Detcon PI-600 - Manual (Page 24)

Span calibration consists of entering the calibration function and following the menu-displayed instructions. The dis-
play will ask for the application of span gas in a specif ic concentration. This concentration must be equal to the calibra-
tion gas level setting. The factory default setting for span gas concentration is 50% of range. In this instance, a span gas
containing a concentration equal to 50% of range is required. If a span gas containing 50% of range is not available,
other concentrations may be used as long as they fall within 10% to 90% of range. However, any alternate span gas con-
centration value must be programmed via the calibration gas level menu before proceeding with span calibration.
Follow the instructions below for span calibration.
a) Verify the current calibration gas level setting as indicated by the programming status menu. To do this, follow the
instructions in section 3.9 and make note of the setting found in listing number 2. The item appears as
“GasLevel @ xxPPM”.
b) If the calibration gas level setting is equal to your calibration span gas concentration, proceed to item “f”. If not,
adjust the calibration gas level setting so that it is equal to your calibration span gas concentration, as instructed in
items “c” through “e”.
c) Enter the programming menu by holding the programming magnet stationary over “PGM 2” for 15 seconds 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 Cal Level, Set Response Factor, and Set Zero Offset.
d) From the programming menu scroll to the calibration level listing. The menu item appears as: “SET CAL
LEVEL”. Enter the menu by holding the programming magnet stationary over “PGM 1” for 3 seconds until the
display reads
“CalGas @ ##PPM”, then withdraw the magnet. Use the programming magnet to make an adjust-
ment to “PGM 1” to increase or “PGM 2” to decrease the display reading until the reading is equal to the desired
calibration span gas concentration. Exit the programming menu by holding the programming magnet over “PGM1”
for 3 seconds.
e) Exit back to normal operation by holding the programming magnet over “PGM 2” for 3 seconds, or automatically
return to normal operation in 30 seconds.
f) From the calibration menu “1-ZERO 2-SPAN” proceed into the span adjust function by holding the program-
ming magnet stationary over “PGM 2” for 3 seconds then withdraw the programming magnet. At this point the
display will ask for the application of the target gas and concentration. The display reads “APPLY xxPPM ISO”
The x’s here will indicate the actual concentration requested.
g) Apply the calibration test gas at a f low rate of 200 cc/min. After applying the span gas, hold your f ingertip (block-
ing) over the exit port of the cal adapter for 10-30 seconds. This helps to expedite the purging of the internal sen-
sor chamber. As the sensor signal changes, the display will change to “AutoSpan xxPPM”. The “xx” part of the
reading indicates the actual gas reading which will increase until the sensor stabilizes. When the sensor signal is sta-
ble it will auto span to the correct ppm reading and the display will change to “SPAN COMPLETE” for 3 sec-
onds, then to “SENSOR LIFE: xxx%”and then “REMOVE GAS”. Remove the gas. When the signal level has
fallen below 10% of full scale, the display will return to the normal operating mode.
NOTE 1: If there is not a minimal response to the cal gas in the f irst minute, the sensor will enter into the calibra-
tion fault mode which will cause the display to alternate between the sensor’s current status reading and the calibra-
tion fault screen which appears as: “SPAN FAULT #1” (see section 3.8.3).
NOTE 2: If during the auto-span function the sensor fails to meet a minimum signal stability criteria, the sensor
will enter the calibration fault mode which will cause the display to alternate between the sensor’s current status
reading and the calibration fault screen which appears as: “SPAN FAULT #2” (see section 3.8.3).
3.8.3 Additional Notes
1. Upon entering the calibration menu, the 4-20 mA signal drops to 2 mA and is held at this level until you return to
normal operation.
2. If during calibration the sensor circuitry is unable to attain the proper adjustment for zero or span, the sensor will
enter into the calibration fault mode which will activate the fault LED (see section 3.10) and will cause the display to
alternate between the sensor’s current status reading and the calibration fault description. In these cases, the previous
calibration points will remain in memory. If this occurs you may attempt to recalibrate by entering the calibration
menu as described in section 3.8.1-a. If the sensor fails again, defer to technical trouble shooting (see section 3.13).
PI-600 Toxic Gas Sensors PG.24