Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: PROTOPLANT on December 01, 2009, 01:02:51 AM

Title: CNC4PC C11G Analog Output Spindle Control
Post by: PROTOPLANT on December 01, 2009, 01:02:51 AM: Hi All,

OK, the next step is to get the spindle working with Mach3, now that I have the index pulse properly setup to read the speed. I have a C11G BOB from CNC4PC and I am not sure how to proceed, here are my problems:-)

1- The VFD I am using ( a 15HP GS3 from automation direct) has an analog output supply of 10V at 20mA max. The C11G has a required input of 12V @50mA. Do I really need another isolated power supply? I feel like I have about enough in that control panel... 24VDC, 24VAC, 12VDC for the drives, 60VDC for the servos, and on and on.....

2- Ive read some not so encouraging things about the C11G's analog capabilities after purchasing it quite some time ago, if I go to the trouble of setting up another PS, will it even work? Has someone out there had success with it? I have 4 of their boards going right now and all the other functionality seems OK, although I had to return one for workmanship issues (pins bent over on IC) and they always look a little funky right out of the box...

Does anyone have any suggestions as to how to proceed? I am seriously considering just switching over completely to Peter Hommans boards and use the C11G in my other lathe which is currently BOB-less.

I've recently received a big order for parts and am feeling the pressure to get this retrofit done, but want it done right :-)

Thanks for any suggestions,
Dustin
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: neptune on December 01, 2009, 06:46:08 AM: Can't really help you with the C11G BOB, but I use Peter Hommans Digispeed board for lathe spindle control and it works very well controlling my VFD.

Peter
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Grand Master B on December 01, 2009, 07:17:27 AM: Yeah its pretty simple setup,

1. The C11 F to V should only consume less than 10 mA.
2. The 10V input will be fine provided that in the VFD (pretty sure it will) has a selection for maximum input voltage. So its just a matter of setting up the BOB at its maximum frequency and adjusting the pot to output maximum voltage. will be like 9.3v for example (less than 10 as the maximum you have is 10). So then in the VFD the maximum input will have to be set to that value.

In the manual for the VFD there should be a part with input voltage vs speed that's the menu selection you are looking to set.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: PROTOPLANT on December 01, 2009, 04:40:19 PM: Hmm, Having trouble with this. I just hooked up the 10V to the C11G because I measured the draw at @ 14mA so figured it would not hurt anything. It sort-of works, but it takes a long time for the speed to stabilize, and it seems to be super non-linear. Also, it seems to have different speeds depending on if you are increasing S or decreasing it. IN other words if you type in 50, then 100, then 150, etc you get different results than if you go backward from say 500 to 450, to 400 etc.

I have it set so that 8V is the maximum and this does not seem to saturate the F-V converter.

Suggestions?

Thanks,
Dustin
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Grand Master B on December 01, 2009, 07:14:58 PM: There are two things you can look at.

1. In mach under Motor tuning=>spindle your acceleration may be too low.

2. In the VFD there is a setting for acceleration/decelration if this is too low it wil be slow to respond also.

3. Also if 8v is the maximum output for a specific RPM then the VFD frequency will have to be set for it to spin at that RPM.

just go over
-mininum input voltage setting
-maximum input voltage setting
-acceleration
-decelration
-frequency at max/min RPM

take a little bit of going thru the menus to get it all set correct.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: HimyKabibble on December 01, 2009, 07:56:55 PM: Quote from: PROTOPLANT on December 01, 2009, 04:40:19 PM
Hmm, Having trouble with this. I just hooked up the 10V to the C11G because I measured the draw at @ 14mA so figured it would not hurt anything. It sort-of works, but it takes a long time for the speed to stabilize, and it seems to be super non-linear. Also, it seems to have different speeds depending on if you are increasing S or decreasing it. IN other words if you type in 50, then 100, then 150, etc you get different results than if you go backward from say 500 to 450, to 400 etc.

I have it set so that 8V is the maximum and this does not seem to saturate the F-V converter.

Suggestions?

Thanks,
Dustin

I had a C11 that I used for spindle control for a while. I also had a difficult time getting it to work as I wanted. I never did figure out any kind of system to get it setup properly, but I did eventually get it working reasonably well. It was a combination of settings of step pulsewidth and steps/unit. Unfrotunately, I don't remember what the settings were.

