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DRO issue "HEDs in hand"
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Ken Jenkins
I posted a message a few days ago regarding the U.S. Digial Linear
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strip options ... 360 is the highest and in my opinion not high enough (360 x 4 = 1440 then 1 / 1440 = .00069 per increment. I want something closer to .0005 which would need 500 lpi. U.S. Digital in a recent email response did not sound very hopeful re: a linear strip with 500 lpi res. So that leaves a rotary encoder and wire arrangement. One would think you would want the highest res possible ... 2048? I have done several postings here in the past and recently ... other than Bubba (who has been very helpful) no one seems to have much information regarding what encoder works well with the Camtronics board. Has anyone used the 360 US Digital strips with the Camtronics board and got it to work and been satisfied with the result? OR Has anyone used a rotary encoder with wire loop arrangement with the Camtronics board and got it to work and been satisfied with the results? Could you share your experience here. Also, you should be aware that just having a couple HEDS does not help you unless they are matched to the particular encoder you select. The HEDS unit and the encoders are selected together and will not work if used with out matching them. There are linear HEDS and rotary HEDS and within those two groups there are specific ones for each resolution. Ken Message: 4 |
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I have used the linear 360 line encoder strips from USdigital with good
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results. I guess you have to ask your self this question. Can my machine really machine to .00069"? The reason I say this is many machines like mill drills and other imported machines suffer from a variety or problems mainly caused by a lack or rigidity of the column and or excessive play in the spindle assembly. If you machine is rigid then the USditial encoders used with the Kulaga/Mauch dro board should be adequate. It should be equal or better than a rotary encoder driven by a rack or cable. I have been following Usdigital's 500 line encoder development for the past three years. I have given up on them solving their problems with it. But that sure would have been nice. Dan -----Original Message-----
From: Ken Jenkins [mailto:kjenkins@...] Sent: Tuesday, October 29, 2002 11:59 AM To: CAD_CAM_EDM_DRO@... Subject: [CAD_CAM_EDM_DRO] Re: DRO issue "HEDs in hand" I posted a message a few days ago regarding the U.S. Digial Linear strip options ... 360 is the highest and in my opinion not high enough (360 x 4 = 1440 then 1 / 1440 = .00069 per increment. I want something closer to .0005 which would need 500 lpi. U.S. Digital in a recent email response did not sound very hopeful re: a linear strip with 500 lpi res. So that leaves a rotary encoder and wire arrangement. One would think you would want the highest res possible ... 2048? I have done several postings here in the past and recently ... other than Bubba (who has been very helpful) no one seems to have much information regarding what encoder works well with the Camtronics board. Has anyone used the 360 US Digital strips with the Camtronics board and got it to work and been satisfied with the result? OR Has anyone used a rotary encoder with wire loop arrangement with the Camtronics board and got it to work and been satisfied with the results? Could you share your experience here. Also, you should be aware that just having a couple HEDS does not help you unless they are matched to the particular encoder you select. The HEDS unit and the encoders are selected together and will not work if used with out matching them. There are linear HEDS and rotary HEDS and within those two groups there are specific ones for each resolution. Ken Message: 4 Addresses: FAQ: FILES: Post Messages: CAD_CAM_EDM_DRO@... Subscribe: CAD_CAM_EDM_DRO-subscribe@... Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@... List owner: CAD_CAM_EDM_DRO-owner@..., wanliker@... Moderator: jmelson@... timg@... [Moderator] URL to this group: OFF Topic POSTS: General Machining If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill List Mom List Owner Your use of Yahoo! Groups is subject to |
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Roger Linscheid
Thanks for the info, I think I'm going to give it a try. I feel that
the resolution should be adaquate for the majority of the work that I do. Dan, how did you mount the strip? I was thinking about a fiberglass plane to support the strip. Hopefully this would lessen the effects of temperature on the system, but perhaps this isn't needed. I remember a website with pics of a linear encoder installation but I guess I didn't bookmark it. Does anyone have a URL showing this setup? Thanks again, Roger Linscheid --- In CAD_CAM_EDM_DRO@y..., "Dan Mauch" <dmauch@s...> wrote: I have used the linear 360 line encoder strips from USdigital withgood results. I guess you have to ask your self this question. Can mymachine really machine to .00069"? The reason I say this is many machineslike mill drills and other imported machines suffer from a variety orthen the USditial encoders used with the Kulaga/Mauch dro board should beby a rack or cable.the past three years. I have given up on them solving their problemswith it. But that sure would have been nice.the drivecurrent thought on the best method to accomplish my goal? installation.cable slipped or stretched. reach it if you have trouble.be a sister site to the CCED group, as many of the same members arethere, for OT subjects, that are not allowed on the CCED list.THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ |
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j_e_f_f_williams
Hello,
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I am using linear strips/encoders from www.encodertech.com. The encoder and strips are about the same price as the US Digital stuff and comes in a 0.01mm resolution which is about 0.0004". The module is a LM-25CPMM-3T and you can get 600mm length strips. The scales are $49.00 and modules $39.00 (almost a year ago). You can order right from them and they are in Fallbrook CA. I have no connection to them other than I used their product on my lathe. I am in Canada and am used to working in mm so the .01mm accuracy worked out well for me. TTYL, Jeff --- In CAD_CAM_EDM_DRO@y..., Ken Jenkins <kjenkins@b...> wrote:
