Hi everyone,
I’m working with a Solis EPM3-5G-Plus device connected to multiple Solis grid-tie inverters via its Comm-INV RS485 port, where it acts as a Modbus RTU master for power curtailement purpose. I also have a server (Revpi) configured as a Modbus RTU master, which I initially tried to connect to the same RS485 bus via the Comm-INV RS485 port.
My goal is to read and write Modbus data from the EPM, and indirectly control and monitor the inverters through it. However, this setup results in timeouts and communication failures, likely due to having two masters on the same RS485 bus (EPM / REVPI server).
I discovered that the EPM has a dedicated RS485 RJ45 port typically used for monitoring (normally via a WiFi/GPRS datalogger). What confuses me is that Solis provides a Modbus register map for the EPM that includes read/write operations, which implies that the EPM can be externally controlled. I’ve successfully tested this by communicating only with the EPM using a RevPi (RevPi as master, EPM as slave) via the Comm-INV port.
My question is:
Can the RS485 RJ45 monitoring port be used to connect an external Modbus RTU master (like the RevPi or any other server) to access EPM data and send commands, so that the EPM functions both as a slave (on the monitoring port) and a master (on the Comm-INV port), assuming no Solis datalogger is connected?
Has anyone achieved this successfully? Are there any specific settings required in the EPM to enable this functionality?
Thanks in advance!