DRO with a Logic Output on Zero. Is there such a thing?
Close
Login to Your Account
Results 1 to 17 of 17
  1. #1
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default DRO with a Logic Output on Zero. Is there such a thing?

    I'm looking for a DRO with a logic output on zero that could be used to control an electronic feed drive to make it work like a lathe bed stop or Bridgeport style rod operated trips.

    I frequently use a multi position bed stop on my S&B 1024 lathe and would use the feed trips on my Bridgeport a lot more if they weren't such a pain to get just so. Simple button pushing on the DRO would be much easier. Seems like it could give the single tooth dog clutch on my P&W model B multiple position capability if I rigged up a control rod pusher with motor or hefty solenoid too.

    Seems to be such a potentially useful function when combined with the large number of programmable offsets all modern DRO boxes have that I expected all but the most basic devices to have such outputs.

    Apparently not. I'm blowed if I can find one so fitted except for the top of the range Acu-rite DRO 300 whose brochure implies it might be able to do what I want via an external box.

    If it really doesn't exist is there any other way of getting the capability. Maybe LinuxCNC has DRO capabilities hidden inside. Tangling with Linux CNC looks about as attractive as Brer Rabbits briar patch but if needs must.

    Help and suggestions gratefully received.

    Clive

  2. #2
    Join Date
    Jan 2005
    Location
    The Netherlands
    Posts
    6,800
    Post Thanks / Like
    Likes (Given)
    378
    Likes (Received)
    2019

    Default

    Any DRO for EDM has this feature
    But others also
    You can program it to switch a potential free contact at any number on your DRO So also at 0

    I put these on slotting machines where the powerfeed is electrically stopped
    You can preset the depth then on your DRO and at 0 it stops the powerfeed

    Peter

  3. Likes ratbldr427 liked this post
  4. #3
    Join Date
    Feb 2009
    Location
    Colchester UK (where the lathes used to be made)
    Posts
    2,120
    Post Thanks / Like
    Likes (Given)
    1555
    Likes (Received)
    685

    Default

    Yes it'd be useful to have a zero position output. I thought about modifying my sony (which has a printer output option).

    I suppose the simplest way to mod a dro with led display, would be to detect the negative segment by some means. Of course this will trigger at just beyond zero but that would probably be ok for most uses (as motion detection will always late to some extent).

  5. #4
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default

    Thanks for the advice to look at EDM capable systems. I shall go looking when my Google-Fu is fully charged! Not doing well at the moment.

    Clive

  6. #5
    Join Date
    Oct 2004
    Country
    UNITED KINGDOM
    Posts
    1,549
    Post Thanks / Like
    Likes (Given)
    114
    Likes (Received)
    618

    Default

    I think this is possible in principle. Some DROs support serial data transfer through a RS232 port on the back of the unit. Heidenhain ND780 and Newall DP700 have this facility, probably others. If you can build yourself a simple microcontroller based box, you should be able to use the coordinates output by the DRO to do whatever you want, including triggering a relay on zero or any other XYZ position. I have to say in principle because I have not done this, just thought about it.

  7. #6
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default

    In principle building a box is a fall back option provided I can find reasonably priced DRO console with a data port. Lots of them have the case moulded to take one but the general listings don't seem to offer those variants. Newall, Heidenhain and the other up-market variants are expensive.

    Its a long time since I did any computer programming and I don't fancy relearning it just for one job.

    Looks like the EDM variants only have the output on one axis, Z, which won't do.

    Clive

  8. #7
    Join Date
    Jun 2008
    Location
    VA
    Posts
    811
    Post Thanks / Like
    Likes (Given)
    212
    Likes (Received)
    326

    Default

    I wouldn't want it to stop on 0.0000, then your DRO has to be zeroed off the edge of the part. I think a simple limit switch would be so much easier. Design your switch so it has minimal pretravel before it trips with plenty of overtravel. Then it would be easy to set up vs the mechanical trips where its hard to tell where its going to kick out the clutch.

  9. #8
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default

    Nmbmxer

    The mechanical switch is a good idea which I've seriously considered right up to the point of making first cut drawings. Getting something that works properly every time without compromising normal use of the machine isn't quite as simple as it looks. All seemed a bit too much trouble.

    The idea here is to exploit the offset memory capability of the DRO.

