I'm having trouble connecting Schneider Electric PowerLogic Meters and DIRIS A20 Power meters over 485 network. I'm using unique addresses to read holding registers and 120 ohm termination resistor. It works but sometimes it goes into 999 (error) state and comes back eventually with correct values. Would this be due to incorrect terminating resistor or due to mixing different hardware (2 types of meters connected in single daisy chain), or would this be due to baud rate (9.6k)? I don't have any more ideas. Please help me if you experienced similar issues. Many thanks.