Detcon DM-200 - Manual (Page 24)

Model DM-200
DM-200 Instruction Manual Rev. 2.0 Page 20 of 40
adjustment. Use the programming 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 year.
To retain the newly entered value, hold 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.
3.7 Program Features
Detcon UniTox™ toxic gas 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.
Sensor Life
The sensor life feature is a reference based on signal output from the sensor cell. When a sensor life of 25% or
less remains the sensor cell should be replaced within a reasonable maintenance schedule.
Data Logging
The data logging feature records the most recent 8 hours of data: time-weighted average (TWA) and peak (PK)
reading. The menu item appears as “TWA: xx PPM / PK: xx PPM@ xx Min”. TWA is a rolling 8 hour
average updated at 30 minute intervals. The peak (PK) reading is the instantaneous peak reading recorded in
the last 8 hours and the “@ –xx Min” represents the “number of minutes ago” that the peak reading took place.
For example: “PK: 33 PPM@ –360 Min” explains that a peak reading of 33 ppm took place 6 hours (360
minutes) ago.
NOTE: For oxygen sensing, the Peak (PK) reading is the lowest reading recorded in the last 8 hours
Over Range
When the sensor detects gas greater than 100% of range, it will display the highest reading of its range and an
output of 20 mA.
Under Range Fault
If the sensor should drift below a zero baseline of –10% of range, the display will indicate a fault: “Sensor
Fault” and report an output of 3.5 mA. This is typically fixed by performing another zero cal.
Span Calibration Fault
If during calibration the sensor circuitry is unable to attain the proper adjustment for span, the sensor will enter
into the span calibration fault mode and cause the display to alternate between the sensor’s normal operation
reading and the calibration fault screen which appears as: “Span Cal Fault”. The previous calibration
settings will remain saved in memory.
Zero Calibration Fault
If during calibration the sensor circuitry is unable to attain the proper adjustment for zero, the sensor will enter
into zero calibration mode and cause the display to alternate between the sensor’s normal operation reading
and the calibration fault screen which appears as: “Zero Cal Fault”. The previous calibration settings will
remain saved in memory.