Keithley 7711, Руководство пользователя

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4
Expansion
One Model 7711/7712 configuration is a dual (2 bank) 1
×
4 multiplexer. A single Model 7711/7712 module can also be
configured as a 4
×
4 blocking matrix. The 7711/7712 can be combined with additional modules to further expand its
multiplexing and matrix switching capabilities (specifications may degrade when the Model 7711/7712 is used in multiple
module configurations). Refer to
Table 1 for possible expansion information. Examples of multiplexer and blocking matrix
expansion follow Table 1 .
NOTE The commands in this section are formatted as follows: Command (@Model 27xx Slot #,
Channel #)
Multiplexer examples
NOTE To minimize noise within the system, terminate unused channels with 50
Ω
loads. If 50
Ω
loads are
not available, terminating unused connectors with a cable may also reduce noise within the
system.
Figure 2 shows how to create a 1
×
8 SP8T MUX (single-pole eight-throw multiplex) using two Model 7711 cards. Channels 1
and 2 are connected to OUT A and OUT B of the second card in slot two. Terminate unused channels (in the example, channels
3 and 4 on the Model 7712 in slot one) with a 50
Ω
load.
Figure 3 shows how to create a 1
×
12 MUX using two Model 7711 cards.
NOTE Channels 3 and 4 (of 7711 in slot 1) may also be connected to other banks that will create a 1
×
12
multiplexer (or a 1
×
16 multiplexer). See Figure 4 for a 1
×
12 example. The following is a list of
sample commands needed to operate the 1
×
8 multiplexer.
NOTE The command “ROUTe:MULTiple:CLOSe (@<channel list>)” closes one channel per bank (two
banks per Model 7711/7712 module), and opens all other channels within the same bank.
Table 1
Matrix and multiplex expansion
Multiplexer Blocking Matrix
Number of 7711/7712 Cards 1
××××
4 1
××××
8 1
××××
12 1
××××
16 4
××××
4 4
××××
8 4
××××
12 4
××××
16
1 X X
2 X X X X X
3 X X X X X* X X X
*Using four cards in a Model 2750, a 4
×
4 non-blocking matrix can be created (see the 4
×
4 non-blocking matrix example on page 9).