YSI 60 - Manual (Page 14)

15. If you are performing a 3-point calibration, fill a clean container with the third value pH
buffer (pH 4 or 10, or pH 4.01 or 9.18) and immerse the probe into the solution. Make sure
that the temperature sensor is immersed.
NOTE: The third buffer must not be the same as the second buffer. For example; if the
second buffer was less than pH 7, the third buffer must be greater than pH 7.
16. Press the ENTER key. The Model 60 display will now show CAL at the bottom, SLOPE
will stop flashing and the pH calibration value (automatically sensed by the instrument) is
shown with one of the decimal points flashing. If the third pH buffer is less than the first
buffer (which was used to adjust the offset; usually pH 7), the left decimal point will flash. If
the third pH buffer is greater than the first, the right decimal point will flash.
1.0.0.0
pH
SLOPE
CAL
24.8
°C
Third buffer value
10
Right decimal flashes (until
reading is stable) for buffers
higher than first cal point
or
.4.0.1
pH
Third buffer value
SLOPE
CAL
24.8
°C
Left decimal flashes (until
reading is stable) for buffers
lower than first cal point
17. When the reading is stable (does not change by 0.01 pH in 10 seconds), the decimal point
will stop flashing. Press and hold the ENTER key to save the second SLOPE. The Model 60
will flash SAVE on the display along with SLP to indicate that the second slope value has
been saved.
SAVE
SLP
The system is now calibrated at three points and will return to normal operation.
18. Rinse the probe with deionized or distilled water.