[Davey Boy]

Thanks Uli12us. I will send you a number.

Something else I was considering... has anyone tried connecting their 3TRM2 to an external controller such as Mach or Linux and simply using open ended step and direction inputs to drive the machine?

I understand the importance of feedback to the controller, but at this point, I really don't know if my machine would work properly even with a new scale.

[Lohmeyer]

Maho's use AC Servo motors. You can't run them open loop. A rotary encoder or linear scale (or both) is required. Most Maho's I know of have both a linear glass scale on the axis and rotary encoder on the motor. This provides an even better feedback system than a glass scale alone, and allows the machine to sense impacts or problems. Like the motor spinning further or faster than the table movement, so it knows something smacked into something else, and it can shut down with an error code.

If you did convert your machine to Mach3, you could possibly use the rotary encoders. But, you can't get away with using Mach3 in it's basic state - using stepper motors and a parallel port - not without significant expense and throwing away all the "good" parts on the machine like the better AC motors, and Indramat drives. You would be better off using a software/controller package that supports the existing AC servo motors and Indramat controllers (which Mach can do with the right hardware, but I'm not sure with your existing drives and motors). I can get more into the technical details if you want.

My suggestion is to see if you can bypass the bad encoder, or trick the machine into thinking it's OK so you can verify the other parts of the machine before spending serious money. Doing a Mach3 (or any controller) retrofit is not trivial. It's only worth doing if you a) want to do it for fun and the learning experience, or b) really like the machine enough to make your time/money worth it. If (a) doesn't apply, usually (b) isn't worth it for such an old machine. You'd be much better off buying something else.

The glass scale is broken on one end, right? Can you move the axis to the other end of the scale and get it to work? At which end does the machine home? The broken end or good end? If the scale is good on one and, and the machine homes to that end, you can probably ignore this problem for now. I just reviewed your pictures, and it also looks like you are missing the bracket that holds the scale's head. So, looks like someone else started the repair, or tried to bypass it and didn't finish.

If it homes to the good end of the glass scale, get a new bracket, and get it working, and so you can verify other stuff first, like why the X axis is moving while the E-Stop is pressed. You can probably solve issues like that regardless of the broken Z axis glass scale. Because if anything, the broken scale would stop the machine, not let the it move.

Stages of "life". The machine should power up and pass self checks. It does that - stops at I01 error which is normal. Second step is to prevent the X axis from moving when it shouldn't (someone probably bypassed an important safety interlock!). 3rd step is to bring up the hydraulics (and have the I01 error go away). 4th step is to home the machine, which will probably fail due to broken Z axis scale. You are still at the 2nd step if I understand correctly. Glass scale isn't a factor yet. If you can get to the 3rd step, you can probably exercise the machine in diag mode (move the axis back and forth with the diagnostic switch on) and verify much of the machine without replacing the glass scale yet.

Regards,
Mike

[Davey Boy]

Thank you very much Mike for taking the time to so completely explain what I am dealing with here. It is encouraging to know that the people here are so helpful. It's too bad the guy I bought it from was and is anything but helpful.

I am familiar with Mach, as I use it to run a metal spinning machine I built. I agree that the Indramat controller and drives would be the best parts to keep.

The glass scale is broken near where the cover is peeled open and also near it's midpoint, so I don't know if homing will be possible. I'm not sure if the Z's home is extended (homing likely doable) or retracted (homing a problem). I'll see what the manual says and make a bracket for the reader.

Without a schematic, it's tough to figure out what's what with the wiring. The e-stop on the console has definitely been bypassed, for some reason, and that part of the circuit also powers the start button. I think I can put the e-stop back into the loop and perhaps that will make the reason it was bypassed more obvious.

As you noted, if I could just exercise the machine, I would feel much better about laying out more dough for a scale, as opposed to parting the thing out on Ebay. With trying to get a new business going, cash is a bit tight and I think my wife is about ready to part ME out on Ebay!

Thanks again,
Davey Boy.

[uli12us]

The old machines normally have a resolver on the motor, only the newer ones use an encoder. Independent from this, these "old" motor amplis use the +/- 10V input. You can't drive it directly via step/dir, one possible operation is using a simple small DC-Motor driver who have the +/- 10V (or more) as output or you buy a controlunit that can directly work that analog output and have a input with TTL/Quadrature or a Sin/Cos input. The Kanalog should make this and some others I don't know.

[Davey Boy]

Thanks Uli,

Does that mean I could move the motors if I can supply the 10V to the controller?

[uli12us]

Yes, but you need the feedback from the scales. The other problem you have is the spindledrive. Iirc than you have a gear with 3 small motors. thats a bit tricky to bring that to the correct function. Eventually its better you use only one step and change the motor for a bigger with a separate fan who can be controlled with a VFD. The advantage of a geared spindle is, you have a lot of torque in the lower rpms, but its louder than a direct or beltdriven spindle.

[Davey Boy]

At this point if I could even get the spindle spinning, I would be thrilled!

Life's been busy, but I hope to spend some time on this within the next few days. I'm going to reconnect the e-stop and see what goes boom.

[Davey Boy]

You would be better off using a software/controller package that supports the existing AC servo motors and Indramat controllers (which Mach can do with the right hardware, but I'm not sure with your existing drives and motors). I can get more into the technical details if you want.

After spending many hours trying to muddle through the electrical cabinet, I have decided that proceeding in that direction without schematics is pointless. Someone has been into the main Maho control and if it was the same hack that "fixed" the linear scale, who knows what to expect. I really just don't have a lot of faith in the remains of this electrical system.

I understand how the Mach system works, with the breakout boards and such, and feel that if I can rewire this thing into something that makes sense, the machine can be useable again. I do have another machine that is wired to Mach and while it's probably not the most robust system available, it could provide the last few breaths (life support) for this 25 year old machine.

This Maho uses DC servos (MDC type) and I would like to keep the Indramat drives and servos, but bypass the main Maho control system. Mike, do you know what would be a good interface between the Indramat drive and Mach? I guess it would convert the Mach signals to the +/- 10V that the Indramat uses?

All feedback is welcomed.

David

[Davey Boy]

I don't know if anyone is interested, but I have started a new thread to hopefully help my self and others that may be contemplating converting one of these old birds to run with a new control system.

Here is a link to the thread... http://www.cnczone.com/forums/deckel...ho_mh600e.html

Thanks to all for your help!

David

[machineryclinic]

i need constant for maho 600 e2 with 432 control. can any one pl give me constant / parameters please ?

jayesh