View Full Version : Need Help! DMC 70V Encoder problem

11-28-2009, 08:15 AM
Hello guys,

I have a problem with the spindle encoder of a DMC 70V (dialog 112)
The machine stopped at the middle o the program and say s01 servo alarm spindle

Restarted the machine. Can run the spindle but when i give a rpm i can't change it anymore.
Machine says that spindespeed is not reached.

Called a mechanic says that the encoder or drive unit is broken, called to dmg, the will come tuesday and say that the complete spindle has to be removed en when the drive unit is broken it will cost between 15 and 25k us dollars.

I really can't afford that amount of money. I bought the machine about 5 months ago.
Now i saw the thread from adrenal who replacing the spindle bearings from this kind of machine.

Does anybody know's if the encoder can bought seaperatly and that i built the encoder on the spindle by myself or another mechanic than DMG
I have the feeling that DMG is robbing me. Normal a encoders cost about 500 dollars till 1K.

Hope somebody cann give me some help i what the best thing is to do.
It's a franz kessler Spindle DMS 110.AL.4FOM encoder should be from gib(in the manual) but i think its sizag

Don't know of it's possible to buy a encoder directly from franz kessler, or the have made a contract with DMG

Thanks in advance

11-28-2009, 11:06 AM
I am not familiar with that machine, but generally there is pulse generator or encoder on the motor shaft back to the drive for speed control and also one on the final spindle shaft, this is to synchronize the Z axis etc.
As a rule, the encoder on the spindle does not cause a spindle alarm.
If it is a spindle alarm, then I would suspect the device on the motor first.
Generally drive manuf. do not make encoders but use other suppliers for these.
Heidenhain are one of the largest, especially if a European made in machine.

11-28-2009, 01:45 PM
The spindle alarm went away when restarted the machine,

When i restart the machine i don't get any error,
Now when i give spindle speed in i can run the spindle, with the message spindle speed not reached. I can't change the spindle anymore

A mechanic checked the speed and the speed is exactly what i put in.

Normally on the diagnostic menu there is parameter cyc cnt (p) normally +/- 15 digit nr which changes if i turn the spindle. At this moment it is zero.

here a pic of the spindle of adrenal with a dismounted encoder.
Should be almost the same as my machine


11-28-2009, 01:58 PM
That appears to be a proximity type pulse generator similar to Mitsubishi use etc.
Notice the toothed wheel.
The Mitsubishi style have to be aligned and gapped using a double beam 'scope, although the one you show appears to be a simpler design.
The pre-amp that has to be aligned is situated approx where the black box is under the 4 terminal strip.

11-29-2009, 08:11 AM
Been working on machine today,

I'm a little further now,
I can remove the encoder without pullung out the spindle.

Have to wait till tuesday that DMG can confirm or my encoder is faulty or my spindle drive.

Big change that the encoder has to e exchanged by a newer model with a new bracket. i hope that DMG will sell that or a reasonable price.

Only at this moment i dont won't to pull the encoder loose to see wiich brand it is till i know or sure that the encoder is faulty, normally encoders are fragile

11-29-2009, 11:09 AM
When you say encoder, are you talking about the inductive pulse sensor on the end of the blue cable, these are usually more rugged than an optical encoder.

11-29-2009, 12:07 PM
I got a different kind of animal.

This is a pic of the pulse sensor, maybe encoder wasn't the good word for it, but i'm not a real technician.

A service technician left me with a new one laying at right know home, its for a kessler spindle he didn't dont know or it will fit of give the right output signal for de spindle module. This pulse sensor cost aprox 300 euro
That is the choice of the DMG mechanic


I'm glad i don't have to pull the spindle it would take one day work

When you say encoder, are you talking about the inductive pulse sensor on the end of the blue cable, these are usually more rugged than an optical encoder.

11-29-2009, 12:54 PM
Technically it is an encoder, albeit an inductive one, is there any electronics on the board it appears to be mounted to?
Usually there is a procedure to set the gap between sensor and wheel.

11-29-2009, 01:28 PM
Yes there is al small circuit oard before it goes to the spindle module, big change that that isn't necasary anymore.

The size off the encoders are a lot smaller is the present.

Yes there is a proceduce to mount the encoder, there also a small stroke off metal which is the distance which of pulse sensor has to free from the hub. The tolerance of the gap between the pulse sensor and the toothed hub should be about +/- 0.02 mm. The distance depend on the type of encoder and hub and aprox 0.15 till 0.2mm also the pulse sensor has to be mounted straight en may not have to many angle error. You have to mount the encoder straight en against the hub and remove the thin sheet metal part. and it should be on the correct distance and there has to be a reference tooth on the hub which you have to care with. This is what my technician said today

I don't gonna mount the encoder. It has to been set for right spindel orientation for the ATC. and i don't know which parameters you have to adjust with the dialog 112 control.

for now fist make the lathe work done

11-30-2009, 10:42 PM
Prolem solved, it wasn't the encoder the control was locking the encoder signal

Up and running again

03-23-2010, 08:17 AM
Thanks for sharing your thoughts with us

03-23-2010, 03:16 PM
try EDMR .co.uk they repair the spindles

03-23-2010, 09:05 PM

The problem was that the machine gave a spindle alarm when he was switching the tool. When i restarted the machine the gripper from the atc was 180 degrees turned.

the mechanic did turn gripper back you can do that in the service menu and that's was all. Did had it one time again, but can do it now on my one.

just for info and it can safe somebody a lot off $$$$$ DMG mechanics aren't cheap.