The serial communication timing parameters during probe get determined
from earlier serial port configuration, which obsoletes the redundant
'baudrate' parameter, and eliminates potential inconsistency between
user specified parameters and builtin default values.
Default to the existing "P1" etc naming scheme for analog channels of
serial-dmm subdrivers. Add support for subdriver specific channel names
(which can reference the channel number if they desire). This is useful
for devices with multiple displays, or special purpose devices where
other names than P1 can better reflect the channel's nature.
Optionally create multiple analog channels in serial-dmm's scan()
routine. Allow the meters' parse routines to fill in more than one
analog value from the inspection of a single packet.
Use "large" (4 times 14 bytes) packets for the Metex M-3860M and the
PeakTech 4390A meters, and have those large packets parsed by wrapping
the routines for regular 14-byte Metex packets, and sending four values
to the session bus after reception of one large packet.
Thanks to Frank Stettner <frank-stettner@gmx.net> for testing and
fixing the initial implementation of this extension.
The Brymen BM25x series supports the BC-20X that is an opto-isolated
serial cable. The link seems to be unidirectional i.e. when activated
the DMM periodically sends updates to the host while the host cannot
control the DMM in any way.
The protocol is documented in "6000-count-digital-multimeters-r1.pdf"
that is available from the manufacturer. Every 15 byte packet consists
of a bitmap where the bits correspond to segments or symbols on the
LCD display i.e. the DMM essentially sends the contents of its screen
to the host in every update. This driver then decodes the measured
quantity, unit and its value from the bitmap.
Gerhard Sittig
Uwe Hermann
Lars-Peter Clausen
Martin Ling
Baruch Even
Janne Huttunen
Bert Vermeulen