Regards,
Ray L.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Grand Master B on December 01, 2009, 09:07:06 PM: The hardest part is getting the numbers to match up having 500 RPM = 500 RPM and staying linear over the entire range, Takes some calculating and tweaking no real way around it.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Matospeter on December 01, 2009, 09:11:02 PM: I have the C11g On my recently converted Lathemaster RF45 style machine. I have a belt drive conversion I made for it and run the machine with a teco sensorless vector drive off the C11g board. THis is my first cnc machine and I built it myself with considerable help from people on the cnc zone and from a pair of very nice fellows off line. I have to say that I am very glad I went with the Cnc4pc board. It has made getting all these items working real easy. I have had no problems with the board and I am quite sure I had at least a few times wired things improperly before I got it working right and nothing went up in smoke other than a Gecko servo drive I really goofed on. My three phase motor is setup with a belt drive as I said and I am really enjoying the near six grand spindle speed. I have a two tier pulley setup and did my best to configure it in Mach3. It has been working very well for a couple weeks now and many hours of actual spindle time. So far the only issue I have found is that sometimes under a longish rapid movement for some odd reason the spindle seems to slow down a little and then once the rapid is done it goes right back to where it was. I bought myself a laser tachometer to check and verify my spindle speed settings and I am seeing speed accuracy of around plus or minus 20-30rpm. The higher the speed the more error but to be honest I have not spent a lot of time fine tuning the steps/inch or velocity settings in config for the spindle. It did take some time to find a sorta sweet spot that allowed me to show the max rpm at max selected spindle speed whilst still having the lower speeds to be close to actual. I think that there are actually two ways to wire it up but I do not remember how just now.

Arturo tried to help me with this issue but I actually got some outside help before he got to me which was in the same evening. No fault of his just bad timing on my part. I gotta say that having infinite spindle speed control and on off in the software is a must have feature. I am now trying to figure out the simplest way to hook up some kind of relay for my flood coolant system off the c11g. Only thing I wish is that these boards( all BOB's really) had more inputs but I understand that is a feature of the parallel port mostly. Again, true novice here talking so be gentle... peace

Pete
865-363-9218
Matospeter@charter.net
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Grand Master B on December 01, 2009, 09:43:51 PM: Sounds good, it takes quite a bit fooling to get the two matched up, the higher the speed then the less resolution you will have, I have it setup form 0-18000 RPM so the higher speeds are less accurate but within 100 so no big deal, unless you are using the two relays on the board then one of them will be fine for running the coolant pump pins 1 and 16 I beleive control those.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Matospeter on December 01, 2009, 10:20:52 PM: That is what I figured, but what kinda relay and electronics/ wiring do most of you guys use for this? thanks and peace...

Pete
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: PROTOPLANT on December 01, 2009, 11:51:43 PM: Thanks all for the help, it looks like I am going to need to mess with it a significant amount of time to get things up and running, that is the way these home-made machines go :-)

Pete, are you referring to the coolant pump wiring? If so one of the relays on the C11G should do the trick per GrandMasterB, but note the rated contact current and voltage. Is your coolant pump AC? If so and you are using the relays for something else you can get solid state relays for switching AC loads that are reasonably cheap, and the input will operate off of the 5V from the bob and you can switch 110-240VAC depending on what relay you get.

Hope that helps,
Dustin
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: M250cnc on December 02, 2009, 03:41:06 AM: Hi i also use the C11g and am very happy with it.

One thing not mentioned so far is pulleys, yes pulleys

Unless you set at least one pulley and them use that pulley Mach will not be able to correctly work out the necessary figure to control speed

Having set the pulley up you then feed the C11g with 12v

Next adjust the setting to give 10v at max speed of the PULLEY

Then drop the speed by 50% the voltage should drop to 5v

Only when you have achieved this do you connect to the VFD

On my lathe which i am using a SS i had a devil of a time getting 10v i had to adjust the pulse width to do it to 8.5 if i remember correctly

I converted a redundant PC power supply to supply the required 5 & 12 volt for my control systems as they are very stable and easy to come by

If you do a google search for " CONVERT A PC POWER SUPPLY TO BENCH POWER SUPPLY" you should be able to find the article

HTH
Phil
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: PROTOPLANT on December 02, 2009, 11:58:56 PM: Thanks for the comments all, I think it will work now after tons of messing around. The problem was something with the VFD power supply not cooperating with the C11G, or just not working properly. I tuned the output to be very linear with the 10V from the power supply, with in a few tens of mV, stable and nice. But with the spindle on the voltage was all out of whack, generally ~1V higher than with the spindle on, but with varying wildly +/- 1V or so of where it was with the spindle off. Both tests were done with the VFD powered on but just with it in the off state for one. The funny thing was that the 10V was stable, at least with a digital volt meter. I was afraid to hook the scope up to it to see if it was rippling but it looked solid because I don;t have a differential probe and am not sure what those lines are relative to earth.

