Seaward DO5000 Series - Manual (Page 28)

Operating Instructions Microhmmeter Type DO5000
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5.4 Resistance measurement
The DO5000 should be in the measurement [STOP] mode. In this mode the measuring current
is switched off and the current terminals are shorted internally. Connect the measuring leads
as described in section 5.3 before starting the measurement select the current level and mode
required as described in section 4.2 WARNING the maximum measuring current is 10 Amps
on the lowest 3 measuring ranges ensure that the current level selected will not damage the
resistance being measured. Select the range required see 4.1 or auto range.
To start the measurement press the [MEAS] button the measured resistance value will be
displayed on the screen.
5.5 Resistance measurement with temperature compensation
Temperature compensation should be used when measuring the resistance of materials which
have a high temperature coefficient. Copper, for example, has a temperature coefficient of
0.3980%/K. The value of the resistance measured will therefore vary with the temperature of
the copper. To obtain consistent and meaningful results, the resistance values may be related
to a set ambient temperature, normally 20°C.
Example: Copper with a temperature coefficient of 3980ppm/k = 0.3980%/k
To measure with the temperature compensation, proceed as in 4.4 but in addition connect the
temperature sensor probe (see section 6 for accessories details and part numbers) to the front
panel socket. Select the temperature compensation measurement mode as described in 4.4.
Alternatively, if the ambient temperature is stable, a manual value may be entered, in this case
a temperature sensor is not required. The true measured resistance value will be displayed in
large digits on the DO5000 screen and the compensated value will be shown in smaller digits
below the main display. The measured or set temperature will also be shown.
Figure 5.5.1 Display screen temperature compensation mode
Temperature 20
qC 25qC 30qC 35qC
Resistance of Copper 18.000 m
: 18.358
m
: 18.716
m
: 19.075
m
:
% Increase in resistance 0% 1.99% 3.98% 5.97%
AUTO1: 30m
: 10.0A (AVE)
Slow
+ 18.358 m
:
T = + 25.00
qC (Ext)
RX = 18.000 m
: (Cu)
Meas Cont
TC