905U-L Wireless I/O Installation Manual
905U-L Wireless I/O
Page 24 of 40
Version 1.9
Relay outputs
The 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, ELPRO 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.
AC
Load
Max 250VAC 1A
10nF
250V
DC
Load
Max 30VDC
1A
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
IMPORTANT SAFETY INFORMATION
