What DRO to get?

[DazzaParticipant @dazza]

I normally don't reply much on forums, but I recently purchased a 4 axis magnetic DRO system for my new Warco VMC mill. I got it from EMS-I in Lancashire. They have a EM750 LCD read out that has 4 axis display and any 2 axis can be summed together. Not the cheapest DRO system but seems very nice so far. I'm just starting to fit the magnetic scales to the VMC over the Easter holidays.

[GordonHParticipant @gordonh]

Posted by ken king, King Design on 18/04/2019 11:55:58:

Garry mentioned hearing of someone who was able to fit scales to both quill and table raise/lower, and have them combined as the Z-axis readout. I asked if this was possible but both suppliers apologised and said it wasn't. It's something to think about though.

See https://www.machine-dro.co.uk/m-dro-linear-encoder-summing-interface.html for combining quadrature interfaces

GordonH

[BikepeteParticipant @bikepete]

Posted by ken king, King Design on 18/04/2019 13:36:13:

The notion of combining both Z-axis motions in one readout is an ideal still worth pursuing, and I haven't given up on it yet. Gary, can you recall where you heard about it ?

I'm not Gary but I looked into this a few years ago too.

Short answer: buy one of these M-DRO "Summing" boxes and compatible DRO console and scales

Long answer: You need either

(a) a three axis console with a "summing" box as above feeding the Z input; or

(b) a DRO console with four inputs and the capability to "sum" two of them to display as Z. At the time I looked there were few options for this apart from some higher end models from Newall, and some top end models from e.g. Heidenhain (sit down for the price). But maybe in recent years that's changed…; or

(c) something like the now apparently discontinued M-DRO PC Interface Kit which had four inputs and (IIRC) Windows software that could do the 'summing' before displaying it on a PC monitor.

First option looks most realistic now.

[DazzaParticipant @dazza]

That's a separate box which would be great if you already had DRO fitted and wanted to add a 4 axis to you existing read out. The EMS-I EM750 LCD read out does the summing internally, minimizing the amount of cables and connections required.

[Henry BrownParticipant @henrybrown95529]

Following recent comments with interest as that on my to do list soon…

[JonParticipant @jon]

Or you could buy a universal 2 axis and a mill 2 axis readout.
Using universal for both Z.

All my Sino glass 3 on mill and 1 on lathe plus the magnetic are still going 9 1/2 years on pro.

Have seen the Indian made EMS there pretty good.

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