17
3.7.4
DC Voltage Measurement 0-1000V Range
Use extreme care when working with high voltage circuits. Do not touch the In-
strument or test leads while power is on in the circuit being measured.
Before proceeding with the following steps, review the Safety Precautions in Para-
graph 3.2.
a.
Set the function switch at +DC.
b.
Set the range switch at the 250V/500V/1000V position.
c.
Plug the black test lead into the -COMMON jack and the red test lead into the
1000V jack.
d.
Make sure power is off in the circuit being measured and all capacitors are
discharged. Connect the black test lead to the negative side of the circuit
being measured and the red test lead to the positive side of the circuit.
e.
Turn on power in circuit being measured.
f.
Read the voltage using the 0-10 figures on the black scale marked DC. Mul-
tiply the reading by 100.
NOTE:
Turn off power to the circuit and wait until the meter indicates zero before
disconnecting the test leads.
3.8
AC Voltage Measurement
Branch and distribution circuits (120/240/480V etc.) can deliver dangerous explo-
sive power momentarily into a short circuit before the fuse/breaker opens the cir-
cuit. Make certain that the Instrument switches are set properly, jacks are con-
nected properly, and that the circuit power is turned off before making connections
to such circuits.
The 260 responds to the average value of an AC waveform. It is calibrated in
terms of the RMS value of a pure sine wave. If the waveform is nonsinusoidal,
depending on its waveform, the reading may be either higher or lower than the
true RMS value of the measured voltage. An error may be introduced if the 260 is
used to measure a nonsinusoidal waveform. Also, accuracy is lessened at higher
input frequencies (Figure 3-2).
3.8.1
AC Voltage Measurement 0-2.5 Thru 0-250V Range
Before proceeding with the following steps, review the Safety Precautions in Para-
graph 3.2.
a.
Set the function switch to AC volts only positions.
NOTE:
The meter will not indicate if the switch is incorrectly set to a DC position.
b.
Set the range switch at one of the five voltage range positions marked 2.5V,
10V, 25V, 50V or 250V. (When in doubt as to actual voltage present, always
use the highest voltage range as a protection to the Instrument. If the voltage
is within a lower range, the switch may be set for the lower range to obtain a
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Содержание 260-8XPI
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