I even measured the pulse widths and plotted the frequency output VS speed and everything looked fine. Finally I just hooked up a 12 supply and all seems to be working now, although I have not thoroughly tested it yet, tomorrow...

Dustin
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: ftec on January 02, 2010, 03:01:37 PM: I'm using CNC4PC C11 rev. 9.3 and I just can't get it deliver more than 9.3V from the 0-10V analog output. I get the 9.3V at S20500 while the max is S24000. If I go over 20500 rpm the voltage will drop again to somewhere around 8.5V. My VFD does not deliver 12V so I'm using an external DC/DC converter which delivers 11.88V from the 5V supply, a 0.1% error I guess shouldn't make that much difference, or? Any ideas what to try next. (Unless - being sarcastic - the card rev # 9.3 means that you need to stick with 9.3) :) :(

/Risto
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: HimyKabibble on January 02, 2010, 06:16:48 PM: Quote from: ftec on January 02, 2010, 03:01:37 PM
I'm using CNC4PC C11 rev. 9.3 and I just can't get it deliver more than 9.3V from the 0-10V analog output. I get the 9.3V at S20500 while the max is S24000. If I go over 20500 rpm the voltage will drop again to somewhere around 8.5V. My VFD does not deliver 12V so I'm using an external DC/DC converter which delivers 11.88V from the 5V supply, a 0.1% error I guess shouldn't make that much difference, or? Any ideas what to try next. (Unless - being sarcastic - the card rev # 9.3 means that you need to stick with 9.3) :) :(

/Risto

What voltage are you providing to it? The spindle control will NOT be able to provide the full input voltage. So, if you want 10V out, you'll have to provide it with 11-12V in.

Regards,
Ray L.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: ftec on January 02, 2010, 06:22:18 PM: Quote from: HimyKabibble on January 02, 2010, 06:16:48 PM

What voltage are you providing to it? The spindle control will NOT be able to provide the full input voltage. So, if you want 10V out, you'll have to provide it with 11-12V in.

Regards,
Ray L.

11.88V as I said in the post. I'm now using an adjustable Mascot to get little over 12V and this seems to have some effect but it doesn't convince yet ... (edited).
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: PROTOPLANT on January 03, 2010, 01:54:56 PM: ftec,

It sounds like maybe it is a setting in the spindle setup in mach 3 under the motor tuning tab. I had to mess with the pulse width and rate etc to get what I wanted out of the thing. It took quite a bit of messing around, but now it works well, my only complaint is that the speed takes a few seconds to stabilize, but it really does not matter, I am super happy with how it works now.

Dustin
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: PROTOPLANT on January 03, 2010, 02:04:27 PM: One other thing I cannot figure out is the pulse width setting, can you not change the value independently? I had to set it to 10us on the spindle to get the voltage high enough, but I would like to have the servo pulses be 5us. Is there any way to do that? Now it just changes all the values at the same time.

Dustin
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: ftec on January 03, 2010, 04:01:38 PM: It seems that I got the spindle analog voltage issue solved for the C11 card for my 24000 rpm spindle. I believe all the cnc4pc cards use the same concept for the voltage, C11G as well.

The answer for the linearity issue can be solved from the pulley setup. In my first attempt I set the pulley max rpm to my spindle max rpm 24000. This resulted a voltage of 9.3V @ S24000 and 7.5V a@ S12000. You can get better linearity between S0 and Smax by adjusting the pulley max rpm over the true Smax rpm.

After many attempts I now have pulley max set to 27500 (ratio =1) and using the pot on the C11 card the voltage is adjusted to 10V@S24000 (i.e. my spindle max rpm). This resulted 5.04V@S12000 which certainly is pretty good and enough for my purposes. In the motor tuning I have (mm based) steps per unit 1000, Vel 2700, acc 500, step pulse width 2us dir pulse width 2us (btw. if you noticed, these pulse width values are shared with the servo axis why I have left those to be what I had them tuned for the servos.)

