Re: DMM with PC interface com protocol

[Kim Wall <kim@xxxxxxxxxxxxxxxxxx>]

Just to add to this thread:

I've invested in one of these multimeters, and I've just poked around
with a serial port sniffer, and it seems that the communication protocol
between the meter and the software is trivial:

The software opens the serial port at 600 baud, with 7 data bits, 2 stop
bits, no parity.  DTR is set, and RTS is cleared (I suspect it uses
these lines to power the interface or something, as no handshaking seems
to be going on).  To take a reading, the software then sends a single
'D' character, and the meter replies with a human-readable string giving
the mode, value and unit, such as "DC  0.000  V",  "OH 
3.772MOhm" and
so on.  This is repeated ad infinitum.

So yeah, easy.  A linux program to read the values into a database is on
my todo list for next week, but I thought I'd post my findings now in
case anyone else wants to write their own software for the thing.

FWIW, the software runs fine for me on my XP Pro/SP2 box, and seems
quite usable for general purpose data logging type stuff.

Interface aside, it's not a bad multimeter for 20 quid.  Reasonably
solid, backlit display, audible continuity, protective yellow holster
and pretentious plastic case.  Does exactly what it says on the tin.


Kim.