Maintenance
44
Calibrating the unit
— Ensure that the sensor is warmed up before it is calibrated. See the sensor
data sheet for the warming-up time.
— For some sensors (such as oxygen sensors) the function » zero-point
calibration « is simply a test of the sensor function. The zero point is not ac-
tually calibrated since this is not necessary for these sensors.
— For critical applications, the calibration intervals should be defined in ac-
cordance with the recommendations in EN 50073
1)
, EN45544-4
2)
and na-
tional regulations.
Note the calibration sequence!
First check the zero point and calibrate it if necessary, immediately after
this, check the sensitivity and adjust it as necessary.
— Never calibrate the sensitivity before calibrating the zero point.
— Calibration cannot be carried out if the date and time are not set.
Setting the date and the time, page 67.
— Calibration menu, page 58 to page 59.
— Zero gas and test gas: see the information in the sensor data sheet and on
the pages 118 to 121.
Calibrating with test gas
Use a test-gas cylinder with pressure-reduction valve (a stainless-steel
pressure reduction valve for aggressive gases). Observe the information in
the sensor data sheet.
1 Mount a calibration adapter Part No. 68 06 978 (with two hose connectors)
on the Polytron 7000.
Vent the test gas leaving the adapter into a fume cupboard or into the open
air (with a hose connected to the second connector on the calibration
adapter).
1)
EN 50073 – Guidelines for selection, installation, use and maintenance of devices for
the detection and measurement of flammable gases and oxygen.
2)
EN 45544-4 – Electrical devices for the direct detection and direct concentration
measurement of toxic gases and vapours – Part 4: Guidelines for selection, installa-
tion, use and maintenance.
CAUTION
Test gas must not be inhaled. Risk to health! Care must be taken about
the risks which can arise when using test gas; hazard instructions and safety
advice must be observed.
For details, see appropriate DIN Safety Data Sheets.
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