Lab-Volt mill conversion - (attn Marty)

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Rex
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Lab-Volt mill conversion - (attn Marty)

Post by Rex »

Marty, I read with interest your notes and photos on converting your Lab-Volt lathe. Thank you for sharing that.

I am about to start on a Lab-Volt mill with identical controls, except for the extra axis. I have on hand a CNC4PC C11 board which I will probably use. Before I start, some basic questions:

The transformer takes mains power and sends it to a small board with a big capacitor, with a bridge rectifier in the circuit. This would appear to be all that's needed for a power supply.

What is the power unit at the top of the cabinet?

It has a spindle controller board at the bottom of the cabinet. Why did you also need the C6 board?

Can you tell me what the stepper wire color codes are - which is power, ground, direction, step?

Did you happen to produce a schematic of your finished product, or some sort of wiring diagram?

Any help appreciated, including tips from anyone else who has been down this road.

Rex B
Fort Worth TX
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Last edited by Rex on Thu Aug 21, 2014 9:55 am, edited 1 time in total.
Marty_Escarcega
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Marty_Escarcega »

Rex, let me review my pics. I did not do a schematic....I don't think I will look. Can you move the machine with the original controller manually?
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Marty_Escarcega »

Rex wrote:Marty, I read with interest your notes and photos on converting your Lab-Volt lathe. Thank you for sharing that.

I am about to start on a Lab-Volt mill with identical controls, except for the extra axis. I have on hand a CNC4PC C11 board which I will probably use. Before I start, some basic questions:

The transformer takes mains power and sends it to a small board with a big capacitor, with a bridge rectifier in the circuit. This would appear to be all that's needed for a power supply.
The toroidal power supply is power for the stepper motors fed by the stepper drivers, and I think it provided 12v for the spindle drive. I may have used 12v to power the CNC4PC boards, measure the outputs....yes reuse it.

What is the power unit at the top of the cabinet?
If memory serves, it is a power supply for the stepper control logic. I think it was a 5v power supply. Power it up and measure it. Follow the wires down to the stepper drivers and measure there. Closely look at my pictures by enlarging them. You will see that a pair of leads are capped off. Its been so long since I did the conversion I cant remember and I don't have schematics. The machine has long been sold

It has a spindle controller board at the bottom of the cabinet. Why did you also need the C6 board?
To control the linear voltage required by the spindle control board. Read up on the C6 board. Docs are on CNC4PC's website. Also, find the docs for the spindle control board. I think its a Minarik?

Can you tell me what the stepper wire color codes are - which is power, ground, direction, step?
Do a little sleuthing from my pictures, enlarge it. You will see what I think is the C10 breakout board, note the wire colors for the X and Z axis and then go down to the stepper drivers and match them up. If you have a working original control, you can put your meter on these input pins. When you move the axis in one direction, dir will alternate between hi and low on your meter

Did you happen to produce a schematic of your finished product, or some sort of wiring diagram?
I looked, and didn't keep them. There is an outside chance I can reach the fellow I sold it to

That conversion was fun and easy for me. It turned out quite well as I was able to reuse much of the control. Please take pics and keep us posted of your progress. Ask questions along he way. I will try and answer them

Here is a link to the pictures on my google photo album Rex is referring to:
http://tinyurl.com/Labvolt-CNC-Lathe

Rex, I would also be willing to talk to you on the phone. PM me and I will send you my number. Together we can sort it out. All I ask is that you share your schematic with the next guy.

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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

Marty
I was able to move the axes when I first got it, but now it errors out at power-on. But I think I can get past that and check the voltages.

I did read up on the C6, and found my C11 board includes spindle control, so the one board should be all I need.

My goal for today is to trace down the existing wiring and sketch out what goes where.

I'll PM you my number. Yes, I'll document the process.

