Detcon CX-DM - Manual (Page 19)

Model CX-DM
sensor is in-calibration mode. This bit will remain set until the program returns to normal
operation.
3. The ITM will display the following sequence of text messages as it proceeds through the AutoZero
sequence:
Zero Cal. . . Setting Zero. . . Zero Saved (each will scroll twice)
4. 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. This function is called "AUTO SPAN".
NOTE
Before performing AutoSpan Calibration, verify that the AutoSpan level matches the span
calibration gas concentration as described in Section 3.4.3.
Material Requirements:
• MicroSafe™ Programming Magnet (Detcon 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 (See Detcon for Ordering Information). 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
AutoSpan calibration.
NOTE
Ambient air should be used to calibrate O
2
deficiency sensors as long as the oxygen
concentration is confirmed to be 20.9%
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.
CX-DM Instruction Manual Rev. 1.3 Page 15 of 40