RS-422 serial link for GOT HMI
The FX5-422-BD-GOT is a serial communication board that adds an RS-422 port to a Mitsubishi MELSEC iQ-F series PLC, specifically for connecting a GOT HMI. It uses an 8-pin MINI-DIN female connector and communicates half-duplex at baud rates from 9600 to 115200 bps. The maximum transmission distance is defined by the GOT's specification, not by the board itself — so the cable run limit depends on the HMI model at the other end.
No isolation — ground-loop awareness needed
The communication line is not insulated from the CPU module, meaning there is no galvanic isolation between the RS-422 signals and the PLC logic. In an environment with large drives or high common-mode voltage, this can couple noise into the serial link unless the ground reference is shared cleanly.