Looking to communicate with a Grundfoss RSI pump controller without having to buy the $300 CIU Modbus interface card. Searches indicate that a few folks have done similar things in the past couple years, specifically @dwarning and @qballza . Looks like I'll need to combine the info from your work, with the CRC table and the command list and whatever else you have. Maybe a POC from India that can pass along the software you used to sniff the serial communication?
I'll be using ESP8266 modules (using Tasmota firware, so Arduino core) which has serial drivers available. Not sure about the CRC calcs though.
Any help is appreciated.