Gossen MetraWatt METRAOHM 413 Mode D'emploi page 22

4.3 Zero balancing
The METRAOHM 413 must be calibrated together
with the entire measurement line before each
measurement test series (see measurement setup
4.2). To take temperature changes into account, zero
balancing is also necessary if the same measurment
line is used again after a period of time.
Balancing occurs automatically for all measuring
ranges of 1μA ... 200 mA.
For balancing the device has to be switched off.
 Contact the test electrode of the METRAOHM
413 to the reference earth and ensure safe
contact.
 Press button
same time. The zero balance will be performed.
The display shows "CAL". After expiration of
time the value "0.00 ... 0.04 Ω" is indicated on
the display.
Attention!
Maintain contact as long as "CAL" is displayed
and the time expires.
If the message "Err" appears, zero balancing has
failed and must be repeated. This error occurs if the
test probe slips during balancing or if the measure-
ment line is too high-resistive (>3.5 Ω).
 For test purposes we recommend that the first
measurement always be made directly at the
reference earth (see section 4.4). The result
should be < 0.04 Ω for both polaritys.
Note: Long coiled measuring lines may cause faulty
measurments by their inductance. Resistance of the
measurement line remains in storage until a new
zero balance is performed. This value also remains in
storage if the measuring instrument is switched off,
or if the battery is replaced.
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and then the button at the