Facom 720.P30 Guía De Instrucciones página 11

OPERATION INSTRUCTION
1. For cosilloscope, insert the BNC connector into the CH1 terminal of any
oscilloscope with a minimum input impedance of 1MΩ. For automotive
uses, insert the supplied adapter into the BNC connector first and then
insert the " GND " plug of the adapter into the COM jack and the other
plug of the adapter into the V-Ω jack of any multimeter with a minimum
input impedance of 10MΩ.
2. If the current to be measured is an ac current, set the range switch in
30A range position. If the current to be measured is a dc current, set the
range switch in 30A range position.
The LED lights is a power indicator. If the LED does not light, the battery
is low and must be replaced immediately; otherwise measurement result
may be wrong.
3. During ac current measurement, the Current Probe will output an ac
voltage; and during dc current measurement, the Current Probe will
output a dc voltage.
Set the multimeter or oscilloscope in a correct function so that the mul-
timeter or oscilloscope will measure the output voltage of the Current
Probe properly and exactly during measurement.
Refer to the users manual of the multimeter or oscilloscope to obtain
the operation instructions of the multimeter or oscilloscope.
4. Before dc current measurement, adjust the zero adjustment thumbwheel
on the Current Probe until the Current Probe's output voltage ( which is
indicated on the display of the multimeter or oscilloscope ) equals zero.
Note: Ensure that the Current probe is away from any current carrying
conductor whilst the zero adjustment is made.
5. Press the trigger of the Current Probe and clamp the jaws around the
conductor to be tested. Make sure that the jaws are perfectly closed.
Note:
• Each time only one conductor should be clamped. Never clamp two or
more conductors.
• The conductor should be positioned in the center of the jaws and
should be perpendicular to the Current Probe.
6. Read the voltage reading on the display of the multimeter or oscillos-
cope.
Then calculate the current of the conductor by using the formula:
(In this formula,I is the current of the conductor, Reading is the voltage
reading on the display of the multimeter or oscilloscope, Sensitivity is the
output sensitivity of the Current Probe.)
Note
1. Do not apply voltage to the BNC connector or output terminals of the
Current Probe.
2. For dc current measurements, the display of the multimeter or oscil-
loscope will also indicate the measured current's direction. A positive
reading 7 indicates that the current direction is from the Current Probe's
front to its back. (Tip: Current direction is the opposite of electron flow
direction.)
3. When measuring dc current higher than 15A using this Current Probe,
zero the Current Probe and then perform measurement again if there
is a big difference between the readings of two consecutive measure-
ments.
4. In the case of dc current measurement, a hysteresis effect can occur so
that it is impossible to zero the Current Probe properly. To eliminate this
effect, open and close the jaws several times and turn the zero adjust-
ment thumbwheel.
Especially it is impossible to zero the Current Probe after having
inadvertently measured far more than 30A dc in the 30A dc range. In
this case, have the jaws clamp the conductor in the reverse direction in
order to zero the Current Probe properly.
NU-720.P30_0617 OK.indd 11
I = Reading
Sensitivity
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03/07/2017 11:52:24