Spectrex 20/20MU - Mini Flame Detector - Manual (Page 26)

Spectrex Inc. - SharpEye TM ML & MU Flame Detector Manual – TM 767100, Rev. A, April 2005
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4.4.3 Automatic & Manual BIT
Manual Bit
Functions as described in section 4.4.4. In the case of an unsuccessful BIT all
outputs will function as described in section 4.4.4.but the BIT will be automatically
executed every 1 minute. This mode of operation will continue until successful BIT
has been encountered. As a result, the detector will resume its normal operation.
Automatic BIT
The detector automatically performs a BIT every 15 minutes.
A successful BIT does not activate any indicator.
• The FAULT relay remains CLOSED (NORMAL).
• The LED continues to flash (1 Hz) at green.
• The 4-20mA output continues to indicate 4 mA.
An unsuccessful BIT sequence activates the following:
• The FAULT relay is opened.
• 4-20mA output indicates BIT FAULT (2 mA).
• The LED flashes (4 Hz) at yellow.
• BIT procedure will be performed every 1 minute.
4.4.4 Manual BIT only
The BIT is initiated manually by momentarily connecting PIN No. 3 (or yellow wire)
with PIN No. 2 (or black wire). A successful manual BIT activates the following:
• FAULT relay remains CLOSED.
• ALARM relay is activated for 3 sec (only when Function Alarm BIT at YES)
• 4-20 mA OUTPUT current will be 20mA (only when Function Alarm BIT at
YES).
• The LED will illuminate at red for 3 sec.
Unsuccessful BIT activates the following:
• FAULT relay is opened.
• 4-20 mA output indicates BIT FAULT condition (2mA).
• The LED flashes (4 Hz) at yellow.
Note: During a MANUAL BIT, if Function Alarm BIT is in YES position, the
ALARM relay will be activated and the 4-20mA outputs will initiate 20mA.
Therefore, automatic extinguishing systems or any external devices that
should be activated under actual alarm conditions should be disconnected
during BIT.