Need Help!- Retrofitting my maho mh400c

[pirke86]

Hello everybody,

I would like to retrofit my Maho mh400c with emc2.
This is because the old philips 432 control is broken and it's getting harder and harder to find the right parts for it.

I would like to use the original indramat 3trm2 servo drive and the linear encoders.

I found the following thing: http://www.cnczone.com/forums/showthread.php?t=74532/
It takes the step/dir signal and makes it into an +10v/-10v signal.

Perhaps its usefull?

Any info that can be usefull for my build would be highly appreciated.

[kudos]

hi

a macho has recently been done, check out the linuxcnc.org forum for more info on it

or click here
http://www.linuxcnc.org/component/op.../lang,english/
its a bit bigger machine

im sure the person who did this one will give some insight into what he has done etc.

rob

[jmelson]

Originally Posted by pirke86 Hello everybody, I would like to retrofit my Maho mh400c with emc2. This is because the old philips 432 control is broken and it's getting harder and harder to find the right parts for it. I would like to use the original indramat 3trm2 servo drive and the linear encoders.

What you suggest can work, but it is a poor approach. A major problem is the rate at which software can spit out step pulses is often too low, and severely limits the machine speed.

There are a number of advantages to getting rid of the steps entirely. There are several interfaces available for EMC that generate analog velocity commands to existing servo amps. These also have encoder counters and digital I/O for spindle control, coolant, etc. Mesa makes a couple lines of these, Pico Systems (my company) makes a flexible board "set" so you can plug in only the functions you need. See
http://pico-systems.com/oscrc4/catal...ex.php?cPath=8
While this package may at first seem more expensive than Mesa's, it includes everything you need, so no cables, break-out boards, adapters, etc. are needed to complete the system.

Jon

[pirke86]

jmelson,

This would be the perfect solution!
Can i use all the original component if i use your components?
Indramat,Tachos and encoders?
And what do i need for 3 axis.

[pirke86]

Could you make a list of all the parts i would need for the complete retrofit?

[jmelson]

Originally Posted by pirke86 jmelson, This would be the perfect solution! Can i use all the original component if i use your components? Indramat,Tachos and encoders? And what do i need for 3 axis.

If the Indramats are classic velocity servo amps, then you should be able to use all these.
The Tachs would feed back only to the servo amps, no rewiring or changing of servo amp tuning required.

The Pico Systems PPMC board set handles up to 4 axes. The left over channels can be used for other things like jog dials or spindle encoder. The basic PPMC set runs $780, or $855 with power supply and IEEE-1284 cable to the PC.

Jon

[pirke86]

i'm still looking at the mesa boards, they are a lot cheaper...
but i still dont know how it all works together...

[jmelson]

Originally Posted by pirke86 i'm still looking at the mesa boards, they are a lot cheaper... but i still dont know how it all works together...

The price difference is less than you think, as the Mesa requires a lot of adapters, breakout boards, cables, Opto-22 mounting boards, etc.

The PPMC has everything included on the boards except the actual SSR modules, so you can choose AC, DC current and voltage for your needs.

Either way, the encoders feed position info into the encoder counter inputs, and the analog velocity command output goes to the servo amp's command inputs. The Mesa produces a PWM signal that then goes into a PWM to analog converter. With the PPMC, there is a separate 16-bit DAC for each axis that produces the +/- 10 V velocity command. The only non-standard stuff you need to deal with is the signal that enables the servo amp, and sensing a fault condition from the servo amp. Usually, this can be done with some opto-couplers.

With the PPMC, your home and limit switches connect to digital inputs on the DIO board, their assignment is made in EMC2's hal files to specific functions. Servo enable, spindle and coolant control, etc. are routed through the hal files to the DIO board's digital outputs, where solid state relays are turned on.

Does this clarify it some?

Jon

[pirke86]

I'm gonna go with the mesa boards.
Everybody is very positive about them.

But there's anothor problem, my linear scales dont put out a quadrature wave.
apparently they give a sine wave.
I've been told this could easily be fixed witch a custom circuit using a comparator, but i'm no electrical engineer...
I've found somebody who can build this for me but i wonder if there is a existing solutions for this.

so basically my shopping list is the following:

A computer (of course)
A 5i20 card
A 7i33 card
A 7i37 card
Maybe another 7i37 card?
Some AIO 50 pin cables
Something to fix the sine wave to quadrature

What did i forget?

[smoregrava]

I find this thread very interesting. Because I have a Maho mh500C with a old 432 control.

I also have a small info page about the machine
http://smoregrava.net/Maho/mahomh500.htm

And as I work with CNC machines and edgecam i find the memory of the machine a big dissadvantage. I would really love to do dripfeed and be able to run programs that is 50 Mb.

At my work we use Fagor controllers. But I have looked into using Mach3 software and run signals to the 3TRM2 drives.

I'm vondering how much work it would be to set up referance search and get everything up stable.

Keep up this project!

[Al_The_Man]

Originally Posted by pirke86 But there's anothor problem, my linear scales dont put out a quadrature wave. apparently they give a sine wave. I've been told this could easily be fixed witch a custom circuit using a comparator, but i'm no electrical engineer... I've found somebody who can build this for me but i wonder if there is a existing solutions for this.

If they are the same as Heidenhain, OR are Heidenhain linear scales, the signal can be of two configurations, either 11µa or 2v p/p.
The normally can be squared up first and then converted to differential driver 26LS31.
Al.

[pirke86]

i havent looked at the encoders but i think their philips glass scales...

Btw
I don't heve to change the tacho's right? they go straight to the indramat drive?