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[Source] Lm10 Renishaw Mag Linear Scale Replacement Vendor Spec.

Discussion in 'CNC IN THE HOME SHOP' started by countryguy, Aug 3, 2016.

  1. countryguy

    countryguy United States Active User Active Member

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    From another thread I was chatting about sourcing a replacement for the the renishaw LM10 that Jim knows and loves. I've been itching to upgrade a few of my setups to these types of scales. A used Lathe that needs scales, My BP 815 tool room grinder, my smaller 3:1 mill, needs a good quality scale.

    ...so the doallrs rack up quick on this stuff. The US/UK equivs in the 1um and 5um magnetic pick-up/tape class that are just out of my price range so I opted to start some dialog w/ the following folks:
    http://tinyurl.com/ditron-mag-scales we'll see how this goes and I may pop some Q's up here if I get in over my head :)

    Thanks and have a fun day all!
    CG .
     
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  2. JimDawson

    JimDawson Global Moderator Staff Member Director

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    I'm a little confused by these specs. Maybe it is a poor translation. In your conversation with them maybe they can clarify.

    Basic Specification::
    1:The accuracy:+\-10um,15um,30,um

    Specification of DM series magnetic scale
    5:The magnetic scale can output grid digital or analog signal,it can output a series of resolution with 1um,2um,5um,10um,20um and 50um,which can be selected by customers.When the resolution is 1 um,the highest traveling speed can be 4m/s
     
  3. Tony Wells

    Tony Wells United States Vice President Staff Member Administrator

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    Sounds like one of those accuracy vs resolution issues.
     
  4. JimDawson

    JimDawson Global Moderator Staff Member Director

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    It would be interesting to do a direct comparison with the Renishaw equipment. I just happen to have the equipment here to do that. I am able to compare the accuracy over about 2 meters and to 1 um. This is not to say that I would be able to prove the absolute accuracy, but rather just compare the end values over distance.

    Let me know when you get pricing information. I need more readers also.
     
  5. countryguy

    countryguy United States Active User Active Member

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    Hi all- The Ditron folks replied w/ the following note below in blue. I have sent another note to Delos for quote and left it open for all parties to reply upon (ouch... last time I did this I was slain w/ alibaba' email for months. But hey- I need these. :) ) The prices from Ditron are about 2x what I think I am willing to pay. As soon as I find a source for a read-head around the 50-70$ mark I'll get a sample in the door. Or is that just wishful thinking?

    My plan is to just use the Yuri's toy's DRO display based on the $12 arduino my Daughter turned me onto playing with recently. (love having future engineers in the family!) http://www.yuriystoys.com/p/android-dro.html & http://www.yuriystoys.com/p/arduino-basic-dro-controller.html

    According to that (my email w/ the LM10 spec),we can supply you the magnetic tape and magnetic read head.And the same sereis model of product is DM-A open type magentic scale

    LM10=DM-A
    And our Magnetic read head is RS-422 output signal, A/B/Z A'/B'/Z'
    output signal resolution
    1)DM-A-300mm RS-422 5um 150USD

    2)Magnetic tape-5M 5um 150USD
    3)Read Head RS-422 5um 125USD(DB9)
    4)D60-3V 111USD
     
  6. JimDawson

    JimDawson Global Moderator Staff Member Director

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    Not a bad price on the tape if it's 2mm magnetic line spacing. The RS422 output is good. I wonder what they are offering for a 1um read head. In the ad, they alluded to a programmable read head, including a 1um resolution, I wonder if this is the same. If so then it should output 1um resolution. 5um resolution would give you 0.0002 inches at best, not adequate in my book;)
     
  7. countryguy

    countryguy United States Active User Active Member

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    :) Jim, Jim, ever the-guy-of-uno-tenth' Inspiring! :) K, next update: I did get a few more replies back. Plus I will clarify w/ Ditron what they have going on. Here are the other 2 I sent. 3 total. The #3 quote from Delos looks pretty reasonable! I would wager there could be a little wiggle room here as well, but those prices look the best so far.

