PRONOVA FOS/TAC 2000, User Manual

FOS/TAC 2000 

CALIBRATION 

812-04.2015-EN 

FOS/TAC 2000 User Manual 

16 

7.2

Calibration procedure 

 
 
Prior to calibration, rinse the pH electrode thoroughly with distilled water and use cellulose tissue to dry. 

 
The following process of calibrating the pH electrode is split up to two points, where calibration point 1 is determined with the pH4 
buffer solution and calibration point 2 with the pH7 buffer solution. For this purpose, first fill approx. 30ml of the pH4 buffer solution 

into a 50-ml beaker, put in a stir stick, and place onto the magnetic stirrer. 
 

In the main menu, use the 



 and 



 keys in order to select the “Calibration and subsequently “pH electrode” menu options and 

click “OK” to confirm each selection.  
 

Dip the electrode system into the buffer solution pH=4.0 (calibration point 1) and watch the pH and temperature on the display of the 
IS7430. As soon as both measured values provide stable values, you can click <OK> in order to accept calibration point 1.  
 

Then rise the electrode system with distilled water and use cellulose tissue to pat dry.  
 

Then dip the electrode into the buffer solution pH = 7.0 for calibration point 2 and wait again until the pH and temperature have 
stabilized. Click <OK> once again in order to accept calibration point 2. 
 

The IS7430 uses the two calibration points in order to calculate the new values for gradient and offset. These are compared to limits 
stored internally in the device. As soon as the values are within these limits, they are then shown on the display of the IS7430. 

Record these values and compare to earlier calibration results. You can then either click <OK> to accept the calibration result, or 
<ESC> to reject. The display of the IS7430 shows the “ERROR” message if the calibration process was not correct. The old 
calibration data is maintained if the calibration process is aborted.

Reasons for strongly diverging calibration values can be imprecise or used-up calibration fluids, worn electrodes or manual 
calibration errors. In such a case, please repeat the calibration process, allow the electrodes more time to stabilize, service or 
replace the electrode system and/or the calibration fluids.  

Dispose of buffer solutions after use!

 
Following this, rinse the electrode once again with distilled water and dry. In order to protect the membrane from drying out, we 

recommend always attaching the protective cap with KCl solution during measuring intervals. 

Calibration 
pH electrode 
 

Buffer pH4 
 

Calibration 
pH electrode 
 

Buffer pH7 
 

Calibration 

pH Electrode 

Perist. Pump 

OK 

OK 

Measuring 

Calibration 

Stirrer 
A/D Values 
 

OK 

OK 

Save 
Calibration? 
Yes:    OK 
No:     ESC 

 
 Calibration 

  canceled 

 
 Calibration 

  finished 

OK