Retrofitting a 1986 Maho MH400E

I'm attempting to put all my MH-C 700 wiring schematics here. They are the result of several months of painstaking wire tracing. As they exceed the upload limit I'll have to do them in 2 submissions. As I mentioned they were done by sliding a loose cable tie from end to end on every wire in the machine. Lots of scraped knuckles, swearing and sweat etc. I had to cut loose all the existing cable ties first and pull the wiring out of cable trays. The bundles are quite convoluted and many the same color, so it's easy to lose which is which especially where the bundle goes through bulkheads. The cable tie idea cures that problem and even allows a rest now and again without losing you place
Although I've done a lot of plant commissioning in my time, my first glance at all this left me a bit overwhelmed.
I did have the schematics for a similar MH 400, so I had a general idea, but in many ways it was just as misleading as not having it, especially with my machine being refitted with an non standard controller. An all that shuffling between drawing sheets and in German with Google translate: a nightmare

I hope for many people this presentation will be helpful. The way the drawings are, you can see where you might put the Linux interface cards where my Izumi PLC is. Or you could rebuild an older Maho an see where you could put and equivalent PLC or see how the old system might be better rebuilt.
Each individual drawing has everything in one place, so you can print it out and sit beside the machine and go through each subsystem with just one printout.
Each cable is labeled with it's core number, where they are multi-cored (mostly).
Each wire has the terminal number at each end
Each contact has the name of what it does where appropriate and/or it's I/O number/name  etc.
The X1/ X2 terminals are usually found along the bottom of the cabinet: X1 on the left merging to X2 on the right
The X3 and X4 are the terminal strips along bottom and side of the 24 volt to 220 volt interface relay board. I think these might be called the 28A1 card on the Maho drawings. Mine are on the cabinet door and originally, for the Philips controller, there were 3 of then. Now only 2 any only partly complimented with relays. I've seen them placed elsewhere on other Mahos. On the schematic for these boards you will note that some of these relays have quite a lot of interlocking logic.That may not be suitable for the LinuxCNC implementation as you could do it just as well in the program logic.
Similarly you note on the motor contactors, there is wiring logic which wont allow the spindle motor to attempt operation in both directions at once etc.
Sorry they are just mud maps

David

Here are the last of the schematics for my MH-C 700 rebuild.
Good luck
David

Probably should have started a new topic, but i might be wrong.
In talks to do a Maho 600 retrofit, from pictures paint looks quite good, but it was used as a grave for other stuff, so ...

Thanks for replying.
Yes maybe Tommy. And probably not on LInuxCNC at all!
But I read a lot of comments here on similar rebuilds that talk about maybe resurrecting old non Linux controllers and the pros and cons.
I'm hoping to add stuff on the pitfalls with the common problems with this generation of Mahos that are the same for all of our rebuilds.
I see stuff on the servo loop closing and my schematic shows pretty much the one we will all have to use.
My PLC program for the gear change should help with the very long discussion on LinuxCNC logic for this and also what it needs to do mechanically.
The group of old Mahos being rebuilt is broader than I realized until I got into marks stuff.
It seems to have gone quiet lately without me knowing how many of them turned out.

Best Regards
David

For db1981 on page 127:
Here is a photo of my two 24VDC power supplies that go to the terminal strips X2-6/ X2-7 and X2-140/ X2-141.
As you can see in the photo they are a very basic 3 phase 6 diode rectifier bridges like you might find in the back plate of an old car alternator. They seem ancient in comparison to the DIN rail mounting ones these days.
I put my very crude Hantek 6022 USB oscilloscope on the X2-140/141 and you can see from the trace it has the high peaks of which you speak. I've also added a page out of the Heidenhain TNC 155 mounting instruction manual where you will see the exact same type of curve.They mention that the TNC has been designed for this type of power supply. From the oscilloscope you can see the time base is 3.33ms as you would expect from the 6 pulses per cycle at 50Hz. I'm not too confident of the voltage calibration, so I used my Fluke to test them. The X2-140/141 supply showed 25.7VDC RMS and the X2-6/7 showed 24.5VDC RMS. The machine was booted and homed so the 7K1 contactor is closed, or you wouldn't see voltages on those terminals. In that situation the X2-140/141 supply is loaded by the Heidehain and IZUMI PLC back planes so I think 24.5VDC RMS is okay. The X2-6/7 isn't much loaded in this situation so I'm going to leave it as is. It drives the gear change system.
The 6T1 transformer that supplies these 24VDC rectifiers incoming 415VAC is wired to the nominal primary winding which i would think is 380VAC, being German. But it also has +5% and -5% tappings if you want to fiddle with it. If you wire to the +5% tappings (3 off) the output voltage should drop accordingly.
Also, there is a 19T1 transformer that puts out 220VAC for the main supply to the Heidenhain controller, and in my case, also the Izumi PLC. I thought it wise to have both devices on the same supply connections. With LninuxCNC you might do the same. In this case the transformer primary tappings are labelled 400VAC, 420VAC and 440VAC.
Since the Heidenhain controller has it's own rotary switch that does a range of supply voltages one would wonder why the 19T1 transformer exists at all. I think it may be to isolate the machine from power surges from industrial settings or lightning strikes etc?

Good luck with it,
David

 

A quick addition to my previous posts. This is my Heidenhain HR250 remote handwheel. Ugly looking thing, but works nicely. Downside is you have to go back to the console to swap axes and change gear ratio etc. Upside is it can bounce of the floor without damage and it has magnetic feet shown. Having it held steady is helpful for precision inching.

David