    From: Michael Li Shenzhen Hengxingxing Precision Instrument
    Hello Mr.Jeff,
    Good afternoon.
    Sorry for replying late, I apologize to you.
    Here is the quotation for the goods you need:
    The total price is US$ 590.00
    including:
    /3 axis digital readout(type:GCS900-3DA)--1 piece
    /Magnetic scales, 5 micron---3 pieces
    300mm
    600mm
    1000mm

    Here is the quotation for the goods you need:
    The total price is US$ 253.00
    5 Meters of magnetic tape

    Here is the quotation for the goods you need:
    The total price is US$ 140.00
    5 micron magnetic read head with plug/connector

    ==============================
    Shenzhen Delos Electrical Science & Technology Co., Ltd.
    Dear Jeffrey,
    Thanks for your interest in our products.
    For the magnetic scale and the price as follows:
    1.300mm magnetic scale:$110
    600mm magnetic scale:$122
    1000mm magnetic scale:$135

    2.5000mm magnetic tape: $180
    3. Magnetic sensor : $85
    4. 3 axis dro display: $80
    5. The cheaper for this kits is linear glass scale.

    Best Regards,
    Luca
     
  8. JimDawson

    JimDawson Global Moderator Staff Member Director

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    I like my inches divided by 25,400 :grin:
     
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  9. countryguy

    countryguy United States Active User Active Member

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    hahaha. That was funny! good reply! OK, I've sent notes back to Delos and Ditron. Delos seems to be the biggest name as I have found their stuff for sale on several other big sites globally.

    sidebar:
    I have a question on what I need for the new Andreychow lathe I have. If I am going to place an order w/ China and pay some shipping- I may as well put the big new Lathe DRO and some glass scales in there. Do you usually see the long scale for Z on a lathe go the entire way? or is 30-40" the rule of thumb? On X" I'm unsure how long you usually make that also?
     
  10. JimDawson

    JimDawson Global Moderator Staff Member Director

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    I guess I would make the scales the full travel length plus a little bit on both axis, so you can have a bit of over travel on both ends.
     
  11. countryguy

    countryguy United States Active User Active Member

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    Here is a short update. I am going to move ahead with several Mag -Scales for the shop and Arduino projects from Ditron. They have been really great to work with. Quick replies. Answered everyone of my questions, and want to serve the customer no matter your size. (so I think).
    I attempted to communicate with over 8 places via Alibaba. Only 3 came back with products and pricing. IT was quickly narrowed down to 1 based on products in 1um and prices.

    If anyone wants to know my Acount Mgr. there- Just let me know in a PM and I'll shoot his name and contact info over to you. I am not sure I can really verify these down to 1um next to an LM10 w/o actually buying one... But we should be able to figure out some pulse counts or something??? The fun is in the learning and challenge huh! I guess I do have a few Q's in the text below if anyone wants to chime in there.

    What I'm getting:
    1)DM-A-300mm 1um qty 2 (Arduino DRO project w/ grinder).
    2)D60-3V 3axis Qty 1
    3)D60-2V 2axis Qty 1 (home lathe project)
    4)DM-A-270mm 1um Qty 1 (home lathe project)
    5)DM-A-1200mm 1um Qty 1 (home lathe project)
    Shipping cost FedEx 128USD 2-4work days
    The hole thing is under $1K as far as pricing goes, they beat anything I could find online anywhere.

    My 1st question is about 1um. Is 1um just too much scale for a old 70's engine lathe? No ball screws and can I even glean to 1um? Just wondered. The costs from 5um to 1um was just a $40 bump if I recall - So not much! and I believe it was in the tape. Not the head?? (to confirm).

    I went w/ the MD-A style setup as they have a much slimmer profile, are IP67, and noted as typical for lengths under 3300mm.

    Anything else to wonder, worry or concern myself w/ at this point?


    Magnetic%2Bscale (1).jpg Close%2Btype%2BDM-B (1).jpg DM-A (1).jpg
     
  12. JimDawson

    JimDawson Global Moderator Staff Member Director

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    I don't know any other way to do it. The only way I can think of given the equipment that we have to work with is to do a side by side comparison, count pulses and look at the difference over a long distance and just assume (a bad assumption;)) that the Renishaw is the standard. If we had a full metrology lab, then we could do an absolute comparison against a tracable standard.

    I just round to the nearest tenth, you can always put a piece of tape over the 4th digit :rolleyes: I suspect it is in the head, the standard tape has 2mm spacing on the poles, but I have seen 1mm tape. All of my tape is 2mm

    I think you have it pretty well covered.:)
     
  13. countryguy

    countryguy United States Active User Active Member

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    Thanks Jim!!
     
