Detcon IR-642 - Manual (Page 17)

3.9.1 Alarm Levels
Both alarm 1 and alarm 2 levels are factory set prior to shipment. Alarm 1 is set at 20% of full-scale range; alarm 2
at 60% of full-scale range. Both alarms can be set in 0.01% increments from 10 to 90% of full-scale range. The fol-
lowing procedure is used to change alarm set points:
a) First, enter the programming menu by holding the programming magnet stationary over “PGM 2” for 30 sec-
onds until the display reads “VIEW PROG STATUS”, then withdraw the magnet. At this point you can
scroll through the programming menu by momentarily waving the programming magnet over “PGM 1” or
“PGM 2”. The menu options are: View Program Status, Set Alarm 1 Level, Set Alarm 2 Level, and Set Cal
Level.
b) ALARM 1 LEVEL From the programming menu scroll to the alarm 1 level listing. The menu item appears as:
“SET ALARM 1 LEVEL”. Enter the menu by holding the programming magnet stationary over “PGM 1”
for 3 seconds until the display reads
“SET ALM1 @ x.xx%”, then withdraw the magnet. Use the program-
ming magnet to make an adjustment to “PGM 1” to increase or “PGM 2” to decrease the display reading until
the reading is equal to the desired alarm set point. Exit to the programming menu by holding the programming
magnet over “PGM1” for 3 seconds, or automatically return to the programming menu in 30 seconds.
c) ALARM 2 LEVEL From the programming menu scroll to the alarm 2 level listing. The menu item appears as:
“SET ALARM 2 LEVEL”. Enter the menu by holding the programming magnet stationary over “PGM 1”
for 3 seconds until the display reads
“SET ALM2 @ x.xx%”, then withdraw the magnet. Use the program-
ming magnet to make an adjustment to “PGM 1” to increase or “PGM 2” to decrease the display reading until
the reading is equal to the desired alarm set point. Exit to the programming menu by holding the programming
magnet over “PGM1” for 3 seconds, or automatically return to the programming menu in 30 seconds.
d) Exit back to normal operations by holding the programming magnet over “PGM 2” for 3 seconds, or automati-
cally return to normal operation in 30 seconds.
3.9.2 Alarm Reset
An alarm condition will cause the applicable alarm to activate its corresponding relay and LED. If alarm 1, alarm 2,
or fault alarms have been programmed for latching relays, an alarm reset function must be activated to reset the
alarms after an alarm condition has cleared. To reset the alarms, simply wave the programming magnet over either
“PGM 1” or “PGM 2”, momentarily, while in normal operations mode and note that the corresponding alarm
LED(s) turn off.
3.9.3 Other Alarm Functions
Alarms are factory programmed to be non-latching, de-energized; and to f ire under ascending gas conditions. The
fault alarm relay is programmed as normally energized which is useful for detecting a 24VDC power source failure.
All alarm functions are programmable via jumper tabs. Changing alarm functions requires the sensor housing to be
opened, thus declassif ication of the area is required. See section 3.5.5-e for details.
3.10 P
ROGRAM
F
EATURES
Model IR-640 MicroSafe™ Sensors incorporate a comprehensive program to accommodate easy operator interface
and fail-safe operation. Program features are detailed in this section. Each sensor is factory tested, programmed, and
calibrated prior to shipment.
Over Range
When the sensor detects gas greater than 100% of the full-scale range, it will cause the display to f lash “OVER-
RANGE” on and off.
Optics Life
The Optics Life feature is a reference based on the signal output from the optical sensor. When an optical sensor
life of 25% or less remains, the optical sensor should be replaced within a reasonable maintenance schedule.
Calibration Fault
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.17