Tests: Noise rejection mode (DLRO2X)
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DLRO2 and DLRO2X
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9. Tests: Noise rejection mode (DLRO2X)
If the high noise indicator
appears on the display while using either the normal mode, long test lead mode or the
inductive mode, then the measurement is being affected by noise and the results may not be reliable. Noise can also
cause consecutive readings to vary significantly. The cause of this is usually from a noise current flowing through the
connection or joint being measured, or the induction of noise into the test leads. Interfering noise current will result
in measurements that are not repeatable, varying, out of specification and not useable.
To assist with this situation the DLRO2X is equipped with a
noise rejection test mode
. In this test mode the current
is passed continuously and in one direction only. The instrument then feeds a stream of measurements into our
patented Confidence Meter™. The measurement is then refined until a stable, accurate measurement is obtained.
All readings are displayed in mΩ.
Minimum current is 1 A.
Restricted to single tests.
In high noise mode, all soft keys are inactive.
The test is pre-set to single measurement, 1 A with previous 2 results displayed.
9.1 Confidence Meter™
1. If it is not possible to obtain a stable, accurate
measurement in the normal, long lead or inductive test
modes, turn the rotary switch to select the noise rejection
mode
Megger DLR02 icons
µΩ
µΩ
mΩ
, which will take a series of measurements and
feed them into the Confidence Meter™.
NOTE : To AUTO SAVE results click the
SAVE ( ) button
now (
Refer to 5. Data storage (DLRO2X only) on page 22).
2. Connect C1-C2 and P1-P2 to the instrument and the unit
under test. Proceed when both show green background
with
.
The test current applied will be continuous and up to 1A,
so for this reason the instrument will start the measurement
with a charging cycle similar to the inductive test mode.
The test current will then be increased as high as possible,
up to 1A.
3. To start the test press the TEST button.
Once the first measurements start to appear on the
display the Confidence Meter™ will start to operate.
At the top of the display two markers will indicate
the level of confidence the instrument has with the
measurement. Starting far apart at 0% confidence.
