The PSR safety relays from Phoenix contacts can be quickly and reliably assembled to form a tailor-made safety solution.
To connect using TBUS correctly you will need one PSR-TBUS per module. For the last additional module use one PSR-TBUS-TP instead, this will close the feedback loop. The interface module is used for the connection of up to four safety sensors with NC/NO contacts to the safety relay PSR-SDC4, with screw connection.

• Quick system extension up to 10 modules, offering a safety system with up to 42 contacts
• Automatic identification of desired operating mode, no need to set switches or define parameters
• The system is based on a master relay (PSR-SDC) that monitors e-stops, guard doors (interlock or non-contact) and optical devices (e.g. light curtains)
• Safe cross-wiring with T-BUS renders the usual cross-wiring of supply voltage, enable signal and confirmation path redundant. Making commissioning and future expansion simple
• 24Vdc supply voltage
• Semiconductor output
• Depending on the wiring Safety category 2 or 4 can be maintained
• One or Two channel switches are used for control

The device has a rear interface for the DIN Rail connector T-BUS. Via this T-BUS interface extension devices PSR-URM4-B (undelayed contacts) and PSR-URD (drop-out delay contacts) can be controlled and monitored over one channel. These in combination form a T-BUS unit, the feedback path must be connected to the final (right hand) extension device (see datasheet for more details) or by using connection plug PSR-TBUS-TP.