Hach 410M Manual Básico Del Usuario página 23

behaves in O . As a different voltage is used at the anode to measure O
2
measurement takes a long time to stabilize. To facilitate the follow up after an "O
negative values can be displayed.
7.4.3 TC sensor calibration
7.4.3.1 Calibration of the measured gas
1. Before initiating a calibration process, the calibration parameters must be set by pressing on the
Modify button. The last calibration parameters are memorized, so this step can be ignored if the
correct parameters are already set. Similarly, if only the calibration value has changed, then this
can be updated directly instead of pressing the Modify button.
Option
Gas Phase
Gas unit type
Gas unit
Liquid
Value
Hold during
calibration
Automatic calibration
stop
2. Press OK to start calibration
• A calibration screen will be displayed showing current measurement data which is continually
refreshed.
• The value "% ideal current" is a percentage of the current against the ideal current for the
membrane type selected. If this percentage is not within the accepted range, an error message
is displayed and the calibration process fails. A warning message can be displayed when this
value is close to the boundaries, but when calibration can be accepted.
• The message is first displayed in the result box. The dialog box with the error message or the
warning is displayed when the finish button is pressed.
• The value "% last calibration" shows the ratio between the current measurement and the
previous sensor calibration.
• The value "% variation" indicates the variation during the last 3 measurements, which is the
stability of the measurements. A variation as low as possible is needed for a precise
calibration.
• The display shows the actual calibration parameters, and the actual readings (temperature,
barometer, current).
7.4.4 Barometric pressure calibration
Note: The barometric pressure sensor has been factory calibrated but should be periodically verified with a
precision certified barometer. This is only necessary if measuring in gas phase with fraction units (%, ppm).
The upper box shows the barometric pressure as measured by the instrument.
Using a precision certified barometer measure barometric pressure in the location where the
measuring instrument is used. Compare the values and if they are the same press Cancel, otherwise
enter the new barometric pressure value in the lower box and press Validation to validate the new
setting.
Description
Select liquid or gas (direct calibration only)
Partial, fraction or dissolved (dissolved is for calibration in a liquid
only)
The list of available units depends on unit type selected above.
Select as appropriate.
Enter the gas concentration according to the value in the calibration
media.
On by default, this stops any output from the instrument during the
calibration process to avoid sending invalid information to any
connected device.
If selected, when the stability criteria is reached, the calibration
process stops automatically.
and O , the O
2 3 3
in air" calibration,
3
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