    The Sino DRO on my Bridgeport has 99 memories which I use a lot to define cuts. One is reserved for the parked position as I always put it back to centre travels before shutting down. Next one is the general move around one which usually doesn't have anything special stored. When I touch off a workpiece I shift to another memory register and store that positions as a zero. I store the actual edge position after either correcting for probe diameter or using the centre find routine as appropriate to give the reference zero I'm going to work from. Type the cut into another register and I'm good to go.

    When the count in that register hits zero I know to stop. With the standard Bridgeport set-up I need to stop the auto feed a touch early and finish by hand. If the DRO had a logic output on zero I can use that to stop the drive and skip the hand finish. Hopefully a bit less variation too.

    I know my procedure sounds a bit long winded but its actually quite quick when you are used to it. Big advantage is you have a proper record of exactly what was done so if the job goes wrong accurate stepping back is easy. With the usually embarrassing results. Can't argue with a digital display of exact positions.

    Clive

  10. #9
    Join Date
    Oct 2004
    Country
    UNITED KINGDOM
    Posts
    1,549
    Post Thanks / Like
    Likes (Given)
    114
    Likes (Received)
    618

    Default

    Clive -

    I have had a quick scan of the SINO SDS6 DRO, and it seems to me that some of these low cost DROs with an EDM option do have the ability to output a signal on specific coordinate conditions, just as Peter suggested. I have to say that the manual I read was really poor, particularly in the EDM section where it is obvious that the translator was struggling.

    I get the impression that you already have a typical mill/turn Sino DRO and want to be able to use this.

    Now for some speculation - it is likley that the EDM versions of these popular DROs are basically the same as all the other Sino SDS with some additional components added. It is not usually economical to produce entirely different electronic designs and then completely different different PCB layouts for options like this. It is easy to leave a small part of the circuit board unpopulated for most models but add the additional components for the special EDM models. If we can compare the internal view of the different circuit boards it may be possible just to add these components.

    In addition to the slightly different hardware there may be slightly different software used for the different options. If this is implemented via different ROMs then there will be no real possibility of changing a DRO to provide the EDM function unless the supplier cooperates (extremely unlikley). It is possible howwever that the software is actually identical in all units, but the options are selected and made available in some other way such as jumpers or zero ohm resistors soldered to the PCB. Again comparison of PCBs from different units might show this. I have never looked closely at these DROs so I have no idea.

    Than again you could just buy a Sino DRO with the EDM option. I assume that would be more expensive and you might well lose some of the other functionality, but probably still be cheaper than Heidenhain etc.

    Does anyone have any photos or links?

  11. #10
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default

    billmac

    I've been down that particular EDM rabbit hole concerning the Chinese consoles. Although all the later multi function ones have the EDM button its hard to tell from the instructions if the relay stop function is enabled. As I read the Sino and other similar console instructions the relay control is via a separate 2 pole(?) plug. The pictures I found show no EDM output plug label but they do show a small hole looking around 3mm jack size labelled speaker. ?? Which is probably the EDM stop output.

    RS232 output is very much an option which not only needs an extra plug but also has to be enabled in the software when the device is made. Most cases have the space for the plug.

    They all seem to have the EDM relay output hard linked to the Z axis which makes sense but is of little use on a mill. Might be worth trying on a lathe as a bed-stop option but setting up looks to be a faff. Its not clear if you can store several offsets. Mimbling over whether or not to drop £100 - £150 on one to find out. Even if the relay drive doesn't do what I hope it can always be used as normal DRO to give the P&W metric capability.

    Its almost tempting to see if something could be done with the TouchDRO device. Apparently the latest version can have a USB output as well as the standard Bluetooth so its bit more workshop hardened. One of the included functions is a speaker tone as you approach zero. As the software is open it ought to be possible to hack that routine to give relay drive if running via USB or using a device other than a tablet for the display. In principle it looks as if TouchDRO can run on anything that can do Android.

    But programming just isn't my thing.

    Clive

  12. #11
    Join Date
    Nov 2003
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    6,017
    Post Thanks / Like
    Likes (Given)
    214
    Likes (Received)
    2077

    Default

    Have you tried calling the DRO suppliers and asking about this feature? At least the ones not located in China.

