Agilent Technologies 1147A User Manual page 15

• Immediately after powering on, this unit may be subject to an
NOTE
appreciable offset drift due to the effect of self- heating. To counteract
this, allow the unit to warm up for about 30 minutes before carrying
out measurement.
• When performing continuous measurements, it is necessary to be aware
that the zero offset voltage will drift if the ambient temperature
changes.
• Under certain circumstances, oscillation may occur if the probe is
connected to the AutoProbe interface while the Infiniium is on. This
does not indicate a malfunction. Oscillation can be stopped and
operation restored to normal by opening and closing the sensor head.
• At some frequencies, some sound may be produced by resonance, this
has no effect on measurements.
• Measurement accuracy is affected by the position of the conductor
being measured within the clamp aperture. The conductor should be
in the center of the clamp aperture.
• Before making a measurement, press the opening lever until the
"UNLOCK" indication disappears and check that the sensor head is
properly closed. If the sensor head is not properly closed, accurate
measurement will not be possible.
• Accurate measurement may be impossible in locations subject to strong
external magnetic fields, such as transformers and high- current
conductors, or in locations subject to strong external electric fields,
such as radio transmission equipment.
• At high frequencies, common mode noise may affect measurements
taken on the high voltage side of circuits. If this occurs, reduce the
frequency range of the waveform measuring instrument or clamp onto
the low- voltage side of the circuit (as shown in figure 5), as appropriate.
400
AC (f=50Hz)
DC
300
200
100
0
0 5
Figure 4. Typical probe consumption
10
Current to be measured [A]
15
15