eutech-instruments alpha ph 190 18 din phorp controllertransmitter Benutzerhandbuch

Seite von 39
 
 
- 11 - 
6  PH CALIBRATION 
IMPORTANT: When Calibration mode is entered, controller automatically goes into 
a “HOLD” mode where the 4-20 mA output freezes and relays are de-activated (if it 
was in an activated condition). Upon return to measurement mode, both 4-20mA 
output and relay activities resume, depending on settings. 
 
The 
αlpha pH 190 controller features seven preset buffer values (pH 1.68, 4.01, 
6.86, 7.00, 9.18, 10.01, 12.45) for quick auto-calibration at one or two points. The 
first calibration point must be pH 6.86 or 7.00.
 When you calibrate this 
instrument, you need to use FRESH standard pH buffer solution that matches 
these values. 
 
NOTE: If you are in ORP mode, see Program 3.0 for instructions on switching to 
pH mode. 
1.  Press CAL / ENTER key to directly access the Calibration mode when the unit 
is in pH measurement mode. 
NOTE: Instead of pressing the CAL/ENTER key, you can also enter the Calibration 
mode using the password code procedure as explained in Section 5. 
 
2.  The display scrolls BUFF and either pH 7.00 or 6.86. You must calibrate at 
one of these two buffers for the first calibration. Use ▲ / ▼ keys to select pH 7.00 
or 6.86. 
3.  Make sure the electrode is in the buffer solution. In ATC mode, you must also 
immerse the temperature sensor in the buffer solution. In the symmetrically high-
resistance measurement mode, you must also immerse the solution ground 
(potential equalization pin) in the buffer. 
4.  Allow the electrode time to stabilize. 
5.  Press ENTER. The instrument will blink with the un-calibrated pH value 
corresponding to the mV output of your pH probe. If the value displayed differs 
substantially from the buffer value, this indicates electrode drift. Consider replacing 
your electrode. 
 
6.  Press ENTER to confirm the buffer value. The display blinks the calibrated 
value twice, shows “DONE” and moves to the next buffer. 
 
NOTE: Buffer must be within ±1.5 pH of the value you are calibrating to or Err1 will 
be displayed flashing. To clear the Err1 display and return to calibration mode, 
press ▲ / ▼ keys together.