Detcon CXT-IR, Operator'S Installation And Instruction Manual

Page: 46 / 52

Model CXT-IR
CXT-IR Instruction Manual Rev. 2.1 Page 42 of 48
•
Perform zero calibration.
•
Use zero air or N
2
source. (Section0
To enter Calibration Mode hold the magnet over PGM1 for 3 seconds. If the sensor is experiencing a fault
condition the “

” prompt will not appear until the fault(s) have been displayed. When the ITM enters Calibration
Mode the display will scroll “ Pgm1=Zero . . . Pgm2=Span ” twice before returning to Normal Mode (about 5
seconds).
•
AutoZero)
•
Allow more time for zero stabilization if this is a biased sensor type.
•
Execute successful span calibration. (Section 3.3.2AutoSpan)
•
Replace plug-in combustible sensor if error continues.
Stability problems
Probable Causes: Failed sensor, empty or close to empty cal gas cylinder, problems with cal gas and delivery
•
Check validity of span gas using pull tube or other means (check MFG date on cal gas cylinder).
•
Use proper cal gas regulators and tubing for highly corrosive gases.
•
If using Splashguard with Integral Cal Port, must use Calibration Wind Guard or air movement can
compromise span gas delivery.
•
Check for obstructions affecting cal gas hitting sensor face (including being wet, blocked, or corroded).
Sensor assemblies use CXT-IR series splashguard adapter assembly with integral filter. Clean or replace
if necessary.
•
Replace the plug-in combustible sensor.
Clearing problem
Probable Causes: Failed sensor, cal gas not removed at appropriate time, problems with cal gas and delivery,
background of target gas.
•
The sensor must recover to < 10% of range in < 5 min after Span calibration is complete
•
Use bottled air (zero air or N
2
) if there is a known continuous background level.
•
Check validity of span gas using pull tube or other means (check MFG date on cal gas cylinder).
•
Use proper cal gas regulators and tubing for highly corrosive gases
•
Check for obstructions affecting cal gas hitting sensor face (including being wet, blocked, or corroded).
Sensor assemblies use CXT-IR series splashguard adapter assembly with integral filter. Clean or replace
if necessary.
•
Replace the plug-in combustible sensor.
Poor Calibration Repeatability
Probable Causes: Failed sensor, use of wrong cal gas or problems with cal gas and delivery, interference gases.
•
Check validity of span gas with regulator and sample tubing in place using pull tube or other means
(check MFG date on cal gas cylinder).
•
Use proper cal gas regulators and tubing for highly corrosive gases (HF, HCI, Cl2, NH3, HBR, F2, etc.)
•
Check for obstructions affecting cal gas hitting sensor face (including being wet, blocked, or corroded).
Sensor assemblies use CXT-IR series splashguard adapter assembly with integral filter. Clean or replace
if necessary.
•
Replace the plug-in combustible sensor.
Unstable Output/ sudden spiking
Possible Causes: Unstable power supply, inadequate grounding, or inadequate RFI protection.
•
Verify power source is stable.
•
Verify field wiring is properly shielded and grounded.
•
Contact Detcon to optimize shielding and grounding.