I recently purchased a Mitutuyo Digimatic device for making in-process, inspection measurements of product during the manufacture process. Okay, what the heck does DIGIMATIC mean? DIGIMATIC is a Mitutuyo offering that basically offers a cord connecting to some of their devices (i.e. digital caliper) and transmits that measured value serially into a PC.

So, I grabbed my shiny new digital caliper and started measuring random desk fodder. I opened HyperTerminal and this all works GREAT.

The REAL fun begins when you try to connect it to a PLC. Mitutuyo's tech support, although kind and generally helpful, can't spell PLC. Naturally, they're not the best source of assistance.

After 2-3 days of struggling, I discovered that the Mitutuyo Digimatic Device needs 5VDC on Pin 7. Of course to complete the circuit, the 0VDC terminal of the power supply can be connected to Pin 5.

I know this may be a rare case where someone is trying to accomplish this same thing, but hey... what the heck... I thought it might be worth a post.

Feel free to contact me for more info/dwgs/etc., cdacamara [at] ceradyne.com

 

Digimatic means it is digital and electronic as far as I can tell. I haven't done the Digimatic protocol but I am currently working on a converter for the low cost Chinese calipers available everywhere. If you can find one with traceable accuracy or whatever certification you may need, It would probably do the trick. There are converters for these Chinese calipers and scales available already but they are spendy for home use. Probably low cost for business use. Google Yadro for one. Mine won't be done for a little while yet. But when it is, it should be easy enough to use for a PLC because all I intend to do is send the raw data over on am RS232 port ao all you would need to do is send 1 byte and read 3 or 4. Cost should be less than $50. It's an Open Hardware project and the software will be OSS so you can do anything you want.

Regards
cww