Detcon DM-200 - Manual (Page 29)

Model DM-200
DM-200 Instruction Manual Rev. 2.0 Page 25 of 40
Probable Causes: Incorrect cal gas delivery, Bad calibration gas, Failing Electrochemical sensor, Inadequate
wait time, Incorrect Cal gas value.
1. Verify that existing Sensor Life% value is not < 25%.
2. Verify that the correct span gas value is entered in the program.
3. Determine if failing Auto Span is due to inadequate signal or inadequate stability.
4. Check cal gas flow, type, concentration, and expiration date (validate cal gas with pull tube).
5. If failing AutoSpan stability test, apply cal gas for 3-5 minutes before executing AutoSpan.
6. If failing AutoSpan signal test, change-out electrochemical sensor and retry AutoSpan.
Clearing "Span Cal" Fault Message
1. This message can be cleared by performing either a successful AutoSpan or AutoZero.
"Zero Cal Fault" Message
Probable Cause: Zero cal during High Exposure
1. Verify there is no target gas when doing a zero cal.
2. Use “Zero Air” if necessary.
3. Recalibrate zero after 5 minutes to clear message.
"Sensor Fault" Message
Probable Cause: Zero baseline has drifted negative, Excessive temperature drift.
1. Re-Calibrate Zero.
2. If "Sensor Fault" is intermittent and correlates with temperature – Contact Detcon.
4-20 mA not matching LCD display
Probable Causes: Various
1. Verify adequate operating voltage (> 11.5 VDC).
2. Reads 1.1 mA with "Missing Sensor" - unplug and replug ISM, and/or un-power and re-power unit.
3. Reads 3.5 mA – Unit out of Normal Operation, user must clear out of user interface software.
4. Reads > 0.2 mA in accurately – 4-20 mA should be recalibrated, Contact Detcon for procedure.
"Memory Error" Message
Probable Cause: Faulty memory chip.
1. Exchange UTM and ISM with functioning UTM and ISM and determine which is faulty.