Operation
pH 1970i
18
ba75690e01
01/2007
4.2.2
Measuring the pH value
AutoRead AR
(drift control) and hold
function
The AutoRead function (drift control) checks the stability of the mea-
surement signal. The stability has a considerable impact on the repro-
ducibility of the measured values. With the aid of the hold function the
measured value display is frozen.
Criterion
With identical measurement conditions, the following criterion is valid
for the AutoRead function:
Use the AutoRead function and hold function like this:
Note
The current AutoRead measurement can be terminated at any time
(accepting the current value) by pressing
<RUN/ENTER>
.
1
Perform the preparatory activities according to section 4.2.1.
2
Immerse the pH electrode in the test sample.
3
Press the
<M>
key repeatedly until
pH
appears on the status
display. The pH value appears on the display.
REL1
AR
1
LoBat
nLF
Lin
Oxi
Tref25
Tref20
Cal
TEC
ARng
Auto
Store
8
Time
Year
Ident
No.
Day.Month
Baud
Sal
cm
1/
K
/
%
RCL
REL2
pH
/
mV
m
cm
S/
%
mg/ l
Sal
O
S
pH
6
2 4 8
9 9
°
C
TP
Reproducibility
Response time
Better than 0.02
> 30 seconds
1
Call up the pH measuring mode with
<M>
and
<
▲
> <
▼
>
.
2
Activate the AutoRead function with
<AR>
.
The current measured value is frozen (hold function).
3
Start AutoRead with
<RUN/ENTER>
.
AR
flashes until a stable measured value is reached.
This measured value is transmitted to the interface.
4
If necessary, start the next AutoRead measurement with
<RUN/ENTER>
.
5
To terminate the AutoRead function: Press the
<AR>
key.
