Single Phase Load Monitoring Relay. Carlo Gavazzi DUB01 ; PUB01 series of monitoring relays provide the user with a precise TRMS AC/DC over ; under voltage monitoring options controlled by DIP switches. LED indication of status changes make simple recognition. TRMS AC/DC over ; under voltage monitoring relay solution DIP switch selection LED indication for relay, alarm and power supply ON SPDT contact configuration Suitable for DIN mounting