  14. countryguy

    countryguy United States Active User Active Member

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    A Great way to end the weekend- Ditron shipped my order in 2 days, FedX took 3 days to get it from there to here and is already scheduled for tomorrow delivery. Monday seems brighter already!
    signed : Kid at Christmas! :geek:
     
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  15. codymnelson

    codymnelson United States Swarf Registered Member

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    So what is the verdict on the Ditron MD-A scales? Your lack of follow up on this is kind of scary. I hope everything worked out ok...
     
  16. JimDawson

    JimDawson Global Moderator Staff Member Director

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    I finally heard back from Ditron on the 4th of Jan. They said they were waiting until they had a LM10 1um equivalent. They say they have it now but I haven't ordered a sample yet. I'm going to order a read head and 2 meters of tape.
     
  17. countryguy

    countryguy United States Active User Active Member

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    I too was contacted by Ditron as a follow up. I have gotten to know the Sales guy. His name is Jeager and is very responsive. The new read-head offers better distance to tape, and read speeds needed for CNC rapids. Those were the two main items from my conversations with them. I am due to put on an X, Y, and Z positioning setup for my Centroid controller. I just need to get some time. Anyway, Jim is the real authority, and since the LM10's have all but dried up, we'll see where this goes. Jim, I'll send Jeager a note as well. IT's been a crazy few months for me. Just no time w/ the new job.
     
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  18. middle.road

    middle.road Active User Active Member

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    Ok, just read through these couple of threads.
    I'm back on my DRO quest for the Bridgeport, never did find a Mitutoyo replacement scale for the wrecked one.
    Take-a-way: Pay attention at the auctions for LM10's (we shall not bring up the auction back in Nov. - I really wish I knew what I was doing...)
    I know of Renishaw from back in the days on CMM's and such, had no idea they also did encoders.

    what are their RGH encoders products in comparison to the LM10s? There are several up on fleabay right now.
    Speaking of which I ran across this tape from a seller in ATL. -=- LINK -=-
    Also ran across this LM10 wanna-be. -=- LINK -=- Price is a tad high perhaps. Had a couple of other items that reference LM10.

    I toying this week working on the cost of this type of encoder(s) using TouchDRO for the Readout vs. imported glass scales.

    I wish there was a way to fab a replacement 'X' scale for the Mitu readout, but I haven't figured it out.
     
  19. JimDawson

    JimDawson Global Moderator Staff Member Director

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    As far as I can tell there is no functional difference between the RGH20 and the LM10, only a different form factor.

    I haven't looked through all of the RG20 units on ebay, but the ones I saw are RGH20D-xxxxx, the ''D'' meaning 5um (0.0005 resolution) To get 1um resolution it would have to be a RGH20X

    The LM10 clone seems to be priced a bit high. Who knows about quality.
     
  20. JimDawson

    JimDawson Global Moderator Staff Member Director

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    OK, I have a Ditron 1um read head coming, should be here mid next week. I'll get it tested and post the results.

    Stay tuned.........:)
     
  21. Al-Hala

    Al-Hala Canada Active Member Active Member

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    While I cannot speak to the magnetic side, I have recently purchased a Ditron 11F (1um) optical scale, and was somewhat of a mixed bag. Although advertised as having an index of 50mm per piece, the actual received spacing was double that, at 100mm between zones. In addition, the zones were not centered around the nominal midline of the scale, but offset. Both were confirmed to be factory current practice. Having said that, the scale does seem to operate to the other specifications. It made me wonder about others experiences, so it will be enlightening to see what you get, Jim.
     
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  22. middle.road

    middle.road Active User Active Member

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    heyO, any chance we can get a link to what you procured? I'd like to see the specs. I still have not gotten anything setup for mine.

    _Dan
     
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  23. JimDawson

    JimDawson Global Moderator Staff Member Director

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    The attached PDF is all I have. There is no internet link that I can find.

    The specs really make no sense, a poor translation at best. Once my testing is complete, I'm going to send them new specs that are actually readable in English.;)
     

    Attached Files:

    • DM.pdf
      File size:
      1.4 MB
      Views:
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  24. middle.road

    middle.road Active User Active Member

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    Dawson Controls Translation Services, INC. ???

    That is some poor technical describing ...
    Thx!
     
