Detcon 1000 - Manual (Page 21)

Mdl 1000 H2S E-Chem / Inst. Air
Model 1000 H2S E-Chem w Instrument Air Rev. 1.1 Page 17 of 28
Additional Notes
a) Upon entering the calibration menu, the 4-20mA signal drops to 2mA and is held at this level until the
sensor returns to normal operation.
b) If during calibration the sensor circuitry is unable to attain the proper adjustment for span, the sensor will
enter into the calibration fault mode which will activate fault alarm functions and cause the display to
alternate between the sensor’s current status reading and the calibration fault screen which appears as:
“CAL FAULT”. If this occurs, attempt to recalibrate by re-entering the calibration menu. If the sensor
fails again, refer to Section 13 Troubleshooting
c) After span calibration, the alarm relays remain inactive until the sample gas concentration falls below both
set alarm levels. The alarms will then become active again.
7. Programming Alarms
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 40% of full-scale range. Both alarms can be set from 10 to 90% of full-scale range. The following
procedure is used to change alarm set points:
a) Enter the programming menu by holding the programming magnet stationary over “PGM 2” for 30
seconds until the display reads “VIEW PROG STATUS”, and withdraw the magnet. 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 @ ###PPM”, and withdraw the magnet.
Use the programming magnet to adjust the display reading using “PGM 1” to increase or “PGM 2” to
decrease the reading until the desired alarm set point is reached. Exit to the programming menu by
holding the programming magnet over “PGM1” for 3 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 @ ###PPM”, and withdraw the magnet.
Use the programming magnet to adjust the display reading using “PGM 1” to increase or “PGM 2” to
decrease the reading until the desired alarm set point is reached. Exit to the programming menu by
holding the programming magnet over “PGM1” for 3 seconds.
d) Exit back to normal operations by holding the programming magnet over “PGM 2” for 3 seconds, or, the
sensor will automatically return to normal operation in 30 seconds.
7.1 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.
7.2 Other Alarm Functions
Alarms are factory programmed to be non-latching, de-energized; and to fire 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 declassification of the area is required.