Dynamic DX2-REM550 - Page 39

GBK60348: Issue 3 39
Fail-safe Operation 2.7.2.2
The fail-safe operation option provides additional protection against faults including
disconnected jack sockets (open circuit) and damaged switch circuit cables that
result in the UCI connections being either open circuit or short-circuit.
Failsafe UCI circuits are based on the following circuit. Note that either switch may be
omitted if not required.
When operating in fail-safe mode the UCI inputs detect the following resistance
bands.
Event
Nominal
Resistance
(Ω)
Acceptable
Resistance Band (Ω)
Fault
Short Circuit
< 40
S1 and S2 closed
75
40-100
S2 closed
225
170 - 270
S1 closed
375
330 - 412
No switches closed
525
480 - 575
Fault - Cable broken or plug disconnected
Open Circuit
>575