Retrofitting a 1986 Maho MH400E

Oh, reversed axis encoders cables will of course cause run away. It senses an error in Y, powers motion in X which moves, now it commands motions in X to correct that error, and Y accelerates...... both run away.

You just unplug the M23 connectors of the encoder cables and interchange them
Mark

Changed the signs and the machine latches on! The axes have to be switched of course. It keeps going back and forward like on the Philips, but noticeably faster. I guess that means I should get to tuning until it sounds like before?

EDIT: The movement is within 1 micron on the DRO by the way, it just maintains position that way.

EDIT2: okay, the behaviour is definitely wonky and needs to be fixed, but I'm really stoked I managed to get this far! It's time for lunch.

EDIT3: before I go, just in case: Z DRO doesn't register movement at all while the axis moves (but the encoder worked when break released and drive wasn't energized), the rest I have to assign correctly and check with a dial indicator whether the commanded increments check out.

Cool. Another milestone. Mine also has some audible pulsing. I should take another go at fine tuning.

My current situation is that it's enough for me to get the drives working properly (with limit switches and encoders) and I can get back to work, since I've been using an external VFD to drive my bolt on high speed spindle back on the Philips. The gearbox and main spindle hold a promise of further problems, since compiling files is completely new to me (all of this is completely new to me, as you've seen from my idiotic musings and the dumb problems I generate, describe then solve).

Any ideas why the Z axis DRO doesn't change position now when the axis is moved, but it did when drives didn't energize and the brake was released? This tells me the encoder is wired to work somehow, but it ceases to function once it's inside the feedback loop for some reason.

A big Thank You to all that are contributing to this retrofit thread. This is really useful information for MAHO machines and also others.
It is also proving out Marks retrofit documentation and also some of the variables that come up

---

which I think is extremely useful information.
Glemigobles was wondering what model/series of indramat servo drive your machine has?

Bob

J Green,

My machine has the same 3TRM2 servo drive as Mark's. The BOM in the schematics from DMG list it's full name as 3TRM2-G11-W0/ZE5, and while it's physically just one board (usually now they're separate modules for each motor), it does have two modules listed for the X-Z and Y axes. So I guess they're subcomponents.

The motors are Indramat MDC 10.20F/MMA-0/S06 (two of) and one MDC 10.40C/MMA-1/S06. Can't tell you all the info on the motors since the plates are located in very inaccessible positions. I know they're 2000 RPM max and the axes torque are listed in the machine instruction manual (2x3,7 Nm and 1x8 Nm for the Z axis).

I can't stress enough how helpful Mark's been all this time, as well as other posters like PCW. I literally have no technical education to speak of (I studied literature at university) and I managed to get this far with help from the forum (and all the manuals of course, especially Mark's wiring diagrams).