I posted a message a few days ago regarding the U.S. Digial Linear |
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John A. McFadden
Roger:
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The strip has to be seperated from any support by a fraction of an inch (1/4" I think), as the encoder surrounds the strip on three sides (as it uses light passed through the strip to read the lines). John [snip] Dan, how did you mount the strip? I was thinking about a fiberglass |
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is the url for the
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linear encoders. I don't think it showed how I mounted the mylar strip in the 1X2 rectangular tubing. Bascially, I used double sided 3 mil tape cut down to 1/4" wide which was used to stick the mylar strip to a piece of 1/4" aluminum square stock that was installed into the housing. The slider machine to allow for the square stock. Dan -----Original Message-----
From: Roger Linscheid [mailto:r.linscheid@...] Sent: Tuesday, October 29, 2002 7:48 PM To: CAD_CAM_EDM_DRO@... Subject: [CAD_CAM_EDM_DRO] Re: DRO issue "HEDs in hand" Thanks for the info, I think I'm going to give it a try. I feel that the resolution should be adaquate for the majority of the work that I do. Dan, how did you mount the strip? I was thinking about a fiberglass plane to support the strip. Hopefully this would lessen the effects of temperature on the system, but perhaps this isn't needed. I remember a website with pics of a linear encoder installation but I guess I didn't bookmark it. Does anyone have a URL showing this setup? |
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j_e_f_f_williams
Hello,
I was told the same thing. It's actually the 12.5CPMM scales I have but the 25CPMM modules somehow double the resolution?! I eventually had to specifically ask for the scales that matches the 25CPMM modules. Jeff --- In CAD_CAM_EDM_DRO@y..., "John A. McFadden" <mcfadden@c...> wrote: As of 10/11, Encodertech did not have any 720CPI strips in stock inlengths above 3.25", that might have changed, I did not ask. I'll look into it. |
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j_e_f_f_williams
OUCH, $85.00 each for the scales?? Guess I might not get more from
them..... Here is the text from them when I ordered back in January: They are 12.5 Cycles Per mm scales that you could piece end to end. They produce 25CPMM when used with the Module. The price for the scale is $49.00 each. The Module model # would be LM-25CPMM-3T. We do not have Distributors in Canada as yet. You may order directly from the factory here in Fallbrook CA. We accept Visa and MC. The 12.5 [scales] are CPMM (Cycles Per Millimeter). When used with the LM-25CPMM-3T Modules, which doubles the scale resolution, they will produce 25 cycles per mm in quadrature or 0.01 mm resolution after x4 edge detection I wonder why the huge increase in the scale price. Jeff --- In CAD_CAM_EDM_DRO@y..., "John A. McFadden" <mcfadden@c...> wrote: Fast response time on Encodertech's part (like within 3 minutes of myuntil someone pays for the master to be made ($1200) and then only thelength that customer pays for will be made. The price of the LM25cpmm-3S Module is |
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John A. McFadden
As of 10/11, Encodertech did not have any 720CPI strips in stock in lengths
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above 3.25", that might have changed, I did not ask. I'll look into it. John Hello, |
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John A. McFadden
Fast response time on Encodertech's part (like within 3 minutes of my
query), there wont be any 720CPI scales in lengths longer than 3.25" until someone pays for the master to be made ($1200) and then only the length that customer pays for will be made. The price of the LM25cpmm-3S Module is $39.00 each, the price of the 25cpmm-600 mm Scale is $85.00 each. John |
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John A. McFadden
Jeff:
Its $85 for 600mm, $50 for 166-200mm lengths (asked about that length range for my Y and Z axis). Its a good thing you mentioned EncoderTech, I never did the math on the metric scales, and only looked at the 720CPI scales but took them off my list of possibles when they said that they did not have any longer than 3.25". With .0004" resolution and Don Mauch's method for protecting the strips, it looks like I am good to go. I am also a little confused by the math, the US Digital encoders and strips can only quadrature out, giving the resolution as four times the lines per inch of the scales, but Encoder Tech's encoders double the resolution and then quadrature it? Seems a little strange to me, but if it works, it works. What are you using to read the output of the encoder? Are you getting .01mm resolution? John |
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j_e_f_f_williams
Hello,
The scales I have here are 600mm length that I bought for $49 so something changed price-wise. The way I understand it, the 25CPMM module actually has 2 light sources in it that are perfectly offset so as to double the resolution of the scale it is reading. The 2 light sources then send the signal out and that's what you can then quadrature. I am using the parallel port based DRO HW/SW from Art Eckstein. I have it running on a notebook. I have just got a spare desktop machine and monitor for in by the lathe so I will probably get one of Dan's cards soon. I do get 0.01mm resolution and have confirmed the measurments with both actual items turned and the dials on the lathe. TTYL, Jeff --- In CAD_CAM_EDM_DRO@y..., "John A. McFadden" <mcfadden@c...> wrote: Jeff:length range for my Y and Z axis).the metric scales, and only looked at the 720CPI scales but took themoff my list of possibles when they said that they did not have any longerthan 3.25". With .0004" resolution and Don Mauch's method forprotecting the strips, it looks like I am good to go.and strips can only quadrature out, giving the resolution as four times thelines per inch of the scales, but Encoder Tech's encoders double theresolution and then quadrature it? Seems a little strange to me, but if it works,it works. What are you using to read the output of the encoder? Areyou getting .01mm resolution? |
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