Fluke 5790B/3 Operator's Manual page 66

5790A
Operators Manual
In some applications the previous uncertainty may not meet your specific requirements.
Better uncertainties can be obtained by characterizing the A40 Current Shunt (with the
792A-7004 Adapter) for AC/DC current difference. This characterization can be done by
NIST or at our Fluke Standards Laboratory. At the Fluke Lab this characterization is
performed at specific currents and frequencies with present uncertainties as low a 100
ppm. Since the 792A-7004 Adapter is shunting part of the current, it must be sent in and
characterized with the A40 or A40A Current Shunts. When using the 5790A Shunt Input,
where the resistor is internal in the 5790A, the 5790A must be characterized with the A40
or A40A Current Shunts. Since this would tie up the entire 5790A Measurement Standard
for shunt characterization, it is recommended that for AC/DC current calibration where
better than standard uncertainties are needed, the 5790A with the 792A-7004 Adapter
should be used.
Current measurements are specified for transfer mode only. Use the ac/dc
difference specification for the voltage being read from the current shunt.
You supply a dc current reference to make a current transfer.
To use the SHUNT input, proceed as follows:
1. Connect the 5790A-7001 adapter to the SHUNT and INPUT 2 LO binding posts.
2. Connect a Model A40 or A40A Current Shunt to the adapter cable.
3. Connect the current shunt to the ac current source under test.
4. Press the [SHUNT] key so that its keycap indicator lights.
5. Select continuous trigger (EX TRIG keycap indicator off.)
6. The displays show relative readings up to 700 mV.
7. Apply the reference dc current to the current shunt and store the reference as
8. Reverse the polarity of the reference current and press the softkey to average the
9. Apply the ac current under test. Transfer results are continuously updated on the
To use the INPUT 1 and the 792A-7004 the adapter, proceed as follows:
1. Connect the 792A-7004 adapter to the INPUT 1 Type "N" connector.
4-18
Figure 4-4. Measuring Relative Current Using 792A-7004
described under "Instructions for Transfer Mode".
reference as described under "Instructions for Transfer Mode".
Control Display.
Note
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