Hanna Instruments HI 8510 - Manual (Page 20)

39
38£
38
ORP DIAGNOSTIC TESTS
HI 8512 and HI 8720 are ORP controllers
provided with autodiagnostic functions that
allow to check and troubleshoot any
malfunctioning.
The functions are made via front panel keys
to isolate the cause of malfunction.
For HI 8720 only, press
MEASURE key before
proceeding with the following
tests.
A) 0 mV Test
Press the 0 mV TEST
key and the display
should show a value of
0±10 mV, to verify the
"zero" calibration of the
instrument.
B) 500 mV Test
Press the 500 mV TEST
key and the display should
show a value of 500±20
mV, to verify the slope
at 500 mV.
COARSE
SET
FINE
MEA
SURE
0 mV
TEST
500 mV
TEST
mV
0 mV
TEST
500 mV
TEST
mV
B) Internal Offset Circuit Test
Press the pH7 TEST key and the display
should show a value within 7±1 pH, to
verify the internal circuit of the meter in
terms of the offset compensation.
C) Amplifier Circuit Test
Press the pH4 TEST key and the display
should show a value within the 3.30 to
4.30 pH range, to verify the amplifier circuit
of the meter.
pH
pH 7
TEST
pH 4
TEST
pH