Source-Measure Concepts
5-25
The guard test lead IR drop is compensated for by connecting GUARD SENSE as shown in
Figure 5-14B. Sensing allows the guard voltage to be sensed (measured) at the resistor network
for better guard voltage regulation. If the remotely sensed guard voltage is less than the output
voltage of the SourceMeter, the guard voltage will be increased until the sensed guard voltage
equals the output HI voltage.
Note that in order to ensure that ohms guard current (I
G
) in Figure 5-14 does not exceed
50mA, output voltage from the SourceMeter must not exceed 5V (50mA
×
100
Ω
= 5V).
NOTE
For 6-wire ohms guard measurements, configure the output-off state to the GUARD
mode. For details on the GUARD output-off state, see Section 12, “Output
configuration.”
6430
x1
I-Source V-Meter
In/Out LO
In/Out HI
REMOTE
PreAmp
V,
Ω
GUARD
(Ohms Guard)
Guard
Ohms Guard Selected
I
G
I
L
HI (In/Out)
Guard (Cable)
LO (In/Out)
R
TL
Test Lead Resistance
1
Ω
10k
Ω
100k
Ω
20k
Ω
20k
Ω
10k
Ω
100k
Ω
I
G
I
L
R
TL
1
Ω
V,
Ω
GUARD
(Ohms Guard)
HI (In/Out)
Guard (Cable)
LO (In/Out)
6430
x1
I-Source V-Meter
In/Out LO
In/Out HI
REMOTE
PreAmp
Guard
Ohms Guard Selected
GUARD SENSE
-
+
A. Local Guard Sense
B. Remote Guard Sense
IN/OUT HIGH
IN/OUT HIGH
R
2
R
3
R
1
R
2
R
3
R
1
Figure 5-14
In-circuit ohms
measurements
using guard sense
Summary of Contents for 6430
Page 26: ......
Page 32: ......
Page 78: ...2 14 Connections ...
Page 98: ...3 20 Basic Source Measure Operation ...
Page 138: ...5 30 Source Measure Concepts ...
Page 156: ...6 18 Range Digits Speed and Filters ...
Page 168: ...7 12 Relative and Math ...
Page 176: ...8 8 Data Store ...
Page 202: ...9 26 Sweep Operation ...
Page 248: ...11 22 Limit Testing ...
Page 310: ...16 6 SCPI Signal Oriented Measurement Commands ...
Page 418: ...17 108 SCPI Command Reference ...
Page 450: ...18 32 Performance Verification ...
Page 477: ...A Specifications ...
Page 489: ...B StatusandErrorMessages ...
Page 498: ...B 10 Status and Error Messages ...
Page 499: ...C DataFlow ...
Page 503: ...D IEEE 488BusOverview ...
Page 518: ...D 16 IEEE 488 Bus Overview ...
Page 519: ...E IEEE 488andSCPI ConformanceInformation ...
Page 523: ...F MeasurementConsiderations ...
Page 539: ...G GPIB488 1Protocol ...
Page 557: ......