Instruction manual

84
MODEL XMT-P pH/ORP SECTION 9.0
CALIBRATION — pH
9.3 PROCEDURE — MANUAL TWO-POINT CALIBRATION
1. Obtain two buffer solutions. Ideally, the buffer values should bracket the range of pH values to be measured.
2. Remove the pH sensor from the process liquid. If the process and buffer temperatures are appreciably different,
place the sensor in a container of tap water at the buffer temperature. Do not start the calibration until the sensor
has reached the buffer temperature. Thirty minutes is usually adequate. Make a note of the temperature.
3. Press MENU. The main menu appears. Choose Calibrate.
4. Choose pH.
5. Choose BufferCal.
6. Choose Manual.
7. Choose Buffer1.
8. Rinse the sensor with water and place it in buffer 1. Be sure the glass
bulb and reference junction are completely submerged. Swirl the sensor.
9. The reading in the top line is the live pH reading. Wait until the live read-
ing is stable. Then, use the arrow keys to change the reading in the sec-
ond line to the match the pH value of the buffer. The pH of buffer solu-
tions is a function of temperature. Be sure to enter the pH of the buffer
at the actual temperature of the buffer.
10. Remove the sensor from buffer 1 and rinse it with water. Place it in
buffer 2. Be sure the glass bulb and the reference junction are com-
pletely submerged. Swirl the sensor. Choose Buffer2.
11. The reading in the top line is the live pH reading. Wait until the live read-
ing is stable. Then, use the arrow keys to change the reading in the sec-
ond line to the match the pH value of the buffer. The pH of buffer solu-
tions is a function of temperature. Be sure to enter the pH of the buffer
at the actual temperature of the buffer.
12. The screen at left appears momentarily.
13. If the calibration was successful, the transmitter will display the offset
and slope (at 25°). The display will return to the screen in step 5.
14. If the slope is out of range (less than 45 mV/pH or greater than 60
mV/pH) or if the offset exceeds the value programmed in Section 7.4, an
error screen appears. The display then returns to the screen in step 6.
15. To return to the main display, press MENU then EXIT.
Calibrate Hold
Program
Display
Cal?
pH Temp
BufferCal?
Auto Manual
ManualCal?
Buffer1 Buffer2
ManualCal?
Buffer1 Buffer2
pH Standardize
Slope BufferCal
Live 7.00pH
Buf1 07.00pH
Live 10.01pH
Buf1 10.01pH
Cal in progess.
Please wait.
Offset 0mV
Slope 59.16@25
°C
Calibration
Error