A very small capacitor across the analog GND and voltage could stabilize the analog control signal from drifting but I haven't tested that yet. A cheap way to shield the analog signal is to use a cable taken from say a RS232 D9 sub cable which usually are shielded cables. Only the other end of the shield should to be grounded to signal ground (otherwise currents can flow thru the shielding).

Regards,

/risto
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Peter Homann on January 04, 2010, 09:23:13 PM: Quote from: PROTOPLANT on January 03, 2010, 02:04:27 PM
One other thing I cannot figure out is the pulse width setting, can you not change the value independently? I had to set it to 10us on the spindle to get the voltage high enough, but I would like to have the servo pulses be 5us. Is there any way to do that? Now it just changes all the values at the same time.

Dustin

The problem you have is that, the speed controller chip converts the pulses from the step pulse to an analog voltage via a charge pump. With a longer step pulse, more energy is put into the chargepump and a higher voltage results.

On by Step/Dir DigiSpeed, I have additional circuitry that ensures that the pulse length fed to the chargepump, is allways the same regardless of the Mach3 step pulse width. That way, you can set the step pulse width to match what your motor drives need rather that what the analog output voltage signal needs.

http://homanndesigns.com/store/index.php?main_page=product_info&cPath=1&products_id=39

Cheers,

Peter.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: HimyKabibble on January 04, 2010, 11:22:32 PM: Personally, I'd take a PWM spindle control interface over a Step/Dir charge pump any day. Peter Homanns DC03 works flawlessly, and is VERY accurate and linear. I can typically set VFD frequency to with 0.5Hz or better.

Regards,
Ray L.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Peter Homann on January 05, 2010, 01:55:49 AM: Quote from: HimyKabibble on January 04, 2010, 11:22:32 PM
Personally, I'd take a PWM spindle control interface over a Step/Dir charge pump any day. Peter Homanns DC03 works flawlessly, and is VERY accurate and linear. I can typically set VFD frequency to with 0.5Hz or better.

Regards,
Ray L.

Me too. :)
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: ftec on January 05, 2010, 02:28:01 AM: Quote from: Peter Homann on January 05, 2010, 01:55:49 AM
Quote from: HimyKabibble on January 04, 2010, 11:22:32 PM
Personally, I'd take a PWM spindle control interface over a Step/Dir charge pump any day. Peter Homanns DC03 works flawlessly, and is VERY accurate and linear. I can typically set VFD frequency to with 0.5Hz or better.

Regards,
Ray L.

Me too. :)

Very tempting, but I'd rather have used serial communications for the VFD if it only were possible with this Chinese thingie. With other benefits it would free the pin 14 for the 5th servo axis when using C11 card.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: Peter Homann on January 05, 2010, 07:12:27 AM: Hi,

Yes, I know what you mean. It wouldn't be too hard to do a Modbus to the Chinese VFD converter. Just not enough time to do everything.

Cheers,

Peter.
Title: "Error" in C11 manual - pin14 frequency
Post by: ftec on January 06, 2010, 06:48:49 AM: Regarding my reply #18 there is a little more to it.

The C11 manual says that you need to set the Velocity to max in the Motor tuning /Spindle. Then it also says (which first slipped my attention) that the C11 card requires a 25kHz pulse train in pin 14. This means that setting the spindle speed to max applies only when using the 25kHz Kernel speed. With higher Kernel speeds the spindle speed should be set so that Steps * Vel / 60s = 25kHz. The linarity changes if the frequency is changed to what the manual says. I decided to keep the Vel in max though I use a Kernel speed of 45kHz.
Title: Re: CNC4PC C11G Analog Output Spindle Control
Post by: JHChoppers on January 06, 2010, 05:21:32 PM: Quote from: PROTOPLANT on December 01, 2009, 01:02:51 AM
1- The VFD I am using ( a 15HP GS3 from automation direct) has an analog output supply of 10V at 20mA max. The C11G has a required input of 12V @50mA. Do I really need another isolated power supply? I feel like I have about enough in that control panel... 24VDC, 24VAC, 12VDC for the drives, 60VDC for the servos, and on and on.....

Doesn't the GS3 have RS485 ModBus? Try controlling the RPMs/Hzs via Modbus. You should be able to the achieve the target RPMs with no problems...

We use ModBus to control our 10HP Spindle
http://www.youtube.com/v/QUB8hFWrnfw&hl=en&fs=1&rel=0&color1=0x006699&color2=0x54abd6&border=1

JH