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National Instruments Corporation 1-1 NI 2501/2503 User Manual
1
Routing Signals with Your NI2501/2503
This manual describes the electrical and mechanical aspects of the
NI2501 FET multiplexer and the NI2503 mechanical relay multiplexer
and contains information concerning their installation andoperation.
This manual uses the term NI2501/2503 whenever information applies
to both instruments.

About the NI2501/2503

This section summarizes the features and operation of the NI2501/2503
switch card. Refer to Chapter2, NI2501/2503 Operation, for more
complete details. In addition, refer to AppendixA, Specifications,
fordetailed specifications of the two switch cards.
The NI2501 is a FET switch card, and the NI2503 is an armature
relayswitch card. Each consists of a 24 x 1 two-wire multiplexer in
PXI/Compact PCI format. You can take advantage of the switch card’s
flexibility to handle a wide variety of test systems through the use of
various accessories and software configurations. You can use the National
Instruments NI-SWITCH software included with your kit to configure and
operate the NI2501/2503 switch card.
The NI2501/2503 can also operate as two 12 x 1 or four 6 x 1 two-wire
multiplexers. You can use software-configurable switches to configure
theswitch card as a 48 x 1 one-wire multiplexer for making large numbers
of common referenced measurements. In addition, the NI2501/2503 can
operate as a 12 x 1 four-wire multiplexer to handle resistive measurements,
such as thermistors or RTDs. Finally, you can use a National Instruments
TB-2606 terminal block to further configure the NI2501/2503 as a 6 x 4
two-wire matrix.
The Connecting Signals section of this chapter contains more information
on one-wire, two-wire, four-wire, and matrix configurations, and includes
diagrams of the pinout connections to make.