Spectrex 20/20R - Single IR Flame Detector - Manual (Page 23)

Spectrex Inc. - SharpEye TM Single IR Flame Detector Manual – TM 20/20R, Rev. A January2005
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B. Principles
If the result of a BIT is the same as the detector’s current status (NORMAL or
FAULT), the detector's status will not change.
If the result of a BIT differs from the detector’s current status, then a second BIT is
executed after a delay of 0.5 seconds.
If the result of the second BIT is the same as the previous BIT (and still differs
from the current status), the detectors’ status will be changed. (From NORMAL to
FAULT or from FAULT to NORMAL).
Note : When in FAULT status the detector disables its outputs.
C. Manual BIT only (SW1-3 = OFF)
The BIT is initiated manually by momentarily connecting Terminal No. 3 with
Terminal No. 2.
Successful manual BIT activates the following:
• FAULT relay is closed.(normal)
• ALARM relay is activated for 3 sec (SW1-4 = ON)
• ACCESSORY relay is activated for 3 sec (SW1-5 = ON)
• 4-20mA OUTPUT current will be 15mA when SW1-4 = ON
or 10mA when SW1-5 = ON & SW1-4 = OFF.
Unsuccessful BIT activates the following:
• FAULT relay is released. (Operated)
• 4-20mA output indicates FAULT condition (0mA).
• POWER LED (yellow) flashes (4 Hz).
Important Note!
If SW1 switches 4 or 5 are in their "ON" position, the ALARM and ACCESSORY
relays will be activated during a MANUAL BIT, therefore, automatic extinguishing
systems or any external devices, that should not be activated during BIT, should
be disconnected.