Thanks

Rex
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

So the toroidal ps supplies 12V for stepper movement and spindle, and the small ps is 5V for logic?
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Marty_Escarcega »

Rex wrote:So the toroidal ps supplies 12V for stepper movement and spindle, and the small ps is 5V for logic?
Double check but yes, small power supply is 5VDC. Toroidal has 2 power supplies if memory serves. 12V for DC spindle control and it might be 48VDC for the stepper drivers/stepper motors.

Yes, today sort out your voltages. Document them. Download the docs for the C10 breakout board from CNC4PC so you can refer to it when looking at my pictures. Find the X and Z axis step/dir on the breakout board and then note the color wires I used for step and direction (orange and white). Using my pic, note the wires on the lower left corner of the stepper driver board and which pin they are connected to. I believe the other two wires on that connector go up to the 5VDC power supply. Verify all. That should get you where you can document everything. I tried to reuse as much of the existing wires as they all reached and had the connectors on them. C11 appears to be a good choice.

Hope this get's you going in the right direction. I will PM my phone number to you in case you have questions. Please do take pics and post your progress here.

Marty
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

OK, I spent the day chasing down every wire and checking voltages.
I have 8 pages of sketches and notes.

The motor power board is a KB Electronics model KBLC-240DS
Of course, that is the ONLY manual PDF on the KB site which is not linked to download.
I think this will be relatively easy to interface with my C11 BOB, which has C6 spindle control on the board.

Stepper driver boards - I tried to measure the voltages at the wiring between BOB and driver board, but could not get repeatable readings. It may be because I did not know what I was looking for (voltage range, AC or DC) so may have had my meter on the wrong range? At any rate, at some point the manual control quit moving the steppers, although the DRO continued to show movement. Hopefully nothing is damaged on the driver boards.

Marty, I downloaded your conversion photos, but was unable to get decent resolution. Nevermind, I fixed that.
Any way, looking at your photos, it appears the Orange input wire is Step, and the white input wire is Direction. These correspond to my Gray and Yellow wires, respectively. These lead from your C10 board 2 & 3, and 4 & 5. If correct,that is the primary piece of info I was in need of.
Q: How do you know which BOB terminals are for which axis? Is that configured in your CAM program? I see now that the BOB is marked X step, X Dir etc.

Power Supplies - The unit at the top of the cabinet is indeed 5V. It powers the breakout board.
The toroidal PS has several outputs.
The largest leads feed 90V to the bridge rectifier, which passes 90V DC to the capacitor board.
The smaller leads feed 74V AC to the board in 2 places.
Output voltages from the PCB are:
72VDC to the BOB
72VDC to the BOB then to the motor controller
I'm still scratching my head over that one. Seems like a lot of power for a PCB
90VDC goes to the chopper/driver boards. Each is fused at the board. those little stepper motors need that much power?

I think I'm at the point of removing the OE BOB and mounting the C11 BOB, then wiring it per the documentation with your photos as the guide. It will probably be Monday before I get back at it.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Marty_Escarcega »

Rex wrote:OK, I spent the day chasing down every wire and checking voltages.
I have 8 pages of sketches and notes.

The motor power board is a KB Electronics model KBLC-240DS
Of course, that is the ONLY manual PDF on the KB site which is not linked to download.
Says to use the KBIC manual on this page: http://www.kbelectronics.com/kb_manuals.html

I think this will be relatively easy to interface with my C11 BOB, which has C6 spindle control on the board.

Stepper driver boards - I tried to measure the voltages at the wiring between BOB and driver board, but could not get repeatable readings. It may be because I did not know what I was looking for (voltage range, AC or DC) so may have had my meter on the wrong range? At any rate, at some point the manual control quit moving the steppers, although the DRO continued to show movement. Hopefully nothing is damaged on the driver boards.
The DIR line should go 0 and 5VDC the other one will be step. You just needed to measure it at the stepper driver board I believe


Marty, I downloaded your conversion photos, but was unable to get decent resolution. Nevermind, I fixed that.
Any way, looking at your photos, it appears the Orange input wire is Step, and the white input wire is Direction. These correspond to my Gray and Yellow wires, respectively. These lead from your C10 board 2 & 3, and 4 & 5. If correct,that is the primary piece of info I was in need of.
Q: How do you know which BOB terminals are for which axis? Is that configured in your CAM program? I see now that the BOB is marked X step, X Dir etc.
Not CAM. You configure this in the control software. Mach3 in my case, you could also use EMC which is based on Linux, though I am not familiar with it.

