Dual Independent Multiplexers; Connections And Wiring; Screw Terminals - Keithley 7701 User Manual

Dual independent multiplexers

WARNING Multiple channel operation should only be performed by experienced test engineers who
recognize the dangers associated with multiple channel closures.
Multiple channel operation ( ROUT:MULT:CLOS command) allows individual control of switching module channels. Multiple
channel operation allows the switching module to be configured as two independent multiplexers. The Model 7701 is normally
used as a single 1 × 32 multiplexer, but it can also be configured as two 1 × 16 multiplexers.
In Figure 1, the open position of channel 33 is shown. When channel 33 is closed, Multiplexer 1 (channels 1 through 16) are
isolated from Multiplexer 2 (channels 16 through 32).
For the dual multiplexer configuration, only Multiplexer 1 channels can be internally connected to the DMM of the
Model 27xx. Closing channel 35 allows channels 1 through 16 to be measured by the DMM.
When using the dual multiplexer configuration, Multiplexer 2 must be isolated from the sense terminals of the DMM. This can
be done by keeping channel 34 open, or by not installing the screw terminal jumpers to DMM Sense.

Connections and wiring

WARNING The following information is intended for qualified service personnel. Do not make
switching module connections unless qualified to do so.
To prevent electric shock that could result in serious injury or death, adhere to the
following safety precautions:
• Before removing or installing the switching module in the mainframe, make sure the
mainframe is turned off and disconnected from line power.
• Before making or breaking connections, make sure power is removed from all external
circuitry.
• Do not connect signals that may exceed the maximum specifications of the Model 7701.
Specifications are provided at the end of this section.
WARNING The Model 7701 is configurable to be connected to the internal DMM via the supplied
jumpers and the screw terminals. When connected to the internal DMM, all other
modules must be derated to 150VDC or 150Vrms (212V peak) for AC waveforms.

Screw terminals

The screw terminals of the Model 7701 are shown in
ing module channels to the DMM. User-configurable screw terminals are also provided to allow external input to bypass the
switching module channels.
Four jumpers are supplied with the Model 7701 for use with the screw terminals. As shown in
shipped with the jumpers not installed. With the jumpers not installed, all input to the Model 7701 is electrically isolated from
the DMM.
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Figure 2. As shown, screw terminals are provided to connect the switch-
Figure 2, the Model 7701 is