Yokogawa EXA ISC202 2-wire Conductivity Transmitter/Analyzer - Manual (Page 78)

IM 12D06A03-01E
2-6 Appendix
12-4-1. Settings Performed in Maintenance Mode
12-4-1-1 Calibration with solution of known conductivity
Refer to Sec. 6 for Calibration
1. When is calibration required?
Inductive conductivity meters should be calibrated before they are first used, but should not need peri-
odic calibration after that: the ISC202/ISC40 inductive conductivity measuring system passes a current
through the measured liquid to measure its conductivity; if there is little clearance (less than 30 mm)
around the sensor then this can affect the accuracy of calibration, and the sensor should be calibrated
before use. Also if the sensor surface becomes corroded or contaminated, you should recalibrate it.
2. How is calibration performed
Calibration normally involves measuring a liquid of known conductivity at a known temperature, and
adjusting the meter to read the correct value. Since the reading is affected by the mounting, the sensor
should be calibrated on site after installation.
You can mix standard solutions of KCl or NaCl for calibration. The temperature of the standard solution
should be maintained at the reference temperature. Conductivity tables for NaCl and KCl are shown in
Table 6-1 and 6-2. The other conductivity tables may be found in IEC and other standards. You can
also calibrate the sensor with a solution of arbitrary concentration by calibrating it against a standard
conductivity meter (we recommend Yokogawa's Personal Conductivity Meter). The reference tempera-
ture of both meters should be the same, and as far as possible you should perform the calibration at the
reference temperature, as there will otherwise be temperature compensation errors if the temperature
compensation functions of the two meters are not exactly the same.
When calibration is performed, the cell constant ("Installation Factor") is corrected (see Sec. 5-1-2).
12-4-1-2 Selecting Items for Display
Refer to Sec. 5-1-3 and 5-1-4
1. Selecting Items for Display
You can select and display the following items on the "message" auxiliary display:
• Measured values
• Error messages
• Other messages
The shipping-time default is for temperature to be displayed.
You can change this default to any item on the list in 2. below.
2. What items can be displayed?
Temperature : Current value
Output : Current value
Weight% : Current value
Installation Factor : See Sec. 6 for Calibration, or Sec. 5-1-2 for Installation Factor
adjustment
Reference Temperature : See Sec. 5-3-3 for Reference Temperature setting
Temperature Compensation : For default "standard" temperature compensation, NaCl is displayed
When manual temperature compensation is selected, "T.C. coefficient" is displayed.
When matrix temperature compensation is selected, You need to specify "reference temperature", "tem-
perature compensation coefficient", and (non-linear) "compensation characteristic".
3. Examples
You can display output signal value (range 4 to 20 mA) on the "message" auxiliary display to check the
value. For example, if :
Measurement range : 0 to 100 μS/cm, and
Process value : 60 μS/cm, then
Output value : 13.6 mA is displayed.