JUMO ecoTRANS Lf 03, Руководство по эксплуатации

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8 Calibration
8.1 General
The cell constants of conductivity cells stray somewhat depending
on the type and additionally change during operation (due to
deposits such as lime, or as a result of wear). This results in a
change of the output signal from the cell. It is therefore necessary
that the user is able to compensate for the deviations of the cell
constant from the nominal value, either by manual entry or an
automatic calibration of the cell constant K
rel
.
The conductivity of a solution varies with the temperature, so for
correct measurement both the temperature and the temperature
coefficient of the solution being measured must be known. The
temperature can either be measured automatically with a
temperature sensor, or set manually by the user. The temperature
coefficient can be determined automatically by the conductivity
transmitter, or entered manually.
The instrument uses the non-temperature compensated
measurements (TC = 0) at two different temperatures (the reference
temperature, e.g. 25°C, and a second temperature that will later on
be the working temperature) to determine the temperature
coefficient of the solution being measured.
The time intervals between calibrations depend on the conditions in
which the cell is used.
The instrument can draw your attention to a scheduled calibration
by means of the calibration timer.
see Chapter 12.7 “Calibration timer has run down”, page 60.