18
GOSSEN-METRAWATT
to „–“ in line with the imprinted polarity symbols on the
front of the tester. Display of the left arrow signals the
ongoing measurement with opposite direction of the cur-
rent.
After a measurement cycle, the higher of the two measured
values is shown in digital form together with the word
„HOLD“. A brief sound signal draws your attention to the
end of the automatic measurement.
If the measured results for both current directions deviate
from each other by more than 10% – this corresponds to the
permissible service error – both measured values are dis-
played side by side with reduced resolution, e.g. as follows:
This presentation of the measured values informs you that
the measurement with automatic polarity reversal does not
give an unambiguous display, e.g. with a high contact
resistance at the contact points. In this case, measure the
resistance with manual polarity reversal according to the fol-
lowing description.
8.2
Measuring with manual polarity reversal
í
Briefly press the „
Ω→
“ pushbutton (3) or the „
Ω←
“ push-
button (4). You thus select the direction of the current
with which you want to measure.
í
Start measuring by pressing the measurement pushbut-
ton (8) in the probe (9) and hold the pushbutton at this
position. You may also start measuring by pressing the
measurement pushbutton „ “ (1) on the tester.
Now the measurement is made in the selected direction
of the current. You can recognize the direction on the
LCD display by the corresponding arrow next to the
„
Ω
character“.
The measured value is shown in both digital and analog
form. With measured values of more than 3.0
Ω
, the analog
indicator shows overrange. In this case, the triangle is
shown at the right end of the analog scale. The digital dis-
play shows measured values up to 30
Ω
.
„DATA“ and „HOLD“ function same as with ISO-
Ω
measure-
ment.
When the lamp in the probe (9) lights, it shows you that the
measured values are smaller than 0.3
Ω
(limit according to
DIN VDE). The lamp serves for a quick, optical continuity
test.
í
Now measure the resistance with reversed direction of
the current.