YSI IQ SensorNet FDO Sensor - Manual (Page 20)

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Measuring / Operation FDO
®
70x IQ ...
 With air temperatures under 5 °C we recommend performing the
function check and user calibration not in air but in air-saturated
water that has a higher temperature. You obtain air-saturated water
by pouring water several times in and out of two vessels so that it
sparkles.
4.2.2 Function check
A function check is the simplest way to determine whether the sensor
needs to be cleaned or user-calibrated.
Principle The function check can either be done in water vapor-saturated
air or in air-saturated water (see C
HECK OR CALIBRATION MEDIUM on
page 4-1).
Steps Generally, a check on the IQ
S
ENSOR
N
ET is carried out as follows. Sys-
tem specific details are given in the respective IQ
S ENSOR N ET system
operating manual.
2 cm
1 Switch to the measured value display with <M> and select the
FDO
®
70x IQ ... sensor.
2 Press <C>.
The next step switches on the maintenance condition for the
sensor. A corresponding message appears on the display.
3 Confirm the note with <OK>.
The maintenance condition is active.
4 Select the TEST procedure and press <OK>.
5 Put the sensor into the calibration position (water vapor-satu-
rated air or air-saturated water - see section 4.2.1).
6 Press <OK>.
The sensor starts the check. The display switches to the mea-
sured value display. The CAL indicator flashes instead of the
main measured value. At the same time, the momentary rela-
tive slope flashes as the secondary measured value with the
addition of TEST. The process ends automatically as soon as
the measured values meet the criterion for the stability control.
With a great temperature difference between the sensor and
the environment this may take a while. Subsequently, the main
measured value and temperature are displayed.