Ian,
Don’t understand your problems with the YADRO site – it just opened OK fpr me.
The following site also has useful data on operation of Chinese scales. I have used modified digital calipers on my lathe and mill for several years now, and built an interface to an old obsolete laptop using this data. Bit of simple programming with QBasic, and I had my display. Incidentally, the site calls itself Shumatech support, but the scales I have are not Shumatech. They are, however, apparently identical to the ones on the site – certainly they are the same electronically. Two of the units I have appear to be slightly different to the others I have, in that the digital display is physically bigger and easier to read – but still electronically the same. Note the warning on the site about MItutoyo scales.
Also a word of warning about these scales. Soon after fitting mine, I began to experience erratic readings (on the mill) the reading would change with no warning, or would flash on and off. I eventually traced this to particles of metal which had worked their way under the sliding portion of the scale. I believe these scales operate on a capacitive principal, and the metal was obviously affecting this. I initially tried shielding the scale with a piece of clear plastic, but this is difficult to do completely effectively, since one part of the scale is fixed, and the other moving. Eventually I relocated the scales on the machine so they were less affected by stray swarf (dust size particles are enough to affect it), but then I couldn’t read the scales easily, so I built the laptop interface. As far as I can see, the newer scales intended for machine mounting are exactly the same as the digital caliper type, so I believe the problem may still exist.
I also tried gluing pieces of felt under the edge of the moving part, similar to the wipers fitted to the ways of some machines, in an effort to prevent the problem – this works, but after a time, the felt inevitably wears, or comes unstuck, and I was back where I started.
Now I just clean them out periodically (pain!), and its a bigger pain when it happens in the middle of a job.
Also I understand that Little Machine Shop (use google) can supply suitable interface cables for these chinese scales – I just soldered a 4 core screened cable to mine.