Cooper Bussmann BU-905U-L installation manual Relay Outputs, Important Safety Information

Cooper Bussmann BU-905U-L Wireless I/O Installation Manual

Relay Outputs

The BU-905U-L-R module provides three normally open voltage-free relay contacts rated at 250Vac / 30Vdc 1A.

You can use these outputs to directly control low-powered equipment or power larger relays for higher-powered equipment.

For inductive loads, Cooper Bussmann recommends:

DC relays - use flyback diodes across the external circuit to prevent arcing across the relay contacts.

AC relays – use capacitors (e.g., 10nf 250V) to prevent arcing across the relay contacts.

You can individually configure digital outputs to turn off if no command message is received by the output for a certain period. This feature provides an intelligent watchdog for each output, so communications failure at a transmitting site causes the output to revert to a known state.

The output circuit is connected to the appropriate pair of Digital Output terminals. Each digital output circuit includes a LED indicator that lights when the digital output is active. The LED flashes if the watchdog alarm is active.

IMPORTANT SAFETY INFORMATION

In order to comply with Electrical Safety Standards, when connecting SELV AND voltages which are greater than SELV (30Vac or 60Vdc)

together, then Relay Output 2 must NOT be used in order to provide sufficient isolation between the outputs

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