Calibrate the temperature sensor of this instrument. This instrument uses the temperature sensor connected to a measuring device to detect the temperature of the solution and automatically temperature-compensates the pH value only during calibration.
1. In the main window of pHM-40 Utility, click the (Temperature Calibration) button.

  

  The [Temperature Calibration] window will be displayed.
  In [Electrode temperature (Current)], the current temperature of the pH electrode is displayed.

2. Pull the grip (a) of the electrode holder to pull out the slider.
  

 

3. Remove the cable of the pH electrode from the clamp (A) in the slider. Loosen the knurled screw (B) that is securing the reel (C).
  NOTE: Do not remove the knurled screw. It may be lost.

  

 

4. Unclamp the clamp (a) on the rear side of the electrode holder and loosen the knurled screw (b).
  NOTE: Do not remove the knurled screw. It may be lost.

   

 

5. Remove the electrode cover, and pull the pH electrode up to remove it from the electrode holder.
  NOTE: Before removing the pH electrode from the flow cell, empty solution out of the flow cell with a syringe. Solution remaining in the flow cell will leak from the upper part of the retaining screw when the pH electrode is removed.
  HINT: If the pH electrode cable is being pulled, tilt the pH holder for easier maneuvering. Be sure to tilt the pH holder until the electrode holder comes into contact with the slider.

  

  CAUTION: Take care not to drop the pH electrode after removing it.
    The stem tube and the end of the pH electrode may be damaged if exposed to a heavy load because they are made of glass. The broken glass may also cause an injury. Attach the dedicated cap as necessary.

 

6. Remove the reel from the slider.
  NOTE: If the instrument is installed on CTO-40S, remove the fastener (A) and then take off the pH electrode cable from the reel.

  

 

7. Immerse the pH electrode and a calibrated thermometer in purified water in a beaker.

  

  NOTE: To measure the liquid temperature accurately, make sure to keep the pH electrode and the thermometer off the inner side and bottom of the beaker.

8. Read visually and enter the temperature reading of the calibrated thermometer in [Thermometer temperature].

9. Click [Calibration].
  Clicking this will calibrate the temperature. The value entered in [Thermometer temperature] will be set as the electrode temperature of the instrument.