Retrofit MAHO MH700c with Philips 432 control

and of course

4) Type and source of the photo-diode-array used ?

Thank you

Ralf

edit : found a nearly complete description / diagram included in the master thesis

TECHNISCHE UNIVERSITEIT EINDHOVEN
FACULTEIT DER ELEKTROTECHNIEK
Vakgroep Meten en Regelen
EEN ANALYSE VAN HET
DYNAMISCHE GEDRAG VAN EEN
LINEAIR VERPLAATSINGSMEETSYSTEEM
VOOR CNC-MACHINES
door H.A.Verhoef

last Pages / attachments

(and found the link to this of course in the fix your MAHO thread -thank you Anders)

This also makes interesting reading -while no written in my native language it is still understood 95 %

The reading head used in the documentation is laso a little different from mine (it uses the additional zero inductive sensor) but the photo ic is well documented - unfortunately without the maker.

What I could not yet find is a source for this opto scanner ic -

it is referred to as

OPTO SCANNER

Type : OQ 0005 as documented in the above thesis, stamped as OQ0005 on my ic (see attached photos)
Maker: unknown
Housing : DIL 16 Pin Package SOT-84 ceramic with glass window

Technical data
General
Crystal size 4.9 x 3.5 mm x mm
total sensitive area : 1,8 x 4.4 mm x mm= 7.92 mm x mm
Pitch of the photodiodes : 20mym
Number of groups of photodiodes : 10
Number of photodiodes in a group: 22
Supply voltage max 11V here 8,4 V used.

Hi Ralf,

Have you read my quite long thread over at Practical Machinist? The "fix your maho thread"?

In there you will see that most of us have given up on the Philips read heads, as they don't give out a normal quadrature or any known pattern, but have their own proprietary way of doing this that makes it rather difficult to use for retrofitting to a different system.

Sorry to give you this information, I know most others who have converted their Mahos with these scales have replaced them with standard ones.

Too bad though.... the Heidenhein ones are so fantastic! With the correct converter (EXE) boxes found cheaply on ebay you can get sub-micron resolution. I have 0.1 um resolution on mine now. And I do have the original correction sheet from the manufacturor I can insert in a correction file.

One important thing worth knowing: What year is your machine from, and does it have brushed DC or brushless servos? This is a rather big difference!

AKB

thank you for your fast reply.

Yes , these units have their own kind of output - some kind of PWM modulation as per description by Sascha Ittner (pdf on Github , diagrams recorded by Nick Müller).

If I should convert to Linixcnc , I would like to keep the Philips heads with Sascha´s solution (Head through wall )

But at this time I just want to make it work again with the original system.

And yes - brushed motors Indramat (8 Brushes each tacho + motor)

And there is a company in eastern Germany that can repair these heads - at a price I guess I am not ready to pay.
So I bought a used one today for 150€ and hope that will be it for the moment.

BTW the ir-LED is working - Could observe it by means of snake cam and Raspberry noir cam - not with iPhone cam (ir - filter).

Still I would like to know who the maker of this photo array was and if it is still available ....

I should reread your thread -- sure more economical / practical way to do the things ...

Thank you

Ralf

Hi Anders ,

still reading that thread ....

hours ....

but excellent stuff - too bad I found it that late .....


Thank you for starting it

Ralf

schamatics -- that's a good one )