Using the 22-805 Multimeter With Linux
To use the Radio Shack 22-805 Multimeter with Linux, a simple application
called multimeter can be used.
Download the source from
here (version 0.0.5) or from the creator's
page at http://www.home.pages.at/linux/.
Unzip and unpack the source, then make it. To run:
multimeter -6 [-l] [-i interface] [-h]
The -6 flag makes multimeter communicate at 600 baud, which is
required for the 22-805. The -l flag instructs multimeter to loop
forever. The -i interface flag will specify which serial port to
use, where interface is /dev/ttySX, where X is the number
correlating to the desired serial port. Multimeter uses serial port 2
(/dev/ttyS1) by default - if that is the port you are using,
you won't need to use this flag. The -h flag brings up a help
screen which has additional flags that can be used.
The highest rate the 22-805 seems capable of communicating (at least
with the multimeter software) is at one transmission per second.
If you wish to write your own code for the 22-805 instead, you'll
need the following information relating to the 22-805 (copied from
its instruction manual):
Transmission rate: 600 baud
Character coding: 7-bit ASCII
Stop Bits: 2
The data format consists of a frame of 14 bytes. The frames are set as follows:
BYTE) 1 2 3 4 5 6 7 8 9 A B C D E
Example 1) D C - 3 9 9 . 9 m V CR
Example 2) O H 3 9 . 9 9 M o h m CR
$Id: multimeter_instructions.html,v 1.1 2002/02/07 00:03:00 duncan Exp $