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1693 RLC Digibridge
3.5.3 Settling Time or Programmed
Delay, in Triggered Measure
Mode
For accurate measurements, it is often helpful to
have a time delay between the START signal and the
beginning of the first voltage measurement within
the process of data conversion. Because such a delay
allows time for switching transients to settle, and
because more time is required for low test frequen-
cies, the Digibridge normally incorporates "settling
time" as follows.
• If measure mode is CONTINUOUS, settling
time = zero, programmed delay is disabled.
• If measure mode is TRIGGERED, with mea-
sure rate FAST, settling time = 7 ms/f
• If measure mode is TRIGGERED, with mea-
sure rate MEDIUM, settling time = 10 ms/f
• If measure mode is TRIGGERED, with mea-
sure rate SLOW, settling time = 12 ms/f,
where f is equal to the test frequency in kHz. NOTE:
the three times given above are verifiable in the
ENTER function by pressing [SHIFT][SPECIAL][4].
If measure mode is TRIGGERED, you can program
any desired delay (from 0 to 99999 milliseconds)
for transient voltages to settle, for mechanical han-
dling to be completed and contacts to settle, etc.
The Digibridge will pause for this much time after
each START signal, before actually starting to take
data. Any programmed delay replaces the default
"settling time"; and affects measurements only in
TRIGGERED measure mode.
For example, you can set delay to 25 ms by selecting
ENTER with the [FUNCTION] key and pressing [2]
[5)[=] [SHIFT][SPECIAL][4]
Programmed delay is typically required for measure-
ment of capacitors with bias, if the measure mode is
TRIGGERED. Refer to paragraph 3.7.
NOTE: In the CONTINUOUS measurement mode,
there will be no settling time or programmed delay;
the speed of the Digibridge makes it reasonable to dis-
regard the first displayed result (which is liable to be
46
in error for several reasons), and observe subsequent
displays for consistency, which indicates that any
transients have settled.
3.5.4 Measure Mode and Display
Selection, Effects on
Measurement Time
Measure Mode TRIGGERED. Selection of
TRIGGERED mode introduces a settling time or
delay between the START signal (which is necessary
in this mode) and the beginning of data acquisition.
Refer to paragraph 3.5.3, above.
Measure Mode CONTINUOUS. Selection of
CONTINUOUS measure mode eliminates the delay
described above. Notice that in continuous mode, the
measurement being mad e when the DUT is connected
to the Digibridge is erroneous. Subsequent measure-
ments have the benefit of any effective "delay" fur-
nished by the preceding ones.
Display Selection. The selection of BIN NO. display
cuts 6 to 10 ms from the measurement time, compared
to any other choice of display.
3.5.5 Integration-Time Factor (a
Special Function)
The length of time that the Digibridge spends in-
tegrating analog voltages in the process of data
acquisition can be varied by programming a number
called the "integration-time factor", if the measure
rate is selected to be FAST or MEDIUM. In general,
programming the I-T factor to a larger value allows
the Digibridge to integrate over more cycles of the
test signal , thus increasing the measurement time and
enhancing the accuracy. (If the measure rate is SLOW
integration time is automatically fixed at a relatively
large value, so that any programmed I-T factor has
no effect on measurement time.)
The I-T factor is normally 1. You can program it to
values in the range from 0.25 to 6. For I-T factor =
0.25, if measurement rate is FAST, the integration
time is set to 1 mS if the test frequency is above 1kHz,
or to one period of the test signal if test frequency is
Operation
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