Vintage Heidenhain DRO

Has anyone come across or used one of these before.

I am struggling a bit with working out the functionality beyond the basic readout function (which itself has some foibles, like not being able to change the value of the existing position information when you switch between inch and mm), and preset system.

To their credit Heidenhain does have the manual for this 33+ year old DRO on their website, but the description of how to use the memofix system is pretty obtuse to say the least.

Given that it's a product of West Germany it is throughly before my time, but it occurs to me that quite a few forumites may well have experience from using these dating back to when they were still state of the art.

There's a distinct temptation to just swap it for a modern DRO, but it seems a shame whilst it still works.

With it being Heidenhain (and old) it uses sine-wave scales, it would mean new low-profile scales or sine-wave to TTL conversion boxes, neither of which would be be cheap (or buying a compatible counter unit from Newall, Mititoyo or Heidenhain for more than I paid for the mill itself!).

If I find it workable I will most likely just get a cheap single axis Sino DRO to add z-axis, (possibly using a summing interface and scales on both knee and quill).

Edited By Jelly on 20/04/2023 19:14:18

Realistically its just a pretty set of LED numbers to be used in place of the dials.

Important to remember that these things are not a DRO in the modern sense. They are basically just position measuring devices using optical scales and pulse counters rather than lines on dials or rulers. I've used the single axis versions in scientific and engineering devices. Marginally simpler but still a right headache.

For all practical purposes you drive the machine in the same way as you do with dials making notes of the readings where appropriate. About the only gain is that you don't have to count turns as the readout counter scale is continuous.

Preset and memofix functions are basically designed to cause your brains to leak out of your ears! Setting things up to get the results you want takes major league concentration and keeping track of what you have set is even harder.

The issue is that for all practical purposes the display and its driver is completely separate to the counter gubbins which in turn is completely separate to the actual scale drive and sine wave to square conversion circuitry. The counter just increments up or down from wherever it is depending on direction.

The display driver just holds the last value. Inch or mm output conversion is done on the fly by selecting a suitable divider chain in the counter side of things. Which is why it can't convert a position. The display only knows the number.

Preset simply allows you to force number into the display driver which subsequently goes up and down following what the counter does.

Memofix lets you define the counter starting point from a fixed, reference, position on the scale. You can put your own values in to offset it as need be. The red light in memofix mode essentially means that the counter doesn't pass any values to the display once it has passed over the reference mark on the scale. So you can preset anything you like and the number won't change however much you move the scale. Green light means the scale output is being counted but it doesn't increment the display until you go over the reference mark again.

Not enough money in them world to pay me to use one!

Clive

Edited By Clive Foster on 20/04/2023 20:03:59

I think you have confirmed my suspicions there.

It works and is far more convenient than dials (especially with the dials being in inches but all my tooling and edge finders being metric) so no rush to replace it, but I think replacement is probably warranted.

Still seems a bit of a shame to scrap it, I wonder if there's any vintage electronics bods who would find it an interesting addition to their collection.

I guess the question now is if sine wave to TTL convertors are cheaper than new 500mm and 1600mm 2μm scales.

Edited By Jelly on 20/04/2023 21:42:52

Used one on a Bridgeport many many years ago, horrible thing, we only used that mill if we really had to, all our other Bridgeport’s had Anilam or Newall readouts. Never liked Heidenhains CNC control system either.

It's a fairly basic DRO. Used one 15-23 years ago on a Bridgeport. It is OK when you get used to it. Basically you can just add or subtract enetered values from the current reading.
Memofix uses a electrically signalled reference position, typically center of travel. Passing this can stop or start the counter. It can be used offset a zero datum. Basically you zero at the reference, touch of you datum and then subtract the difference from the reading. I never found it usefull.

Robert.

As Robert says using preset /memo-fix is essentially no different to setting adjustable dials so you have a convenient number to finish or start a cut from. Such as my common practice of setting dials on the lathe to "finish on zero".

Memofix is machine referenced whilst preset is work referenced.

If dials is all you have or have used it is step up., But a small one. Like the cheap capacitive scales based on digital caliber technology.

Risky to keep the scales as you don't know how much life the illuminator has left. Underun bulb as standard in the old ones so they last a long time but changing is tricky and, as I understand it, the proper bulb is expensive. Folk talk about LED conversions but how good / easy that is I know not. The scale needs a very even illumination to function properly.

Agree with Baz that the Heidenhain reputation somewhat exceeds the reality of execution. The scales and probes are excellent but the electronics more than little clunky.

Clive

I had an old Bridgeport with this unit and the same manufacturers scales, this does not really answer your question, apart from the fact I found it ok to use, much better than dials on a very worn machine. Buit this might help out others, or yourself who have this set up. The display red LED display used to get brighter and dimmer, almost flashing although you could just about use them. I contacted a company that offered a repair service and they wanted a couple of hundred quid in advance to even look at it, plus the repair cost if it went over two hours, almost as much as the mill cost!. Took it to our electronics guy at work and he diagnosed faulty capacitors on the circuit boards, some could be seen to have leaked, there were quite a few but they only cost a few pence each from Maplin ( it was a few years ago!) and hey presto we were in business. The slides were however unreliable and on inspection were gummed up with old coolant, on the basis of nothing to lose i took them apart and cleaned it all with isopropyl alchohol and they then worked perfectly. Used it for a number of years sold it to a mate and I know it's still working ok. So worth persevering with if you can get used to the slightly strange way they are operated. Read lot's of warnings about working on the slides but just did it very carefully, and I'm a ham fisted bufoon when it comes to anything delicate! Sorry to have kind of hijacked the thread a bit but thought it might be of use to someone.

Dave

Our Bridgies had its predecessor, optical readers on the slides. We had a log book with the various calculated scale settings from a designated 'Zero' point to machine whatever. No electronics, pure mechanics, only the bulbs to fail and were easily replaceable.

Regards Ian

In my working life I operated a Bridgeport with this set up. never did understand the memofix function.

My home workshop Bridgeport has the later Heidenhien readout but the scales will not work with the latest consoles so a complete new system if anything fails in the future.

Never thought of that - I shall have to try it! Very educational this forum.

Dave

I had a Heidenhain DRO even older that yours, mine used a 4040 microprocessor, look to see what yours uses because it might be quite valuable. The 4004 was the very first microprocessor in 1970.

I have a 731 without memofix, very basic, had to replace a bulb with an led. it now only works reliably in one direction and loose track on the return.

Correction to my post above...

Had a text message from Neil the electronics expert that changed the capacitors in my DRO head, who is also no mean model engineer..

I quote " Dave I realise you firmly believe everything below 11KV is insignificant but those capacitors I changed in your DRO were actually diodes, and the marks on the pcb were not where they had leaked dielectric, but smoke"

That's me told then, sorry if I misled anyone.

Dave