So, after finishing up the low-pass filter for the current sensor, I turned my attention back to the BMS-to-MCU-to-Inverter Comms. I was making some great progress on getting the 'dialog' between the MCU and the Inverter ironed out. I coded in the CheckSum calculation, so that is happening automatically now. That made fiddling with the actual information being sent a lot easier. After playing around with the variables in the 'Charge/Discharge Management' response, I was realizing that the inverter was not behaving as I was expecting. Most notably, when I sent the 'disable' command for charging or discharging, the inverter didn't seem to do anything different. And that's where I hit my latest roadblock...
A few of the forum threads related to PylonTech batteries communicating with Growatt/MPP inverters suggested that an inverter Firmware update is often required to get things to communicate correctly. So, using the info and software provided on the Watts247 website, I attempted to update the firmware on my 'test' inverter. That's where things turned south... The firmware update didn't complete, and the inverter stopped turning on. I tried everything I could think of (different PC, different cable, different firmware version) to no avail. Finally had to ask Ian at Watt247 to send me a fresh CPU board, which should be on the way shortly (thanks Ian!).
So, I'll try to pick this back up once I have the new board installed.