Fluke 8508A User Manual page 56

8508A
Users Manual
Internal Guard Connections
External Guard
front and rear panels are isolated from each other and from any internal connection. The
internal guard shields and tracks are connected directly to the internal 0 V.
External Guard
provides an Ohms Guard function. The internal guard shields, tracks, and the selected
front or rear Guard terminal are connected to the internal 0 V.
Selecting External Guard (ExGd)
See Figure 3-9 for connections when using the
To select
1. Press
2. Press the menu key ExGd to toggle the Multimeter's Guarding options.
The ExGd annunciator on the left-hand display indicates that External Guarding is
selected.
3-20
INPUT HI
SENSE HI
GUARD
SENSE LO
INPUT LO
Figure 3-9. Ω Guard Measurements
not selected: In the Ohms or PRT Functions the Guard terminals on the
selected: In the Ohms or PRT Functions selecting the External Guard
Guard terminal front
Front
External Guard
Internal Guard and External Guard
(OHMS and PRT)
Figure 3-10. Internal Guard Connections
:
External Guard
to enter the
Input key INPUT
Metal
Screen
SENSE HI INPUT HI
Rx
GUARD
SENSE LO
INPUT LO
Guard terminal rear
Rear
Internal Guard
External Guard
(DCV & I, ACV & I)
0 V
Ω Guard
menu.
INPUT Menu
Ra
Rb
Rg
Internal Guard
Shield and Tracks
feature.
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