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Cheap linear scale display

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DerryUK30/04/2011 00:25:15
125 forum posts
The large linear scales look as though they have an RS232 connector on the end of their cable. Has anyone connected one to a laptop/desktop and used that as a display?
 
Derry.
Steve Garnett30/04/2011 00:34:58
837 forum posts
27 photos
It may look like the same connector that RS232 uses, but that's a standard 9-pin D-type connector and it can be used for any wiring scheme you like. And that's exactly what the scale manufacturers do.
 
That said, you can use a laptop to read these scales, but you need an adaptor board and some software. Fortunately for you, it's all been done - have a look at this site.
Les Jones 130/04/2011 08:41:18
2292 forum posts
159 photos
Hi Derry,
You say "Large linear scales" but which large linear scales ? I think Steve has given you as much help as possible with the lack of information. The output could be quadrature signals (Either sine waves or square waves.) or could be the manufacturers proprietary standard for example Newall spherosyn.
Les.
Ian S C30/04/2011 13:34:04
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7468 forum posts
230 photos
One of my digital calipers states in the instuction booklet that it may be connected to a computor or remote scale by a suitable connecting cable, not suplied, or available.
Ian S C
jomac30/04/2011 14:37:44
113 forum posts

Ian Hi, two of my calipers have outlets on them similar to the battery charger on my new mobile, ( the wife picked up the wrong trousers and washed them including the mobile) stuffed the battery and all my contacts!!!! the 600mm linear scale and separate read out has an outlet a bit bigger as per my old mobile. Dont know what they are Im'e not a sparky. I got the long linear scale cheap off e/bay, I was the only bidder. $37, cheap??? or wot.

You got to be lucky sometimes

John H

Steve Garnett30/04/2011 16:37:02
837 forum posts
27 photos
Well, if you tell us exactly what sort of calliper it is (manufacturer's name and ideally a model number), we can probably tell you a lot more about its output capability. There aren't that many standards in common use, at the end of the day...
wotsit30/04/2011 17:12:34
188 forum posts
1 photos
Take a look here also
 
 
JasonB30/04/2011 17:22:11
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25215 forum posts
3105 photos
1 articles
The fact the OP asked about RS232 connectors would tend to rule out the calliper type scales and more likely point towards the glass linear scales that the likes of Allendale supply which have this type of plug.
 
Jason
DerryUK30/04/2011 21:07:07
125 forum posts
Well JasonB hit the nail on the head. I have been searching the web and found very little hence my question, 'has anybody done it.'
 
I'll keep noodling as the thought of spending £200 on a display unit when I already have redundant but serviceable laptops and desktops waiting to be put to use bugs me.
 
I have downloaded some software for an old Shumatech unit which I am in the process of disassembling to see what I can glean. Don't hold your breath though this is really a winter job!
 
Thanks for the input.
 
Derry.
John Olsen01/05/2011 01:18:11
1294 forum posts
108 photos
1 articles
There is a brand called Measuremax who use a form of serial interface between the calipers or scales and a small display unit. They sell a lead that fits the tiny plug on the scale unit and has a USB plug on the other end. It likes to fall out. However, I don't think it is USB electrically, I don't think you can just plug it into a PC and run a program to use the PC as a display...which is a pity as that would be a cool idea. They do sell a small unit that does the display as a separate item. I have one of these, it is supposed to run from a phone style rechargeble battery. The battery for mine died, I am trying to come up with a way of running from the mains, but so far have been getting interference type problems, the wires are evidently picking up noise and I haven't been able to find a way to eliminate it. (eg making sure the scale is insulated from the machine itself.)
 
If all this sounds like damning with faint praise, you are on the right track...everything including the scales was much cheaper than the top line stuff, and the accuracy is fine...if I just use the scales everything is great, except that I have to bend around awkwardly to read the scales themselves. The little display would be nice, if I could just set it up to run from the mains. Since they don't always get turned off, battery operated things have a habit of being flat just when you need them.
 
The code used for the signals from the scale to the display are documented in some of the measuremax stuff that can be found online. Of course other brands with similar connections may not use the same code.
 
