Density Meter LB 444 SECTION 6. BASICS OF DENSITY MEASUREMENTS
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6. BASICS OF DENSITY MEASUREMENTS
6.1 Temperature Compensation
The data for temperature compensation (TC1, TC2) and the reference tem-
perature have to be entered before starting calibration. The temperature
compensation is then turned on automatically.
Temperature fluctuations in the product to be measured are usually associated
with density fluctuations. This means that a different density is indicated, al-
though the concentration of the product did not change. Temperature compen-
sation corrects for this effect.
Temperature Measurement
The product temperature can be measured either
a) with the resistance thermometer Pt 100 (see also section 3.4 Installation of
Resistance Thermometer Pt 100)
or
b) by entering the product temperature as current signal 0 - 20 mA.
The respective operating mode is selected in the Config Instrument / Operating
Mode menu.
If the temperature is measured with the resistance thermometer Pt 100, the
evaluation unit carries out a linearization of the Pt 100 curve. The range of the
current signals is entered in the Parameter menu (parameters Current input
range and Temp. limit values).
Monitoring the Temperature Signal
The temperature compensation is activated when selecting the respective in-
strument configuration and the temperature signal is monitored. The error mes-
sage "Error Temp. measurement" is displayed with
a) PT 100 connection: When the measured temperature < -200 °C.
b) Current signal 4 - 20 mA: When the input signal < 4 mA.
A current input signal 0 - 20 mA is not monitored.
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