Jenway 4510 User Manual
Page 14
3.5
Calibration with Standard Solution
Calibration of the unit and cell with standard solutions will only be necessary if:
1)
The cell constant is unknown.
2)
The cell constant has changed due to replatinising, wear or damage to the plates.
3)
An ATC slope other than 2%/°C is required (refer Special Calibration).
General Calibration
1)
Immerse the conductivity cell into the prepared standard.
2)
Select the MODE menu using the keypad.
3)
Press the CAL/CLR key. The unit will calibrate to the nearest standard.
3.3 Preparation of Conductivity Standards
Suitable conductivity standards are available commercially or these can be made up as required from
analytical grade reagents with reference to relevant physical tables.
Method for general purpose Conductivity Standard
Accurately weigh out 0.746 grammes of dried A.R. grade Potassium Chloride (KCl) and dissolve in 1
litre of good quality water. This produces a 0.01N solution with a conductivity of 1413µS at 25°C.
Storage
This solution must be stored in a plastic container and the air space above the solution should be kept
to an absolute minimum. The shelf life of 1 week can be increased by storing below 4°C, but where
any doubt exists about the viability of stored solution a fresh batch should be prepared.
3.4
Calibration with Known Cell Constant
1.
Connect a standard pre-calibrated cell to the unit.
2.
Select SETUP mode on the display using the Left arrow key.
3.
Set the cell constant value as indicated on the body of the conductivity cell (refer Section 3.2.1)
The standard X1.0 cell has a cell constant range from 0.8 to 1.20 and is generally calibrated to
2 decimal places. The display should be set to indicate this figure exactly.
The X10 cell has a cell constant range from 8.0 to 12.0 and is generally calibrated to 2 decimal
places. The display should be set to indicate this figure.
4.
Set the Temperature Coefficient value (refer Section 3.2.2).
5.
Select the required reference temperature (refer Section 3.2.3).
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