Hanna Instruments HI 8614 - Manual (Page 6)

11 10
For other buffer temperatures, refer to page
13 for the appropriate mA / pH reading.
• Rinse the electrode with tap
water or distilled water and
a small amount of pH 4.01
or 10.01 buffer solution or
immerse it in the pH 4 rinse
solution (2nd calibration
point). Dip the electrode and
the temperature probe into
pH 4.01 (or 10.01) calibra-
tion buffer solution, shake
briefly and wait for a few
minutes for reading to stabi-
lize.
• Adjust the slope trimmer until the amme-
ter reads 8.58 mA or the display shows
"4.01" at 25°C. For other buffer tempera-
tures, refer to page 13 for the appropriate
mA / pH reading (HI 8614L).
If you are using pH 10.01
buffer solution adjust the
slope trimmer until the am-
meter read 15.43 mA at
25°C (77°F) or the value in-
dicated at page 13.
FOR HI 8614L ONLY
The Display Module is factory calibrated, so
that the LCD display results are referred to
the 4-20 mA loop current (e.g. LCD displays
0.00 pH when loop current is 4.00 mA and
displays 14.00 pH when current is 20.00 mA).
HI 7004
mA
mA
SLOPE ADJUSTMENT
OFFSET ADJUSTMENT
Procedure
• Disconnect the +ve supply cable from
"+VE LOOP" terminal and connect a 20mA
f.s. ammeter between the +ve cable and
"+VE LOOP" terminal.
• Remove the protective cap
from the electrode, rinse it
with some pH 7.01 solution
or immerse it in the pH 7
rinse solution, then immerse
the pH electrode and tem-
perature probe into pH 7.01
calibration buffer solution;
shake briefly and wait for
the reading to stabilize.
Note: the tip of the elec-
trode should be sub-
merged approximately
4 cm (1½") into the
solution. The tempera-
ture probe should be
located as close to
the pH electrode as
possible.
• Adjust the offset trimmer until the amme-
ter reads 12mA or the display shows "7.01"
(HI 8614L only) if the temperature of the
buffer is at 25°C.
HI 7007
4 cm
1½"
mA
SLOPE ADJUSTMENT
OFFSET ADJUSTMENT