Seaward DO4000 - Manual (Page 13)

Operating Instructions Digital Ohmmeter DO4000 Series
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9. Methods of Measurement
9.1 Ohmmeter Connections
The Digital Ohmmeter types 4000, 4001 and 4002 employ a four-wire method of
measurement, i.e. it is necessary to make four connections to the resistor under
test. The instrument is supplied with four leads terminated with small Kelvin clips.
a) Connect the Red leads to the +I and +U terminals, and the black leads
to terminals -I and -U. It is immaterial which leads of the pair goes to the
P or C terminals.
b) Clip on to the resistor under test fig. 8.2. Cleanliness is important and if
the sample is not clean, a rub with an abrasive paper to remove oxides
is recommended.
c) It is not always possible to use the combined current and potential clips,
in which case test leads with spade tags or special test fixtures may have
to be made for the user to suit particular applications.
d) Fig. 8.3 illustrates connections to various types of test resistors.
e) When measuring 4 terminal resistance standards, do not use the
combined current and potential probes, make four separate connections
to the current and potential terminals.
Fig. 8.2 Combined current and potential probes