RS-485

RS-485 is a balanced transmission standard that the EIA approved in 1983. It covers only the electrical behaviour of drivers and receivers on a multipoint line, so it works as the physical layer under higher-level protocols. It sends data as differential voltage signals. This gives it better noise immunity and longer reach than RS-232, and when fully implemented many devices can share one bus. CSI string inverters such as the CSI-125KTL-GS-E, CSI-125K-T600GL02-U, CSI-185K-T600GL02-U and CSI-66K-T480GL01-UB list RS485 among their communication interfaces, and the CSI 23/28KTL-CT series runs Modbus over RS485. Several inverters can be monitored over one RS-485 daisy chain, and AlsoEnergy installation material also shows RS-485 wired in a daisy chain. The GE kV RSX meter uses two-wire half-duplex point-to-point RS-485 with RX+ tied to TX+ and RX- tied to TX-, and its manual says not to fit terminating resistors.

<!-- review notes

• sentence 4: support check: partial - Multiple inverters over RS-485 daisy chain is stated, but the AlsoEnergy attribution is not in the passages (only a figure caption on RS-485 daisy chain). -->