Gossen MetraWatt METRAOHM 413 Mode D'emploi page 23

4.4 Measuring
Attention!
Measuring point must be free of voltage!
Button may only be pressed after establishing
contact to the measuring point if there is an absence
of voltage (see 4.5). Otherwise the device may be
damaged.
 If necessary, clean the measurement point from
corrosion or paint.
 Switch on the device with button
the green LED signalize that the device is ready
for measurement).
 Place the test electrode onto the measuring point
vertically if possible and assure safe contact.
If the red LED flashes and you hear an acoustic
warning signal, an external voltage is present!
The test must be interrupted (see 4.5).
Short warning signals can be caused by inductive
voltages or static charging which have no influence
on the measurement.
Note: Direction of current flow is indicated in the
display as "+" or "-". The displayed sign refers to the
test probe.
4.4.1 Standard measurements 0 - 2 MΩ
Tests with 200mA in accordance with EN/IEC 61557-4
can only be performed for resistance < 10 Ω and
must be performed with manual polarity change.
 Press button
ment. With measurement values <10 Ω the
METRAOHM 413 automatically switches to Lo-Ω
mode and continues measuring with a
measurement current of 200 mA (tests comply
with EN/IEC 61557-4 ).
The display shows the symbol „Lo-Ω" and the
right LED briefly signalizes the 200 mA
measurement current.
If the measurement value is out of measurement
range (>1999 kΩ) the symbol "OL" (Overflow)
appears on the display. The measurment result is
displayed for approx. 3 s, after this the display
changes to „+ Rdy".
 Change of polarity:
After measurement with positive polarity
(see above): press button
green LED display readiness for measurement
with different polarity). Perform measurements
with negative polarity in the same way.
Large deviations between values are an indication
for application of galvanic voltage. Repeat both
measurements. If the results deviate from each
other in a similar way than before, an average value
between the "+" and "-" may be assumed.
shortly to start the measure-
+/-
(+ Rdy and
("- Rdy" and
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