Metrohm tiamo 1.2 Manual - Handbuch (Seite 413)

Commands 387
Note
You can use the switch-off time in the following way to calculate the maximum
stop drift to be used: the size of the last increment to be added depends on the
volume of the attached exchange unit. With a 20 mL exchange unit (10'000 pul-
ses per cylinder volume) – number of impulses depends on the dosing device –
the smallest possible increment is 2 µL. With a delay time of 5 s this means that
the last 2 µL of reagent to be added must be sufficient for 5 s or longer. This re-
sults in a drift of ≤ 2 µL/5 s ≤ 24 µL/min. The drift can be smaller than 24 µL/min
as we do not know whether the last increment would also have been sufficient
for 10 s. This means that if you have previously worked with a 20 mL exchange
unit (10'000 pulses per cylinder volume) and 5 s switch-off delay then you should
set a value of ≤ 24 µL/min as the stop drift.
Stop time
1 ... 999999 s (only Titrino)
The titration is stopped if the defined stop time has elapsed. This parameter
is only shown for
Stop criterion = time and Delay time = inf.
Endpoint 2
(only visible for EP1 at pH ≠ off )
[ on ], off
Switching endpoint 2 on/off. If this is deactivated all following parameters
are not visible.
EP2 at pH
-20.000 ... 20.000, [ off ] (Titrando),
-20.00 ... 20.00, [ off ] (Titrino)
Measured value for the second endpoint.
Parameters for endpoint 2 see above.
Titration parameters
Parameters defining the run of the titration.
Command name
25 characters, [ SET pH # ]
Name of the command.
Titration direction
Selection of the titration direction. If two endpoints are set the direction is al-
ready given and the following selection is ignored.
+
positive measured value alteration
[ - ]
negative measured value alteration
auto
The titration direction is determined automatically from the start measured
value and the set endpoint.