7.2 When the Device Appears to be a Problem
7-9 ZM2371/ZM2372
Table 7–1 When the device appears to be a problem 2/3
Large variations
of measured
value
Measurement speed is too
fast.
Reduce the measurement speed within allowable
range. If the averaging function is used together,
more precise speed can be set.
Signal level is too small.
Increase the signal level.
Measurement started before
the signal settles.
Make the trigger delay time longer.
Start the measurement after the contact
becomes stable and the signal settled.
The current cables and
voltage cables interfere with
each other (measured value
varies when the cables
move).
Twist the current cable to current cable, and the
voltage cable to voltage cable respectively to
reduce the mutual interference.
<Electrostatic induction> When high impedance
is measured, electrostatic-shield the L-side
signal wires appropriately. Exposed signal wires
cause the device to be affected by peripheral
potential variations. Also, ground the case and
peripheral conductors.
<Electromagnetic induction> Route the
connection cables so that a large loop is not
formed.
<Common impedance coupling> Do not ground
outer conductor of connection cables. If
grounded, noise current or a signal of adjacent
LCR meter will flow in, affecting the
measurement.
Signals interfere between
multiple LCR meters
With the triggered drive enabled, adjust the
trigger timing so that the measurement signals
of respective meters do not overlap temporally.
Two-terminal connection is
made
Make four-terminal connection. If low
impedance is measured with two-terminal
connection, contact resistance will have strong
effect. Do not connect between H
CUR
and H
POT
or
between L
CUR
and L
POT
in the middle of wiring.
Contact to DUT is unstable
Clean the contacts.
Turn on the contact check to check for
abnormality.
The contact resistance can be checked with
resistance value between H
CUR
and H
POT
or
between L
CUR
and L
POT
. The influence of contact
resistance can be checked by replacing a contact
point with known series resistance.
Measurement signal becomes
small due to damage of
measurement signal source
or defective connection cables
Check the magnitude of signal with a voltage
monitor or current monitor.
If discharge is made to measurement terminals,
the measurement signal source, voltage detector,
or current detector may be damaged.
Check the cables for disconnection, or the inner
and outer conductors for short-circuit.
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