Aci Ext Shunt (8588A Only) - Fluke 8588A Operator's Manual

8588A/8558A
Operators Manual
Measure DC Current with DCI Ext Shunt
The DCI Ext Shunt function provides a calculated current reading for a specified
current shunt by measuring the voltage across the shunt. If Shunt Corrections
are OFF, the displayed current is calculated from I = V/R where R is the
resistance of the shunt. If Corrections are ON, the displayed current is calculated
using the parallel resistance of the shunt and the 10 MΩ input impedance of the
DCI Ext Shunt function. Connections are straightforward, as shown in Figure 17.
Similar connection considerations are required for connecting the external shunt
input terminals as for dc current measurement. Use shielded twisted-pair cable to
reduce induced interference signals, and connect GUARD to the source of
common-mode voltage to provide a separate common-mode current path. To
connect the external shunt sense terminals to the Product, use low thermal leads
as in DCV.

ACI Ext Shunt (8588A Only)

The ACI Ext Shunt function measures the ac voltage across the shunt and shows
the calculated current, taking into account specific characteristics of the external
shunt. Push ,  (More), and then  (ACI Ext Shunt) to use the
ACI Ext Shunt function. With ACI Ext Shunt, the Product is used with an external
ac current shunt. If Shunt Corrections are OFF (under  (Measure Setup)),
the displayed current is calculated from I = V/R where R is the resistance of the
shunt. If Shunt Corrections are ON, the displayed current is calculated taking into
account the shunt AC-DC difference and the input impedance of the ACI Ext
Shunt function. The voltage can also be shown as a secondary reading. ACI Ext
Shunt augments the current measurement capability of the Product and is used
to calibrate current shunts themselves.
ACI Ext Shunt Menu
The section explains the ACI Ext Shunt menu.
 (Range): Allows selection of the Auto, 10 mV, 100 mV, 1 V, or 10 V ac
ranges. Auto autoranges between those ranges depending upon the input. The
input impedance is 10M Ohm in parallel with 80 pF. The internal firmware of the
Product calculates and corrects for shunt loading based on the 10 MΩ / 80 pF
input impedance if Shunt Correction is set to ON.
 (Resolution): The default resolution is 6 Digits. Other choices available
are 4, 5, and 7 Digits.
62
DCI Ext Shunt
UHF UHF
Voltage
F output F M
Figure 17. External DC Shunt Connection
Low Thermal Leads
HI
LO
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