DRO is driving me crazy.

Ian - "whole workshop and machines must have been drenched" .

This was not the case, the only signs of condensation were as I have described.

Rik

PS Jon - If you have the time / inclination to PM me re: a certain machinery supplier I would be happy to respond.

Rik

I do not doubt your description, also the fact that the DRO is working and the problem resolved is what matters. I'm just at a loss to understand the physics of how water was only found at the battery contacts.

When you started this thread you were experiencing error related to switching the machine on and off, did you ever solve that problem and if so, how?

As it seems to be a not uncommon problem, what you did to fix yours would be useful information to relate here.

Ian P

At least it's gradually reducing

Neil

Ian - I am as puzzled as you are as to why I only found water traces on the lithium cells and battery contacts but nowhere else. I really have no explanation. I am just glad I found out what was causing that particular problem.

When I started this thread I reported that it seemed that errors occurred on the DRO heads up readout when cycling the power on and of using the ON/OF buttons on the control box. It is early days yet but I think I may have accidently discovered a way of mitigating the problem. So how?

Some weeks ago the speed control board went bang and I had to order another. After installation of the new board I noticed that with the speed control knob set at its lowest setting a press of the power on button simply illuminated the speed display but the spindle did not rotate. Only after rotating the speed controller a few degrees clockwise did the spindle start. Looking at the documentation for the board I could see that this could be corrected by adjusting one of the miniature pots. But I left it as it was because I had a cunning plan.

Before the big bang the readout used to periodically loose its marbles - as previously explained - when pressing the STOP button. I began to wonder if this button was arcing and causing the read out anomaly problem. What got me thinking though was while chatting to a bod at WARCO, I mentioned the read out problem whilst ordering the new board. He told me that the speed controller should always be returned to zero position before both starting and stopping the mill (and the lathe as well). Mine is not to reason why so I have complied.

Its early days yet and I have not used the mill very much since fitting the new board but I have stuck to WARCO's advice. I have also left that mini pot set as received and so far I am pleased to say I have not had any more read out faults when powering up and down. Fingers crossed then !

But life is never that simple is it? As I said earlier I have not been using the mill a lot since fitting the board and during these periods of non use I have disconnected the mill from the mains but left the DRO switched on and set at zero on the X and Y. Four times in the last couple of weeks the zero has changed to a random reading without me touching anything. If I had any hair I would have torn it out by now

Rik

Rik,

Forgive me if I labour the point, but I think it's worth directly quoting from the link that I re-posted yesterday:

• At 2 March 2012, 10:30:16 user Hans U. Meyer wrote: [reply @ Hans U. Meyer]

• Here's why the Chinese Caliper's binary output is not to scale: I designed it for Sylvac in 1982, when the small number of on-chip transistors limited the options. Hence a scale pitch of 5.08mm=0.2inch, easy to subdivide in both metric and inch with serial binary (LSB first) arithmetic logic. The same logic also calculated the serial BCD output in mm or inch for the display. The serial binary signal, common to both units, was output as an afterthought: only few people wanted it, to which Sylvac simply sold binary-to-BCD-to-RS232 adapters.
  
  Chinese calipers use very, very similar chips (and that's an understatement). One foundry must have modified it to output BCD instead, I think it's the ones Aldi sold in Germany. The display switch-off feature was added as a gimmick by others, as obviously there is a sucker born every minute (good marketing!).
  
  The moral of the story: have fun cutting jaws of Chinese calipers and selling homemade DRO kits to the DIY market! As for me, I've been there, done that, and moved on a long time ago. Calipers from Sylvac and other manufacturers (including Chinese ones) are now inductive (insensitive to coolant) and have an RS232 output with galvanic separation. Talking about this, those old directly coupled 1.5 volt interfaces are very sensitive to ESD and ground loops; I wouldn't want them on a machine tool.
  
  That's all for now.

_____________________

.

This may or may not explain your problems ... But it's a very good place to start.

MichaelG.

"But it's a very good place to start."

Forgive me if I have missed your point - were you trying to make one?

Rik

Good question Rik.

If I had Hans Meyer's bank account I would not use DROs based on capacitive scales.

Ian P

I have several DRO setups in my workshop, modified cheap calipers on a tailstock, iGaging scales on a mill, and a glass scale system on the lathe. All of them are 100% stable and all stay switched on continuously (iGaging batteries last up to 2 year). Unheated attached garage workshop (fan heater sometimes). If I had a choice I would prefer Newall or similar kit but so far I have had no real trouble with the cheaper stuff.

Ian P

.

Only that Hans U. Meyer, as the inventor of what we now call 'Chinese Scales', might be making some valid points in his remark: "those old directly coupled 1.5 volt interfaces are very sensitive to ESD and ground loops;"

MichaelG.

Don't mind me ... I'll stop interfering in this discussion.

Edited for clarity.

Edited By Michael Gilligan on 27/01/2016 20:55:40

I recently bought the SPG version of the Warco and it mentions that at least twice in the user manual AND there was also an A5 sized laminated notice cable tied to the actual machine saying the same. Apparently they've decided stopping and starting at other than zero on the speed dial is the main cause of board failures.

I'm not suggesting that you don't do as they say but having to return a speed controlller to zero in order to stop a motor sound to me like cheaply engineered electronics. I would expect 2 methods of stopping rotation. A normal stop button which would reduce the motors speed in a controlled fashion from the 'process variable speed' set by the speed control knob down to zero and then turn the drive outputs off. The second button should be the emergency stop which should immediately turn the output to the motor off. Normal use should use the first button.

Any machine with electronic speed control that only has the single way of stopping is to my mind a fudge and likely to cause issues with either the drive unit as suggested already and or mains spikes and radiated noise into other electronic systems local to the machine.

When I design anything if I don't want the operator to do something I ensure that the electronics wont let them.

regards Martin

"I recently bought the SPG version of the Warco"

Thanks for that info Mick. You have confirmed my suspicions that in my case the replacement of three boards in less than three years could have been avoided had a caution plate been screwed to the front of the machines indicating correct start /stop procedure. An aside remark to this effect in the mill handbook is NOT enough. A component critical procedure such as this should be explained and emphasised in very large capitals - more than once !

Rik