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You guys did such a wonderful job with my spindle inverter i wanted to make sure i get my MPG wired correctly. Here is what i got and i will be wiring to the MPU11. Thanks MPG wiring diagram

RPMAN,

Unfortunately I can't be quite as helpfull with your mpg but hopefully the information I provide will get you pointed in the right direction.

A couple of notes and comments:

1. Our MPG header on the MPU11 supplies 5 VDC while your mpg appears to require 24VDC. You may be able to provide an external supply but that leads me to point 2.

2. Our axis select and multiplier select require that they be connected to the 5V COM on the MPU11 mpg header in order to be seen as a logic "1". If your mpg uses simple contact closures for these circuits you should be ok (based on the drawing, it appears that they are contact closures). If your mpg does not use a simple contact closure for these outputs than it is likely that you won't be able to use you mpg and that if you do connect it, you may damage the MPU11.

3. The encoder appears to be compatible. All you can do is try it and see if it counts but as long as it's 5V it shouldn't hurt anything.

MPU11 mpg pinout:

Pay carefull attention to the header orientation on this drawing - notice the two keys along the right side of the header for reference

Download the fullsize pdf here:

I think the 24vdc is a typo because I have another drawing for connecting through modbus that shows everything is 5vdc. I will try and post it just so you can take a peek at it. Thanks

Here is the link that has the other wiring information for the mpg2. I belive that this information has typo's also. For one, line 13 should read "orange" and line 14 should read "orange/black". I pretty much have it figurred out. The mpg acording to this chart has 3 required 5vdc inputs (encoder,switch com, and led). Where the mpu11 has an output for 1 5vdc or "red" I combined the 5vdc input for the encoder and the switch com for the mpg2. The mpu11 has a pin for the led light so I connected the mpg2 to that pin.
http://cnc4pc.com/Tech_Docs/guide_for_M ... Modbus.htm

ewest posted this on cnczone about his experience with connecting a CNC4pc MPG to his mpu11

ewest writes... You can absolutely use a different MPG with Ajax, just as long as the encoder puts out DIFFERENTIAL output - that is there's a +5, Gnd, A-, A+, B- and B+ lead. Differential means that instead of +5 and 0V between A or B and GND, the A+/A-, (and B+/B- leads too) swap polarity in respect to one another to indicate 0 and 1, as opposed to a single line going high or low with respect to GND. This scheme is implemented to reduce electrical noise, and you want to use this wherever possible. Electrical noise = missed steps or dropped encoder pulses = trash parts = wasted money. You can use a chip called a "DS26LS31CM" made by national semiconductor to change TTL encoders to differential output. Needs no external components. They're around a buck. Mount it as close as possible - preferably ON the encoder. Look here. I used a "CNC4PC.COM" MPG unit with my Ajax MPU11. Works fine. I think the chips come in non surface mount, but I like not drilling holes so that's what I used. Make sure your connections are solid. The CNC4PC MPG had single ended TTL outputs, so I had to make the board. It lives in the MPG itself, soldered in place. I used two spare lines in the cable to run the A- and B- wires.

http://cnczone.com/forums/showthread.ph ... post739142

Thanks for the input. The mpg2 does not come with differental output so I had to buy a mpg wheel that fits into the mpg2 that is differental output. The wiring harness has extra wires run threw it incase you upgrade the mpg2. The e-stop switch has 4 contacts but they only connect 2. I thought about using a couple of the extra wires in the harness to use the two other contacts required for the mpu11 wiring for the e-stop switch but the one thing that I am not sure of is the amp rating of the switch is .5 and I am not sure if the 24v transformer and e-stop contactor will exceed this .5 amps. Not sure on that one. So, I was going to just get a beefier 4 pole e-stop switch. I would love to use the one on the mpg2 but I am just not sure.??? Thanks again for the input

Is there any way to troublseshoot whether the MPU11 is recieving pulses from the MPG?

The aixs and multipliers selectors are working properly, but I have been unable to move an axis with the MPG.

Thanks,
Will

Are you using the mpg2 or a different mpg? If you are using the mpg2, did you do the modifications that are listed above about the changing the mpg2 wheel to a line driver output? Also if you want to know how to use the e-stop button on the mpg2 with the mpu11 use the link above to see the cnc zone thread about the mpg2 and ajax controls.

I think my problem may have been an issue with an old version of the Ajax plugin. I just updated to v1.10, and it is now working.

-Will

Good to hear you got it working Will. Did you use ajax brains for the "mpg2"? I am still waiting for my dirrerential output driver chip from digikey.