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Note that up-ranging occurs at 105% of normal range and down-ranging occurs at 5% of normal range.
To cancel auto ranging, press
or
or
key. Pressing
to cancel auto ranging
leaves the instrument on the present range.
The
key has no effect on the continuity and diode test functions.
4.1.2 Relative
The relative operation could be used to null offsets or subtract a baseline reading from present and
future readings. When relative function is enabled, Model TH1941 uses the present reading as a relative
value. Subsequent readings will be the difference between the actual input value and the relative value.
You can define a relative value for each function. Once a relative value is set for a measurement function,
the value is the same for all ranges. For example, if 2V is set as a relative value on the 20V range, the
relative is also 2V on the 1000V, 100V, 1V or 100mV ranges.
Additionally, when you perform a ze
ro correction for DCV, Ω
measurements by enabling REL, the
displayed offset becomes the reference value. Subtracting the offset from the actual input zeroes the
display, as follows:
Displayed reading = Actual Input
–
Reference
Select a range that cannot accommodate the relative value does not cause an overflow condition, but it
also does not increase the maximum allowable input for that range. For example: on the 2V range,
Model TH1941 still overflows for a 2.1V input.
To set a REL value, press
Rel
when the display shows the value you want as the relative value. The
REL annunciator turns on. Press
Rel
a second time to disable REL.
4.1.3 Rate
The RATE operation sets the integration time of the A/D converter, the period of time the input signal is
measured. The integration time affects the usable digits, the amount of reading noise, as well as the
ultimate reading rate of the instrument.
In general, the fastest integration time (FAST set from the front panel or remote interface) results in
increased reading noise and fewer usable digits, while the slowest integration time provides the best
common-mode and normal-mode rejection. In-between settings are a compromise between speed and
noise.
The RATE parameters are explained as follows:
Fast
FAST sets speed to 25 readings per second. Use FAST, if speed is of primary importance, however it is
at the expense of increased reading noise and fewer usable digits.
Medium
Medium sets speed to 10 readings per second. Use Medium when a compromise between noise
