Detcon 12B - Manual (Page 7)

Model 12B
12B Control Module Instruction Manual Rev. 1.4 Page 3 of 12
CO-12B CO carbon monoxide 0 - 100 ppm 0 - 100
SO-12B SO2 sulfur dioxide 0 - 100 ppm 0 - 200
NO-12B NO2 nitrogen dioxide 0 - 100 ppm 0 – 500
CL-12B CL2 chlorine 0 - 10.0 ppm 0 – 999
CD-12B CLO2 chlorine dioxide 0 - 10.0 ppm
H2-12B H2 hydrogen 0 - 100 ppm
NX-12B NO nitric oxide 0 - 100 ppm
4.0 Alarm functions and settings
Model 12B control modules incorporate several user selectable alarm programming options that are
accomplished via rotary dip switches or jumper tabs. These options include setting alarm points, latching of
relays, contact outputs, energized/de-energized, and firing direction. See figure X for the applicable rotary
switch and jumper tab locations.
4.1 Alarm set points
Three alarms — alarm 1, alarm 2, and alarm 3 — can be set to fire in 1 digit increments via rotary dip
switches. Each alarm features three rotary switches in which the desired alarm level is dialed by use of a
jeweler’s screwdriver: one for 1’s, one for 10’s, and one for 100’s. The switch for 1’s is used to select the set
point of the least significant digit - 0 through 9. The switch for 10’s is used to select the set point of the middle
digit — 00 through 90. The switch for 100’s is used to select the set point of the most significant digit — 000
through 900.
An alarm condition will cause the alarm relay to actuate upon reaching and/or exceeding the alarm set point.
To set an alarm, follow this example: if you want the alarm to actuate at 25 ppm/% you would set the 100’s
switch to 0, the 10’s switch to 2 and the 1’s switch to 5. The chart below shows which switches correspond to
each alarm.
Digits Alarm 1 Alarm 2 Alarm 3
1’s SW2 SW5 SW8
10’s SW3 SW6 SW9
100’s SW4 SW7 SW10
Table 1 Switch positions for setting alarm points