Advanced Measurement Technology 273A, User Manual

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Chapter 5—Operating Instructions 31
and default values restored. Note that the effect is NOT the same as that which occurs when the
power is cycled. When the Model 273A powers down, all parameter values and selections are
retained. When it is powered up, most of the values in effect at the time that power shutdown
occurred are restored. The exceptions are the errors and SRQ, which are cleared by cycling the
power. (See Command Handbook for more information.)
FUNCTION 11, PRINT OUT INSTALLED OPTION: This function allows the user to determine at
a glance whether an option is installed in the unit. When accessed, the number corresponding to
the installed option is displayed. If a unit is equipped with the 273A/92 option, the number "92"
would be displayed.
FUNCTION 12, ENTER LOG REFERENCE: This function allows the user to specify the Current
Range for which a full-scale current will yield 0 V out in the LOG mode. When accessed, the
message ENTER LOG REFERENCE is displayed. At that point the user keys a number from "0"
(1 A range) to "-7" (100 nA range). The number keyed is the exponent if the current range were
expressed in engineering notation in units of amperes. The default value is "0" (1 A range).
For example, suppose one wished to specify the 1 µA range. The sequence would be:
1. Key [FUNCTION] [1] [2] [ENTER]. The message ENTER LOG REFERENCE will be
displayed.
2. Key [+/-] [6] [ENTER] to specify the 1 µA current range.
With this setting, a current of 1 µA will yield 0 V at the OUTPUT connector in LOG mode
operation.
FUNCTION 13, ENTER INTERRUPT: This function is used to specify the frequency with which
current interrupts are performed if operating with Current Interrupt IR Compensation with the
instrument under front-panel control. The interrupt period is specified in units of seconds from
.004 s to 30 s with the default corresponding to 1 s.
Example: To set a current interrupt period of one second, proceed as follows.
1. Key [FUNCTION] [1] [3] [ENTER]. The message ENTER IRUPT will be displayed.
2. Key [1] [ENTER] to specify an interrupt interval of one second.
FUNCTION 14, OUTPUT TIME CONSTANT: This function provides a digital, low-pass, 6
dB/octave filter at the front-panel OUTPUT connector. The time-constant range for the filter
extends from 0 to 30 seconds. The default value is "0."
FUNCTION 15, PEN DELAY: This function allows the user to control the pen-drop delay. When a
scan is initiated, the pen has to move to the starting coordinates. Should the pen drop during this
homing operation, the record will be marred. Function 15 determines when the pen will drop. The
range is 0 to 10 seconds and the default value is 0.5 seconds. The amount of delay required will
depend on the recorder.
FUNCTION 16, AUTO LIMIT: This function sets the most sensitive current range to which the
Model 273A can automatically range (auto-ranging active). The range is "0" (1 A) to -7 (100 nA).
The default value is "-6."
FUNCTI0N 17, CURRENT INTERRUPT PERCENT CORRECTION: This function sets the
percent of correction applied in Current Interrupt IR Compensation. The range is 0% to 200%.
The default value is 100%.