< 7. Startup >
7-7
IM 11M12D01-01E
7.9 Calibration
To calibrate this instrument, the procedure is to measure zero gas and span gas and set the
instrument to read the known concentrations. The procedure for both zero and span calibration,
or for either zero or span calibration, can be performed manually from the touch display, or can
be performed semi-automatically using contact signal inputs to start calibration, (allowing preset
calibration and stabilization times), or it can be performed automatically at preset intervals. Here we
explain manual calibration.
7.9.1 Setting Calibration Gas Concentration
Before calibrating, you need to set the (oxygen) concentration of the gas you will use for calibration.
Here we explain how to do this. Note that calibration-related settings apply to all channels, you can’t
set different values for individual channels.
A gas with a known oxygen concentration is used for calibration. Normal calibration is performed
using two different gases: a zero gas of low oxygen concentration and a span gas of high oxygen
concentration. In some cases, only one of the gases needs to be used for calibration. However, even if
only one of the gases is normally used, calibration using both gases should be done at least once.
The zero gas normally used has an oxygen concentration of 0.95 to 1.0 percent oxygen by volume
with a balance of nitrogen gas (N
2
). The span gas widely used is clean air (at a dew-point temperature
below -20°C and free of oily mist or dust, as in instrument air).
For best accuracy, as the span gas use oxygen whose concentration is near the top of the
measurement range, in a nitrogen mixture.
Shipping-time default setting for zero gas is 1.0% O
2
, and for span gas is 21.0% O
2
.
<Setting Procedure>
1) Touch the Setup key to switch to the [Execution/Setup] display.
2) Select [Maintenance] to display the Maintenance display.
3) From the Maintenance display, select [Calibration setup].
4) Select [Zero gas conc] and touch the Enter key to display the numerical entry display. Enter the
oxygen concentration of the zero gas you plan to use. To enter a concentration of 0.98% O
2
,
enter 00098.
5) Select and set the Span Gas in the same manner.
Enter
Calibration setup
F7-9E.ai
Mode: Auto
Points: Span-Zero
Zero gas conc: 0 . 9 8 %
Span gas conc: 2 1 . 0 0 %
Timing
Cal. history initialize
Figure 7.9 Calibration Setting
NOTE
If instrument air is used for the span gas, dehumidify the air by cooling to the dew point of -20°C and
remove any oil mist or dust
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