Emerson Rosemount 975UF Reference Manual page 22

Introduction
June 2021
Table 1-5: Detector Statuses
Status
BIT fault
Fault
In each state, the detector activates different outputs, as specified in
Table 1-6: Output Signals vs. Detector State
Detector state LED indicator
Normal Green
Warning Red
(2)
Alarm Red
(3)
Latch Red
(4)
BIT Fault Yellow
Warning at BIT Red
Fault
Alarm at BIT Red
Fault
Fault Yellow
The auxiliary relay can be activated at the Warning level or Alarm level, depending on programmed function.
(1)
(2) The alarm outputs are activated while alarm conditions exist and will stop approximately five seconds after a fire is no
longer detected.
(3) The Alarm state can be optionally latched via programmed function. (Default is non-latching).
(4) The detector will remain in BIT Fault state until it has passed a successful built-in test.
Note
The outputs depend on the output configurations.
Optional latching
Alarms are set as non-latching by default. However, the detector includes a latched alarm
output capability, which operates according to the programmed function.
If selected, upon detection of a fire, the detection signal is latched until the operator
manually resets the detector by disconnecting the power supply.
Latching affects the alarm relay, 0-20 mA output, and the alarm LED. The auxiliary relay is
latched only when the programmable function Auxiliary Relay is set to Yes.
22
(continued)
Description
A fault is detected during built-in test sequence or other electric
failure. The detector will continue to detect for fire.
A fault is detected when the power supply is too low or due to a
software fault or electrical failure. The detector will not detect fire
in this condition.
LED mode Alarm relay
1 Hz Off
2 Hz Off
Constant On
Constant On
4 Hz Off
2 Hz Off
Constant On
4 Hz Off
Auxiliary relay Fault relay
Off On
(1)
On On
On On
Off On
(1)
On On
Off Off
(1)
On Off
On Off
Off Off
Emerson.com/Rosemount
Reference Manual
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Table 1-6.
mA output
4 mA
16 mA
20 mA
20 mA
20 mA
2 mA
16 mA
20 mA
0 mA