regards
John
Les Jones 101/05/2011 09:09:04
2292 forum posts
159 photos
Hi Derry,
The Yadro design that Steve Garnett mentioned only supports the original 2 * 24 bit Chinese protocol and BCD directly. It can be used with quadrature scales in conjunction with the QCC100 converter from the "Shumatech" website. I have used the Yadro design on my lathe and it works very well. There are several designs (Including source code.) on the web for displays for the 2 * 24 bit protocol. I assume the "old shumatech unit " you refer to is the DRO350. I now have one of these on my mill and lathe and the also work very well. The PCB's and other components are still available for these. I STILL THINK THE FIRST STEP IS TO IDENTIFY THE SCALES YOU HAVE AND THE PROTOCOL THEY USE. I agree with you on your statement that disassembling the DRO350 code is a winter project.
Les.
Ian S C01/05/2011 12:22:15
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7468 forum posts
230 photos
On my calipers they call it a printer read out port, its on all thre of my calipers. The port is situated at the top right when looking at the read out display, under a sliding cover. there are four 1 mm copper strips, 1 mm apart on a bit of circiut board, and I suspect it's standard on all calipers. There is no indication of what program or code is required.
Ian S C
JasonB01/05/2011 13:06:15
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25215 forum posts
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Ian and others Derry is not talking about caliper type scales, he wants to use glass linea scales with a PC as the readout.
 
J
Les Jones 101/05/2011 14:24:19
2292 forum posts
159 photos
Hi Ian,
Most of the calipers made in China have this data port. Although the electrical signal are the same there are three different protocols in use. Originally they were mostly 2 * 24 bit protocol and a small number of BCD protocol. about two years ago calipers (and scales) using BIN 6 protocol started to appear mostly in the US. These scale now seem to be more common and the 2 * 24 protocol ones are becoming difficult to obtain. If you want to use a remote display for your scales I have URL's for some sites with designs for stand alone displays and PC interfaces for the original 2 * 24 bit protocol. I agree with JasonB that the scales that Derry has will not be any of these three protocols and will most likely be quadrature signals but we will not know for sure unless Derry is prepared to give some more information on them.
Les.
Ian S C01/05/2011 15:10:51
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7468 forum posts
230 photos
Most of the 'glass linea' scales and digital caliper / micrometers from China use one system. I looked at one system Hobbymetrix - Yadro gives a complete kit to build for $189.95 CDN, available in the UK through L. S. Caine Electronic Services, This system will feed into a computor on windows XP does not work on windows 7.
Mitutoyo use a different system.
A bit of a wander around google will find the info. Ian S C
Les Jones 101/05/2011 18:40:27
2292 forum posts
159 photos
Hi Ian,
The Yadro does not work with any version of windows - it only works with dos.
This means that a very old PC is good enough to run the software. It will not work on modern laptops as the do not have a serial port and dos does not recognise the USB so a USB to serial converter cannot be used. I built my Yadro on stripboard as the circuit is so simple.
Les.
DerryUK01/05/2011 23:38:21
125 forum posts
Thanks for the input guys.
 
I don't have any scales at the moment. I am building a motorbike that is a mixture of UNF and Metric fittings. Switching between the two isn't too difficult on my imperial lathe and mill as I usually use a metric/inch vernier caliper (or rule) to measure things.
 
As you stand there machining your mind wanders and you think 'wouldn't it be nice if ...' in my case switchable readout. I had a look in MEW and thought a pair of Newall scales would be nice but can I get anything cheaper...?
 
While looking at glass scales on the net the thought occurred to me re RS232 and D type connectors.
 
<A bit of a wander around google will find the info>
If only Ian ....!!!!!!! I've wandered around so much it feels like I am back in the Colossal Cave (running on an ICL1906S.)
 
Derry.
JasonB02/05/2011 07:58:23
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25215 forum posts
3105 photos
1 articles
Well from the little wandering I have done on the subject it wood seem you need something like the YADRO to get the scale readout onto the screen and a dongle for each scale such as the Scumateck QCC-100 to convert the glass scale Quadrature into the chinese signal that the YADRO accepts.
 
Now whether thats cheaper and less hastle than an off the shelf budget readout is upto you, I went for slimline scales and universal console from Alendale.
 
J
John Olsen02/05/2011 08:02:49
1294 forum posts
108 photos
1 articles
>You are in a maze of twisty little passages, all the same.
 
For the scales, you are in a good position, just do the research before you buy any so that you know what display units are available for them, preferably buy the whole lot at one time from one supplier.
 
Once you have scales on a machine, the question of whether ir not it is metric or imperial ceases to have any meaning, which is great. Except of course for screwcutting!
 
regards
John
 
 
Les Jones 102/05/2011 09:14:07
2292 forum posts
159 photos
Hi Derry,
If you can afford the glass scales i would recommend them over the Chinese scales. I have the original 2 * 24 bit Chinese scales on my mill and lathe. The Bin6 scales you can get now have two disadvantages over the original 2 * 24 bit type. One they auto power down after a time. Two the sample rate is only about seven sample per second compared with 50 times per second for the original type. (When in fast mode.)
My first attempt at a DRO on my mill was quadrature rotary encoders on the leadscrews with a PIC driving an LCD display. The code was based on the QCC100 as the source code is available for that. As you are attempting to disassemble the DRO350 code you should have no problem building a display for glass scales
Les.
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