Conductivity
Cond 7310
24
ba75933e04
06/2013
Criteria for a stable
measured value
The
Stability control
function checks whether the measured values are stable
within the monitored time interval.
The minimum duration until a measured value is assessed as stable is the mon-
itored time interval. The actual duration is mostly longer.
5.1.2 Measuring the temperature
For reproducible conductivity measurements, it is essential to measure the
temperature of the test sample.
The temperature is automatically measured by the temperature sensor
(NTC30 or Pt1000) integrated in the sensor.
5.2
Calibration
5.2.1 Why calibrate?
Aging slightly changes the cell constant, e. g. due to coatings. As a result, an
inexact measured value is displayed. The original characteristics of the cell can
often be restored by cleaning the cell. Calibration determines the current value
of the cell constant and stores this value in the meter.
Thus, you should calibrate at regular intervals (we recommend: every 6
months).
5.2.2 When to calibrate?
After connecting a sensor
Routinely within the framework of the company quality assurance
When the cleaning interval has expired
5.2.3 Determining the cell constant (calibration in control standard)
You can determine the actual cell constant of the conductivity measuring cell
by calibrating with the control standard in the following ranges:
0.450 ... 0.500 cm
-1
(e.g. TetraCon 325 with a nominal cell constant of 0.475
-1
)
Measured
parameter
Time interval
Stability in the time interval
Conductivity
ϰ
10 seconds
Δ
: Better than
1.0% of measured value
Temperature
15 seconds
Δ
: Better than 0.5 °C
The TetraCon 325, KLE 325, LR 325/01 and LR 325/001 conduc-
tivity sensors have an integrated temperature sensor.
Summary of Contents for Cond 7310
Page 58: ...Index Cond 7310 58 ba75933e04 06 2013...
Page 59: ......
