Advanced Measurement Technology 273A, Руководство пользователя

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Chapter 5—Operating Instructions 29
The +/- key reverses the polarity of the expression and can be pressed at any point
before [ENTER] is keyed.
b. To set and enter a Vertex Current of 1 mA when operating on the 100 mA range, key:
[E/I 2] [.] [0] [1] [ENTER]
Since the desired current (1 mA) is 1% of the selected Current Range (100 mA), E/I 1 is
set to ".01".
2. [DELAY 1] and [DELAY 2]: These keys are used to specify delay values. There are two
delays. The first, DELAY 1, precedes the scan. The second, DELAY 2, can be interposed
between the first and second legs of the scan. Delays can be specified as a time interval
(seconds) or as a drift rate (mV/s). Delays can also be PASS'ed, in which case the delay is
minimum (4 ms).
If specified as a time interval, the range is .1 s to 100,000 s, and the delay can be done with
the cell either ON or OFF. [CELL OFF], a key in the SETUP group, not to be confused with
[CELL ON] in the CELL group, determines whether the delay will be performed with the cell
ON or OFF. Each time the key is pressed, it toggles between the two setup states, as
indicated in the display. If the cell is OFF during the delay, no potential or current is applied.
If it is ON, potential or current, as appropriate, is applied.
If the intent is to postpone starting a scan until the open-circuit cell potential settles, the
delay is specified in mV/s. Typically, the potential drifts rapidly at first, and then more and
more slowly as it asymptotically approaches its final value. The delay will last as long as it
has to, measuring the potential all the time, until the drift rate drops below the specified
figure. Delay values from 0.001 mV/s to 10 mV/s can be set. Should the drift change
polarity, premature termination could occur. Drift-rate delays should always be done with the
Cell OFF. It is the user's responsibility to establish the required OFF state with the Scan
Setup CELL OFF key.
Note that the cell potential must be monitored for some time to acquire the data needed for
the driftrate calculation. Very low settings require long measurement times, up to a
maximum of 1000 s.
Once the delay interval ends, the scan begins and the potential (current), if not applied
during the delay, is applied. The Cell is ON during a scan, whatever its status during the
preceding delay.
Examples:
a. To set a Cell ON Delay 1 of 15 s, key:
[DELAY l] [1] [5] [SEC] [ENTER]
b. To set a Cell OFF Delay 2 of 0.1 s, key:
[DELAY 2] [0] [.] [1] [SEC] [CELL OFF] [ENTER]
c. To set a Delay 1 of .02 mV/sec, key:
[DELAY 1] [.] [0] [2] [mV / SEC] [ENTER]