a & b: Panel Screws Removable screws that allow access to the rechargeable batteries.
STANDARD pH CALIBRATION
Three buffer capsules are available, pH 4.00, pH 7.00, and pH 10.00. Use the buffers for calibration that
are closest to the pH range that you will be using. If your use will span the entire pH range, the instrument should be
calibrated with two buffers and checked with a third.
Make pH buffers by dissolving one capsule per 100 ml of deionized or distilled water. After complete
dissolution, the buffers should be properly stored in clearly labeled, tightly capped containers.
Commercially prepared buffers can also be used.
Check meter needle position Before the calibration procedure is performed, the meter needle position
should be checked when the meter is turned OFF. If the meter needle does not read zero, then the mechanical zero
screw should be used to adjust the needle to read zero.
Place pH electrode in pH 7.00 buffer. Sufficient buffer should be used to immerse the pH tip. Freshly
poured buffers should be used for each calibration so avoid using excessive amounts. The temperature control knob
should be adjusted to 25 °C or room temperature.
Make sure the front panel switch is set on pH and the expanded model is set to NORM.
Use the SET knob to adjust the analog needle to read a pH of 7.00.
Rinse the electrode with distilled water and carefully blot dry, using lint-free paper.
Do not wipe the electrode. Wiping can cause static electrical charges which can result in faulty readings.
Immerse the electrode in a second standard buffer, either pH 4.00 or pH 10.00. Allow time for
Use the SLOPE screw to adjust the readout to read exactly 4.00 or 10.00 depending on the second buffer
Rinse the electrode and blot dry. The meter is now ready for use in the pH mode.
The calibration of a pH meter is not permanent. It should be done on a regular basis and any time the pH
reading response becomes slow or erratic.
6.0 EXPANDED MODE CALIBRATION
For sensitive pH or millivolt measurements, the instrument should be used in the expanded (EXP) mode. For pH
measurements in the expanded mode, go to 6.2. For millivolt measurements in the expanded mode, go to 6.1.