Hz / 2.29v

It looks like the pulley setting has a big effect on the spindle but I don’t know the relation. I find it strange that when I set the pulley to max 6000 RPM the spindle will go to almost 24K RPM, 400 Hz and almost 10v. I other words increasing the pulley max. decreases the spindle RPM.

Any ideas?