Radio Shack has a RS232 DMM (model 22812)which is a pretty decent value for 69$, and can log data using their 'METERVIEW' Windows program. However, there is no documentation on the RS232 data format used, either in the manual or on the CD, that I can see. Hyperterminal snooping seems to show it is using some binary format, and not a simple ASCII text mode. Anyone know how to decipher this data stream format? Would like to use it with other software, e.g. National Instruments etc. tia!
Hi Tia, Here you go: http://support.radioshack.com/support_meters/doc68/68424.pdf The link was kind of hard to find, and I still dont remember how I stumbled across it! Basically, it encodes boolean values of which LCDs are turned on or off and sends them in small frames over the serial port. You need to use bitwise ANDs to see which LCDs are turned on and figure out the numerical value from that. I can send you the source code in Visual Basic if you like, with details about how we read voltage over the serial port through the multimeter. I think I have commented it, so it should be easy to understand. Like you, I needed to have a device (for a University of Florida research project) that could read voltage over a serial port, and the Radioshack one was inexpensive and easy to get! But we were miffed when we found that there was no support documentation for interfacing with the PC. As I said, I still dont remember how I found it, but I finally did, and we got it to work for our project. Funny, I was just searching for the same link again (this time I found it on google by searching for 'site:radioshack.com pc interface') and found your topic, so I felt I should help you out - having gone through the same trouble. Sorry for being so verbiose! I will probably write a tutorial about it sometime on some of the VB forums. Regards, Suman
