Model 2701 User’s Manual
Close/Open Switching Module Channels
2-37
The 2-wire functions include DCV, ACV, DCI, ACI,
Ω
2, CONT, FREQ, PERIOD, and
TEMP (thermocouple and thermistor). The 4-wire functions/operations include
Ω
4, TEMP
(4-wire RTD), RATIO, and CH AVG (ratio and channel average are covered in Section 5).
With a 4-wire function/operation selected, channels are paired as follows:
Schematic diagram
The simplified schematic diagram of the Model 7700 is shown in Figure 2-12. Channels 1
through 20 are used for all measurements except amps. Channels 21 and 22 are used for
amps only.
There are two backplane relays (channels 24 and 25) to connect the input channel(s) to the
backplane of the Model 2701. With a 2-wire function (except amps) selected, channel 25
will close, and with a 4-wire function selected, both channels 24 and 25 will close.
There is a 2-pole/4-pole relay (channel 23) between channels 1 through 10 and channels
11 through 20. When a 2-wire function (i.e., DCV) is selected, channel 23 opens (2-pole
position) to allow any of the 20 channels to be connected to the input backplane.
When a 4-wire function is selected, channel 23 closes (4-pole position) to isolate channels
1 through 10 from channels 11 through 20. With a system channel (1 through 10) closed,
its paired channel (11 through 20) will also close to connect the sense channel to the sense
backplane.
For the two current channels (21 and 22), signal HI and LO are routed directly to the
backplane when the channel is closed.
As shown in Figure 2-12, there are also screw terminals labeled “Input,” “Sense,” and
“Amps.” The Input and Sense terminals are connected to the inputs of channels 24 and 25
(isolation relays). If channels 1 through 20 are not intended to be connected to the internal
DMM, channels 24 and 25 can be controlled independently using multiple channel
operation. The Amps terminals are connected directly to the DMM.
CH1 and CH11
CH6 and CH16
CH2 and CH12
CH7 and CH17
CH3 and CH13
CH8 and CH18
CH4 and CH14
CH9 and CH19
CH5 and CH15
CH10 and CH20
2701-900-01.book Page 37 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...
