A tool for monitoring a Magnum inverter using Python and a RS485 to serial converter.
Chris (aka user cpfl) Midnightsolar forum. Author: Paul Alting van Geusau Modifications by: Liam O'Brien
After purchasing a Magnum MS4488PAE inverter to use with my off-grid power setup I wanted a way to monitor and control the system without buying the over-priced Magnum Remote for $200. After some digging I found this forum topic that covered logging data using a RaspPi and RS485-Serial adapter. It turns out that the code needed to be modified slightly to work with a remote-less setup without failing. After I fixed that I also added some extra data outputs. The goal is to integrate this data into an EmonCMS install to do long term logging of my PV array and inverter, I will update the code here as I work towards that.
As it would happen the pinout described by Magnum's comm's protocol document was out of date, at least for my inverter. I had to spend an evening probing the output of the RJ-11 jack with a logic analyzer and oscilloscope to find the RS485 lines. Once I did everything worked perfectly.
To save some time on your data-logging journey see the pinout below, this is assuming you go from left to right with the connector tab facing away from you:
Green "Network" port on the MS4488PAE
- 1 = NC
- 2 = (A+ 0-5V)
- 3 = (GND)
- 4 = NC
- 5 = (B- 7-12V)
- 6 = (14V w/respect to 3 as GND)