I've been playing with an InsightHome Inverter Hub from Schinder Electric. It has a Modbus RTU interface which I have connected with using an RS485 to USB dongle, the results have always been timeouts. My assumption is that the device is actually the Master/Client of the Modbus system and is not compatible as a Slave/Server.
Going another route, I've created a Modbus Slave/Server using the 502 (SunSpec) standard. I validated all the registers with the pysunspec2 package. During the device detection my device is found, there are no errors, but there is no further registration process and my device doesn't appear. Checking the Network Log, the hub replies that the device "Type" as "unknown" and a "isDead" attribute is "N/a"
Here are commands the Hub runs during the Discovery process, in order:
| Command | Addr | Size | Schema |
|---|---|---|---|
| READ_HOLD | 1 | 1 | 503 |
| READ_HOLD | 1 | 10 | 503 |
| READ_HOLD | 40020 | 16 | 502 |
| READ_HOLD | 11 | 1 | 503 |
| READ_HOLD | 40020 | 16 | 502 |
| READ_HOLD | 40020 | 16 | 502 |
| READ_INPUT | 4999 | 1 | ? |
| READ_INPUT | 4999 | 1 | ? |
| READ_INPUT | 4999 | 1 | ? |
| READ_HOLD | 40020 | 16 | 502 |
| READ_HOLD | 49 | 10 | ? |
| READ_HOLD | 49 | 10 | ? |
| READ_HOLD | 49 | 10 | ? |
| READ_HOLD | 49 | 10 | ? |
| READ_HOLD | 3085 | 1 | ? |
| READ_HOLD | 32001 | 1 | ? |
| READ_HOLD | 1014 | 1 | ? |
| READ_INPUT | 42 | 3 | ? |
| READ_INPUT | 1 | 10 | 503 |
| READ_INPUT | 1 | 10 | 503 |
Looking at the known mappings, it's checking for Device/Model names and, I presume, checking it against an internal list of supported devices. Which.. is a shame!
Note: As a debugging process I cross referenced all these requests with my Schinder devices to make sure my Slave/Server is responding the same to each.
This entire process has been nonsensical. I wanted to share as I haven't found a similar attempt online. I'd recommend to stick to Modbus TCP, if you are working with these.
NOTE(neal@2026-08-09): I have had more experiences with solar inverters in the past year and this was the real "issue" I ran into with Schinder's Inverters. They did a wonderful job with this product and I enjoyed working with them. These inverters do not seem to be as popular as they once were, due to being undersized for today's market and built as a modular system. I hope they release a higher kW "all-in-one" version with similar software capabilities.