D e t e c t i o n
NEO Photo-ionization detector
User Manual
D e t e c t i o n
14
Span Calibration
This procedure determines the second (and third, if 3-Point Cal is selected in Monitor Setup) point(s)
of the sensor calibration curve. One or two cylinders of standard reference gas (span gas) fitted with
a 500 cc/min flow-limiting regulator or a flow-matching regulator is the simplest way to perform this
procedure. The span gas concentration should be chosen to be near the highest concentration of actual
measurements expected. It is also preferred to use the same balance gas (e.g., air or nitrogen) as occurs in
the actual measurements.
To perform a Span calibration, connect the calibration adapter to the inlet port of the instrument, and
connect the tubing to the regulator or gas bag. Select ‘Span Calib’ by pressing the Right key to enter the
submenu. The message ‘Please Apply Gas’ is displayed. Start the span calibration by pressing the Up key,
which begins a 30- second countdown.
Note: To abort the Span calibration, press the Left key at any time during the process. The confirmation
message ‘Span is aborted!’ appears followed by the next menu item.
When Span 1 calibration is complete, a message similar to this is displayed (the
value is an example only):
3-Point Calibration
If ‘3-Point Cal.’ is enabled (see Monitor Setup), proceed to perform Span 2 in the same manner as for Span
1.
3-Point calibration should be used whenever enhanced accuracy is required. It is especially
recommended for measurements above about 500 ppm, where PID response is not quite as linear.
Set Calibration Gas
In the Set Cal. Gas menu, select the calibration gas from either the mPower Gas Library or the user’s
Custom Gases list. Custom Gas names and parameters can only be set up through the mPower Suite
software.
Span 1 is done!
Reading = 10.ppm
