Model 2701 User’s Manual
Close/Open Switching Module Channels
2-9
4-wire functions (paired channels)
A 4-wire function, such as
Ω
4, requires that another measurement channel be paired to the
system channel. For example, if the switching module has 20 measurement channels,
channels 1 through 10 can be used as the system channel, while channels 11 through 20
are used as the paired channel. For a switching module that has 20 measurement channels,
channel 1 is paired to channel 11, channel 2 is paired to channel 12, channel 3 is paired to
channel 13, and so on.
Figure 2-2 shows an example of system channel connections for a 4-wire function.
Assume a Model 7700 switching module is installed in slot 1 of the mainframe, and a
4-wire function, such as
Ω
4, is selected. When channel 101 is closed using the system
channel close keys, the Channel 1 relay and the input backplane isolation relay
(Channel 25) closes to connect the channel to DMM Input. Also, the Channel 11 relay and
the sense backplane isolation relay (Channel 24) close to connect the paired channel to
DMM Sense. Also, note in Figure 2-2 that the Channel 23 relay closes to isolate channel 1
from channel 11.
The complete simplified schematic of Model 7700 is provided in Figure 2-12.
Figure 2-2
4-wire system channel connections to Model 2701 DMM
DMM
Model 7700 Switching Module
Model 2701
Slot 1
Close channel 101
System channel operation:
(closed position
shown
)
Channel 1
Relay
HI
LO
HI
LO
Input
Channel 25
Backplane
Isolation
Relay
Channel 1
Channel 11
Relay
HI
LO
HI
LO
Sense
Channel 24
Backplane
Isolation
Relay
Channel 11
Channel
23
2-Pole/4-Pole
Relay
2701-900-01.book Page 9 Wednesday, August 3, 2011 9:43 AM
Summary of Contents for 2701
Page 344: ...12 CommonCommands 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 366: ...15 SCPIReferenceTables 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 393: ...A Specifications 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 399: ...B Model7700ConnectionGuide 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 410: ...C StatusandErrorMessages 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 417: ...D SignalProcessing SequenceandDataFlow 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 430: ...E MeasurementConsiderations 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 450: ...G KE2700InstrumentDriver Examples 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...