  13. #12
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default

    Quote Originally Posted by EPAIII View Post
    Have you tried calling the DRO suppliers and asking about this feature? At least the ones not located in China.
    Tried calling the suppliers with distressingly unproductive results. "Duh. Why would you want to do that?" being a good result! Acu-rite plus the add on box, high end Newall probably and Mitutoyo maybe being nearest to productive. The Electronic EL400 actually has that capability, sort of, with 6 optically isolated outputs on board but implementation is impossibly clumsy for what I want to do. After the fifth time I got very tired of explaining things to sales folk who had never used the boxes in anger. Amazes me how something so fundamentally simple is seen as a property only serious high end users with matching seriously deep pockets could want.

    Its a pet peeve of mine that multi position travel stops or equivalent functions are universally badly implemented on general purpose machine tools,If they exist at all. Is there any lathe that has native multi-position capability on the cross slide?

    Clive

  14. #13
    Join Date
    Oct 2004
    Country
    UNITED KINGDOM
    Posts
    1,549
    Post Thanks / Like
    Likes (Given)
    114
    Likes (Received)
    618

    Default

    Information about output interfaces from non Chinese DRO suppliers is readily available, published in their user manuals. The information given by, for example, Newall shows the layout of the data packets for each of the axis outputs through the standard D type RS232 connector on the back of the display unit.

    http://www.newall.com/upload/product...81380-uk-2.pdf

    However, the OP is looking for a low cost solution, which means something like the SINO DROs. In these cases only the EDM variants seem to have this capability and the manuals are very poor in comparison.

  15. #14
    Join Date
    Oct 2004
    Country
    UNITED KINGDOM
    Posts
    1,549
    Post Thanks / Like
    Likes (Given)
    114
    Likes (Received)
    618

    Default

    Clive -

    Quote Originally Posted by Clive603 View Post
    Tried calling the suppliers with distressingly unproductive results. "Duh. Why would you want to do that?" being a good result! Acu-rite plus the add on box, high end Newall probably and Mitutoyo maybe being nearest to productive. The Electronic EL400 actually has that capability, sort of, with 6 optically isolated outputs on board but implementation is impossibly clumsy for what I want to do. After the fifth time I got very tired of explaining things to sales folk who had never used the boxes in anger. Amazes me how something so fundamentally simple is seen as a property only serious high end users with matching seriously deep pockets could want.

    Clive
    My last response was to EPAIII, who I thought was talking about information on non-Chinese DRO supplier's serial output.

    Clearly your response was concerned with having the full built-in capability to create an externally acccessible signal based on any axis position, directly from the DRO unit. I do agree that a feature like this, directly settable via the user interface to any axis position on any axis would be a very useful feature to have as standard and not just on EDM versions. I am surprised that suppliers do not see this, but I would guess that you are not getting to people who actually understand the application.

  16. #15
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default

    billmac

    We are certainly on the same wavelength here. Given that everything seems to have 'undreds of offset memories it seems so obvious that an output on zero for each axis would be very easy to implement and very useful.

    Or am I the only guy in the word who sets up my finish cut position as zero, whether in one of the DRO memories or on a feed dial and works down to it! So much less stressful do your thinking first before machining and doing the same thing every time helps avoid mistakes. Even I can see if I'm a full turn out.

    Plan is to get three set-up so Newall et al prices are very much not pension friendly.

    Thanks.

    Clive

  17. #16
    Join Date
    Jan 2005
    Location
    The Netherlands
    Posts
    6,800
    Post Thanks / Like
    Likes (Given)
    378
    Likes (Received)
    2019

    Default

    BTW Do not expext that the powerfeed stops at 0 It goes a bit further
    In my case of the slotting machine it does not matter that much as the tolerances on depth of a keyway is very generous
    I noticed a German DRO system once who had this feature on all axes it seemed
    But I cannot find it anymore

    Peter

    Found it
    It says "4 frei programmierbare relais fuer automat Abschaltmodus " 4 freely programmable relais for automatic stopmodus
    https://www.top-maschinen.de/media/lemundoPdfManagement/815133_KC_Positionsanzeige_ARBAH.pdf



  18. #17
    Join Date
    Aug 2008
    Location
    Sussex, England
    Posts
    3,551
    Post Thanks / Like
    Likes (Given)
    15
    Likes (Received)
    829

    Default

    Peter

    That system looks great. Time to do some digging to find prices and confirm specifications.

    Slight over travel past zero doesn't really matter as, in the real world, its going to be a pretty consistent offset error which can be allowed for. Have to accept that a precision job will need a finish cut. Its not CNC after all.

    Thanks.

    Clive


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •