When using long communication cables (up to 15m for RS-232C), always connect the shield line to the FG (frame ground) terminal to minimize signal noise.
RS-485 or RS-232C interfaces are available for connecting to PLCs or other external devices. yamatake sdc20 user manual
Options include standard PID control, ON/OFF control, and advanced "RationaLOOP PID (Ra-PID)" combined with self-tuning for minimized overshoot. When using long communication cables (up to 15m