Package: driver2200087
This is a Python Package to interface with Radio Shack’s 2200087 Multimeter.The 2200087 is an inexpensive DMM which supports logging and graphing data on
a computer, but the supplied code only supports Windows. This is a python package
to allow for connecting to the multimeter over USB on Linux or Mac OSX. Due to
radioshack not supplying any serial specifications, the protocol was reverse
engineered by David Dworken from simply observing the output of the DMM.TheserialDecodermodule and the serial protocol documentation is essentially a
slightly tweaked version of the script written and maintained by David Dworken,
available athttps://github.com/ddworken/2200087-Serial-Protocol.gitThis package includes a version of theserialDecodermodule, slightly refactored
to allow it to be imported into other python scripts. It also includes arunnermodule which contains a Twisted protocol, wrapped by Crochet. This module should
be relatively easier to include into other python scripts and applications.InstallationThis package has been tested only with python 2.7.This package can be installed from pypi using pip:$ pip install driver2200087Or using easy_install (python 2.7 only):$ easy_install driver2200087UsageStandalone usage is listedin the documentation,
and should be fairly straightforward to follow.TheserialDecodermodule can also be imported and used from within a python script,
and thedocumentationcan help you use it in that manner.The recommended way for using the package, though, is through therunnermodule which
it provides. The simpler form of use is to get the latest available value whenever
necessary. A short example of how this can be done using this package in a typical python
application would befrom driver2200087 import runner

dmm = runner.InstInterface2200087()
dmm.connect()

# Other Application code
# ...
#
# And when the measurement is required :

if dmm.data_available() > 0:
    print dmm.latest_point()
else:
    raise Exception # Or pass, or retry, as per application requirements

# other application code
# ...If the application calls for continuous recording of the data, the following is likely a
better approachfrom driver2200087 import runner

dmm = runner.InstInterface2200087()
dmm.connect()
while True:
    if dmm.data_available() > 0:
        print dmm.next_point()Note that in this code snippet, the python interpreter is blocked by the
infinite while loop. This is not required by the module. As long as
dmm.next_point() is called often enough (10 Hz), you can use whatever mechanism
you like to actually make the call. Note that dmm.data_available()mustbe
checked by your application before making the call, or you should trap the
exception that results.Making the call at less than this frequency will cause data points to be lost
when the point buffer fills up - if your application only calls for the
occasional measurement, you’re probably better off with dmm.latest_point()
instead.For an example of using therunnermodule from within a larger framework
by subclassing the provided twisted protocol, seethe corresponding Tendril module.
TheTendrilmodule, while WIP, also includes examples of parsing the obtained
datapoint strings into usable values.Downloads and DocumentationThe simplest way to obtain the source for this package is to clone the git repository:git clone https://github.com/chintal/driver2200087.git driver2200087You can install it as usual, with:python setup.py installThe latest version of the documentation can be found atReadTheDocs.Licensedriver2200087 is distributed under the GPLv2 license.