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Rev. 11-5 12/15/2020
Copyright © 2020 by Cool Air Incorporated. All rights reserved.
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Each relay has a surface-mounted LED associated with it that
indicates the status of the relay. A relay is energized (a non-alarm
condition) when its LED is lighted (green), and de-energized (an
alarm condition) when the LED is not lighted.
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Contacts for external connections:
•
4–20 mA outputs for ammonia level
•
Auxiliary Relay contacts
•
External temperature sensor input
•
Alarm Relay contacts (Hi Alarm)
•
Pre-alarm Relay contacts (Low alarm)
•
LBW-420/-2 AC Power
•
LBW-420-1 DC Power
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The detector has a 4-20 mA analog output that allows it to
communicate with external devices such as computers, PLCs, and
digital displays. The output conforms to ISA S50.01 ratings, Type
2L and Type 2H (two-wire).
The ammonia level detector output current
(TB2, “Sensor 4-
20mA” terminals on lower left of Enclosure Mounted Circuit
Board) is proportional to ammonia PPM with the proportionality
constant dependent on the range. The PPM value can be
determined using one of the following formulas:
PPM = 62.5 (I – 4)
0 to 1000 PPM Range
PPM = 50 (I – 4)
0 to 800 PPM Range
PPM = 31.25 (I – 4)
0 to 500 PPM Range
PPM = 25 (I – 4)
0 to 1000 PPM Range
PPM = 15.67 (I – 4)
0 to 250 PPM Range
PPM = 6.25 (I – 4)
0 to 100 PPM Range
Where PPM equals ammonia concentration in parts per million and
I equal the output current in mA.