Power Supplies - The unit at the top of the cabinet is indeed 5V. It powers the breakout board.
The toroidal PS has several outputs.
The largest leads feed 90V to the bridge rectifier, which passes 90V DC to the capacitor board.
The smaller leads feed 74V AC to the board in 2 places.
Output voltages from the PCB are:
72VDC to the BOB
72VDC to the BOB then to the motor controller
I'm still scratching my head over that one. Seems like a lot of power for a PCB
90VDC goes to the chopper/driver boards. Each is fused at the board. those little stepper motors need that much power?
Sounds very unusual on the power supply voltages. I would expect it would be the same as my lathe was. Coming STRAIGHT off the toroidal supply is AC, to the bridge rectifier. The opposite terminals would be measured DC

I think I'm at the point of removing the OE BOB and mounting the C11 BOB, then wiring it per the documentation with your photos as the guide. It will probably be Monday before I get back at it.
That machine was self contained. The computer is a PC104 if memory serves. But yes it and the board its on goes. Mount your C11 and start wiring it up.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

I have both Mach3 and LinuxCNC. At first glance MAch3 sure looks more user-friendly

I agree on the voltages. I sure wasn't expecting anything that high.
The motor power went through the bridge rectifier, but the other taps, with smaller gauge wire at 70+ VAC, were rectified on the board mounted to the cap. I should pull that board and look at the underside.
At any rate, both of the 72VDC outputs go to the old BOB, and I won't be needing that on the C11. However, by the documentation on the C11 it looks like I may need 12VDC, and possibly 5VDC from a separate PS or the PC. If so I may just use a couple of wall-warts on a short power strip.
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Marty_Escarcega »

Rex wrote:I have both Mach3 and LinuxCNC. At first glance MAch3 sure looks more user-friendly

I agree on the voltages. I sure wasn't expecting anything that high.
The motor power went through the bridge rectifier, but the other taps, with smaller gauge wire at 70+ VAC, were rectified on the board mounted to the cap. I should pull that board and look at the underside.
At any rate, both of the 72VDC outputs go to the old BOB, and I won't be needing that on the C11. However, by the documentation on the C11 it looks like I may need 12VDC, and possibly 5VDC from a separate PS or the PC. If so I may just use a couple of wall-warts on a short power strip.

You should be able to use the 5VDC power supply in the machine. I can not recall if one of your supplies is 12VDC
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Re: Lab-Volt mill conversion - (attn Marty)

Post by Rex »

I will use the existing 5V PS, but the C11 card specifies a separate source for the motor control section to preserve the opto-isolation. They suggest a USB cable (included with the card) from the PC or a wal-wart.
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Re: Lab-Volt mill conversion - (attn Marty)

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Rex wrote:The motor power board is a KB Electronics model KBLC-240DS
I think this will be relatively easy to interface with my C11 BOB, which has C6 spindle control on the board.
Be vewy, vewy careful with the C-11/KB motor control hookup. I have a C-11 with KBCC-125R (R = reversing) on my lathe and vaporised a circuit track on the C-11 due to my ignorance about isolation and Arturo's documentation in the C-11 being vague (to me). I ended up installing a KBSI-240D Signal Isolator to fix the problem. Fortunately nothing else was damaged on the C-11 and I was able to fix the damaged circuit. It's working fine now & I have good speed & direction control from Mach.

ps: I was able to get 2 used KBSI-240D's on ebay for $30.00 each. For that price I figured why not get a spare.
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