Teledyne Analytical Instruments LXT-380, Instructions Manual

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LXT-380 Universal Transmitter Calibration
Teledyne Analytical Instruments
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around 6000 μS (correlation factor 0.1667). All three solutions have a
TDS of 1000 ppm but the conductivities are 1400 μS, 2000 μS and 6000
μS. A TDS measurement is only valid for a solution with the same
chemical make up as the solution used for calibration.
Calibration is accomplished in two steps; Step 1 Conductivity
AUTO Calibration of the sensor (see section 4.7.1 above) and then Step
2 correlation of conductivity to the TDS. The second step can be done
by entering the correlation factor into the CONFIG →SENSOR→ TDS
menu or by standardizing the sensor in a solution of known TDS in the
CAL→STAND menu by entering the TDS value. Since the correlation
of conductivity to concentration is not linear it is best to calibrate the
sensor near the measured value.
4.6.1 STANDARDIZE
With the sensor in the process solution, take a grab sample from the
process and determine the TDS using a qualified laboratory method.
4.7 RESISTIVITY SENSORS
AUTO Calibration recognizes Air for zero point (Cal 1) and a Meg-
Ohm process solution for the span (Cal 2). Use the actual process
solution or a solution near the resistivity of the process solution. The
example below uses air and 15 MΩ. The Cal 1, air calibration value is
very stable and need not be done for every calibration.