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  25. JimDawson

    JimDawson Global Moderator Staff Member Director

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    My Ditron MR200 read head just arrived! From the outside it looks good. The finish on the head is not as nice as the Renishaw, they could have used a bit finer emery cloth to finish it. Also the sensor surface does not appear to be flat, I'll check it with an indicator later. Has a 3M armored cable with a 9-pin D-sub connector. I wanted it with flying leads with a color code, but I guess this is what they had. I need to figure out the colors so I can wire it in after I cut off the plug.

    upload_2017-4-4_15-42-20.png

    Now out to the shop to build a mount and get it onto the router so I can test it.

    Stay tuned..........:)
     
    Last edited: Apr 4, 2017
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  26. JimDawson

    JimDawson Global Moderator Staff Member Director

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    OK test time.:cautious:

    I ordered this with flying leads, but they shipped it with a 9 pin D-sub. No problem, I have wire cutters. :grin: The wiring looks very professional. The cable is high quality with 4 twisted pair, with both foil and braid shielding.

    upload_2017-4-5_13-7-54.png

    Here is the setup. First find a hurricane tie and modify to become a read head bracket. Fortunately I had enough extra length on the tape to accommodate the extra head.
    upload_2017-4-5_13-13-2.png

    upload_2017-4-5_13-13-42.png

    I had a bit of trouble setting the spacing, the Ditron head is a bit more sensitive to spacing than the Renishaw. I wired the Ditron into the W axis on the machine, that way I could read it on the DRO.

    The test consisted of running the router from 0 to 96 inches and back for a bit over an hour. Then will compare the Ditron position to the Renishaw position on the DRO. I don't actually know it either encoder is reading the absolute position correctly, all I can do is compare the readings.

    I do have a high degree of confidence in the Renishaw reading because I have been able to hold +/- 0.001 on machined parts on the router, and < +/- 0.0005 on the mill. On Alloys Shizuoka, equipped with the same Renishaw readers, we were able to achieve 1um roundness in circular interpolation, on a 4 inch circle. This was checked with a 1um resolution CMM. In that case we were looking for deviation rather than a specific size, but as near as I could measure it with calipers, it was exactly on size.

    I zeroed out both encoders, and pressed Go
    Here is the test G-code
    %
    G0 Y96.0
    G0 Y0.0
    M47 (repeat)
    %
    The best speed I could maintain reliably was 150 IPM, but I did take it to 200 IPM during the test, I really need bigger motors on my router.:(

    So at the end of the test, about 10,000 total travel inches, the Renishaw was reading -0.0001, and the Ditron was reading -0.0007. Yeah, I can live with that.:cool: I'm going to call this a success. :encourage:

    I'll leave the Ditron connected and do some comparisons on the next job I run on the machine.
    .
    .
     
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  27. middle.road

    middle.road Active User Active Member

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    How much did the Ditron cost?
     
  28. JimDawson

    JimDawson Global Moderator Staff Member Director

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    $90 + $28 Fedex shipping from China.

    A little update, I ran an air cut of a large job, and the Ditron seemed to track just fine. Within 2 0r 3 tenths of the Renishaw, and that's at 140 IPM. Close enough for me.
     
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  29. middle.road

    middle.road Active User Active Member

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    OK, need an opinion here.
    Should I go with something like this on the mill or look for a glass scale solution?
    Is there a chance in hades that this 9-pin would work with my old Mitu Digimatic Display Head or are the signals totally different?
    I'm still leaning towards doing TouchDRO, just trying to get by on a tight budget right now.

    Now for the Kicker - Step Son is in China for a couple of days next week, Bejing. hmmm, wonder if he'd like to do some shopping for a DRO. :)
     
  30. JimDawson

    JimDawson Global Moderator Staff Member Director

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    I can just about guarantee that the pinouts would be different, so a bit of rewiring night be needed. You just couldn't get that lucky.;)

    The other issue might be the output of the read head. I depends on what signal the Mitu wants to see. It could be single ended, or push/pull quadrature, or it could want a 1v P/P sinewave. All of those outputs are available from Ditron. You are going to have to figure out what the Mitu wants. Also you will need the resolution that the Mitu will accept.

    Overall I'm a real fan of mag scales. Easy install, maintenance free, bullet proof, and very compact.

    EDIT: It looks like the Mitu uses a Gray Code encoder. That is basically a serial data comm system. Nothing from Ditron is going to work.
     
    Last edited: Apr 6, 2017
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