Queries and logs information for MRD - Earth Leakage Devices using RS-485 serial to USB interface
This converter was used but any RS-485 to USB converter should work.
As this converter is full duplex and the ELD operates on half duplex the connection should be wired as below, with additional ELDs daisy chained rather star connected. If the connection is over a longer distance consider using twisted pair cable.
If everything has previously been set up, simply connect the ELD and run
python3 log.py
Create a python 3 virtual environment
python3 -m venv mrd-eld
Activate the virtual environment
source mrd-eld/bin/activate
Install required packages
pip3 install requirements.txt
Make sure serial folder is owned by user
sudo chmod 666 /dev/ttyUSB0
Run logger
python3 log.py
By default logs are stored to Log{current timestamp}.csv
usage: log.py [-h] [--port PORT] [--noterminal] [--nolog] [--file FILE]
[--id ID] [--poll POLL] [--edit_id EDIT_ID]
Communicate with MRD - Earth Leakage Device.
optional arguments:
-h, --help show this help message and exit
--port PORT Manually set port, default is /dev/ttyUSB0
--noterminal Flag to stop terminal output
--nolog Flag to stop logging to file
--file FILE File to log queries to, default is current
"date_time.csv"
--id ID ID(s) of ELD to address default is 01. Comma seperate
for multiple ELDs e.g. 01,02
--poll POLL Polls the ELD every n seconds, default is 1
--edit_id EDIT_ID Changes the ID of the ELD currently connected must be
between 1 and 98 inclusive. Only use while connected to
single ELD. Exits after completion.
The main library used for serial communcations in this implementation is pyserial. More information can be found here