Detcon CX-IR - Manual (Page 19)

Model CX-IR
d) Remove the zero gas and calibration adapter, if applicable.
3.3.2 AutoSpan
The AutoSpan function is used to span calibrate the sensor. AutoSpan should be performed periodically or as
required. AutoSpan should be considered after periods of over-range target gas exposure. Unless otherwise
specified, span adjustment is recommended at 50% of range.
NOTE
Before performing AutoSpan calibration, verify that the AutoSpan level matches the span
calibration gas concentration as described in Section 3.4.3 Set AutoSpan level.
Material Requirements:
• Detcon MicroSafe™ Programming Magnet (PN 327-000000-000)
• Splash Guard with integral Cal Port (Detcon P/N 613-120000-700) and Calibration Wind Guard
(Detcon PN 613-120000-700 ) -or-
• Threaded Calibration Adapter (Detcon PN 943-000006-132)
• Detcon Span Gas. Recommended span gas is 50% of range with target gas. Other suitable span gas
sources containing the target gas in air or N
2
balance are acceptable.
NOTE Contact Detcon for ordering information on span gas cylinders.
NOTE
A target gas concentration of 50% of range is strongly recommended. This should be
supplied at a controlled flow rate of 200 to 500cc/min, with 500cc/min being the
recommended flow rate. Other concentrations can be used if they fall within allowable
levels of 5% to 100% of range.
NOTE
The Calibration Wind Guard must be used when the Splashguard Adapter with integral Cal
Port is used. Failure to use the Calibration Wind Guard may result in an inaccurate
AutoZero calibration.
NOTE
It is generally not advised to use other gasses to cross-calibrate for span. Cross-calibration
by use of other gasses should be confirmed by Detcon.
CAUTION
Verification that the calibration gas level setting matches the calibration span gas
concentration is required before executing AutoSpan calibration. These two
numbers must be equal.
AutoSpan consists of entering calibration mode and following the displayed instructions. The display will ask
for the application of span gas in a specific concentration. The applied gas concentration must be equal to the
calibration gas level setting. The factory default setting and recommendation for span gas concentration is
50% of range. If a span gas containing the recommended concentration is not available, other concentrations
may be used as long as they fall between 5% and 95% of range. However, any alternate span gas
concentration value must be programmed via the Set AutoSpan Level menu before proceeding with AutoSpan
calibration.
a) Verify that the AutoSpan level is equal to the calibration span gas concentration. (Refer to View Sensor
Status in Section 3.4.1.) If the AutoSpan level is not equal to the calibration span gas concentration, adjust
the AutoSpan level as instructed in Section 3.4.3.
b) From normal operation, enter calibration mode by holding the programming magnet over PGM1 for 3
seconds.
CX-IR Instruction Manual Rev. 1.2 Page 15 of 34