Spectrex 20/20U (UB) - UV Flame Detector - Manual (Page 21)

Spectrex Inc. - SharpEye™ UV Flame Detector Manual – TM 20/20UB Rev. E, August 2004
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4.4 Detector States
The detector can be in one of the following states:
Normal:
The detector is functioning.
BIT: The detector performs a BIT.
Warning: Fire detected - changes to its Warning pre-alarm state.
Alarm: Fire detected - changes to Alarm state.
Latched Alarm: The alarm outputs are latched after alarm state due to the
detection of a fire even when the fire has already been
extinguished (default is non-latching)
BIT Fault: A fault is detected during BIT sequence. The detector will
continue to detect fire if the alarm conditions occur
Fault: A fault is detected when the power supply is too low or during a
software fault.
In each state the detector will activate different outputs as specified in Table 6.
Table 6. Output Signals Versus Detector State
Detector
State SW1 Yellow
LED Red
LED Alarm
Relay Accessory
Relay Fault
Relay 4-20mA
Output
Fault
2Hz OFF OFF OFF OFF 0mA
BITFault 2Hz OFF OFF OFF OFF 2mA
Normal
0.5HZ OFF OFF OFF ON 4mA
Warning
SW1-4 on 0.5Hz 2Hz OFF ON ON 16mA
Alarm 0.5Hz ON ON * ON 20mA
Latch SW1-1 on 0.5Hz ON ON * ON 20mA
Warning
at BIT
Fault
2Hz 2Hz OFF ON OFF 16mA
Alarm at
BIT Fault 2Hz ON ON * OFF 20mA
* Depends on SW 1 -4 set.
The detector remains in Fault state until it passed a successful BIT. When SW1-4
is OFF, warning state is the same as the Alarm state. The alarm outputs are
activated as long as the alarm conditions are present and stop approximately five
seconds after the fire is no longer detected.