Magnum 2 MQTT

A tool for monitoring a Magnum inverter using Python3 and a RS-485 to serial converter, then publishing that data to an MQTT broker.

Credits

Prior work in this arena from:

Chris (aka user cpfl) Midnightsolar forum.
Paul Alting van Geusau
Liam O'Brien

Backstory

Code from earlier versions of the repostiory based heavily on work by Liam O'Brien and others noted above.

This version is a complete rewrite:

Now uses a protocol definition file and interpreter model.
Changed the Serial data collection to provide better synchronization to the on-the-wire protocol
Moved the Serial collection a separate thread.
Added better 'junk' packet rejection.

Known issues

For the PT-100, the documented mode and regulation ( Accessory segment 0xC1, byte 2 ) does not follow observed data.
ACLD Remote packet ( remote 0xD0 ) is not documented in the spec PDF file I have, thus not provided for in the spec file.

Usage

Copy files from /etc and /usr to system with an RS-485 serial converter.
Reload the systemd daemon:
```
# systemctl daemon-reload
```

Modify options in /etc/default/magpi for MQTT broker and rentention based on command line options:

# ./magpi.v3.py  --help
usage: magpi.v3.py [-h] [-b BROKER] [-d {0,1,2}] [-i INTERVAL] [-p PORT] [-r]
                   [-s SPECFILE] [-t TOPIC]

optional arguments:
  -h, --help            show this help message and exit
  -b BROKER, --broker BROKER
                        MQTT Broker to publish to
  -d {0,1,2}, --debug {0,1,2}
                        debug data
  -i INTERVAL, --interval INTERVAL
                        MQTT update interval ( default 1 second )
  -p PORT, --port PORT  commuications port descriptor, e.g /dev/ttyUSB0 or
                        COM1
  -r, --retain          MQTT Retain?
  -s SPECFILE, --specfile SPECFILE
                        Magnum Protocol Spec File
  -t TOPIC, --topic TOPIC
                        MQTT topic prefix

Enable & Start the service, specifying the proper RS-485 serial device ( e.g. ttyUSB0 )
```
# systemctl enable --now magpi@ttyUSB0
```

Inverter Remote / Network port pinout:

Holding a 6 Pin RJ-11 connector with the tab facing away from you, cable dropping out of that connector toward you, here is the pin-out from left to right:

1 = NC
2 = (A+ 0-5V)
3 = (GND)
4 = NC
5 = (B- 7-12V)
6 = (14V w/respect to 3 as GND)

NOTE: Magnum cautions that Pin 6 voltage should NOT be used to power any accessories.