National Instruments SCXI: Part 3

This is the third part in our series about the National Instruments SCXI Series. There are several types of switches in the SCXI series. The first type is the Multiplexer/Matrix Switch Module. One of these Multiplexer/Matrix Modules is the SCXI-1127 (electromechanical relay). Another example is the SCXI-1128 (solid-state relay). Both are devices that function as multiplexer or matrix modules. As a multiplexer, they can operate in different multiplexing modes, such as 1-wire for resistive measurements including RTDs and low-resistance measurements. With the SCXI-1332 front-mounting terminal block, the SCXI-1127 and SCXI-1128 become a 4×8 2-wire matrix. Expanding the multiplexer or matrix channel count is as easy as adding additional modules.


The NI SCXI-1175 is a high-density multiplexer switch module. With 196 1-wire channels or 98 2-wire channels, the NI SCXI-1175 is capable of routing hundreds of signals to measurement devices or from source units. Each channel uses robust electromechanical relays and can switch up to 100 VDC/100 VAC or 1 A. With a scanning speed of up to 140 channels/s, the SCXI-1175 acts as an excellent front-end for high-channel-count automated test applications.

The National Instruments SCXI-1129 is a high-density matrix built to serve high-channel-count switching applications. The module is a 2-wire matrix, configurable with front mounting terminal blocks to achieve many different matrix configurations, including 4×64, 8×32, 16×16, dual 4×32, dual 8×16, and quad 4×16. For greater densities, matrix expansion is easily achievable with additional modules. Analog signals are passed between modules via a high-voltage backplane, a matrix expansion cable, and through analog plugs connecting terminal blocks, which virtually eliminate hours of complicated wiring. The NI SCXI-1129 is designed to work well with both low and high-voltage levels. For low-voltage measurements, the SCXI-1129 uses relays with low thermal offset to ensure accurate measurements. These same relays can handle up to 150 Vrms and 150 VDC.



The National Instruments SCXI-1130 is a high-density, multiconfiguration multiplexer/matrix switch module. This module is also a great choice for large or complex-channel-count systems. Multiplexer configurations include 256×1 (1-wire), 128×1 (2-wire), 64×1 (4-wire), or 16 banks of 16×1 (1-wire). Matrix configurations include 4×64 (1-wire), 8×32 (1-wire), or 4×32 (2-wire). These configurations are made available through the selection of an appropriate terminal block. Since this module has the speed of reed relays, the SCXI-1130 is an optimal front-end for high-speed measurement devices, such as the NI PXI-4070 6½-digit FlexDMM. However, for parallel operations requiring lower channel count, consider the NI PXI-2576.

The National Instruments SCXI-1166 is a general-purpose switch module with 32 channels. It has independent SPDT (Form C) nonlatching relays with low on-resistance and low thermal offset. The NI SCXI-1166 can switch up to 2 A at 30 VAC/30 VDC and can carry 5 A per channel. Hence, it is ideal for switching, routing, and controlling high-current signals. Each relay channel has a normally closed (NC), normally open (NO), and common (COM) terminal.

The National Instruments SCXI-1194 is a quad 4×1 high-frequency unterminated multiplexing switch capable of switching signals from DC to 2.5 GHz. The characteristic impedance of the channels on this module is 50 Ω. The NI SCXI-1194 has a maximum voltage rating of 30 Vrms with a maximum switching current of 500 mA. This module is perfect for applications that involve the routing of high-frequency signals inside automated test equipment systems since it has the capability to switch signals with low insertion loss. Furthermore, the astounding voltage standing-wave ratio (VSWR) and isolation parameters make this module the ideal solution in any system with high-frequency applications. The SCXI-1194 additionally features relay count tracking to aid in decreasing unforeseen system downtime.

The National Instruments SCXI-1195 is similar to the SCXI-1194 because it is also a quad 4×1 high-frequency unterminated multiplexing switch with similar specifications and features. Although, the NI SCXI-1195 can switch signals from DC to 5 GHz. The characteristic impedance of the channels on this module is 50 Ω. The NI SCXI-1195 has a maximum voltage rating of 30 Vrms with a maximum switching current of 500 mA.

The National Instruments SCXI-1190 is a general-purpose, quad 4×1 RF multiplexing switch for use in automated measurements. The NI SCXI-1190 uses single-pole double-throw high-bandwidth relays capable of switching signals from DC to 1.3 GHz. The characteristic impedance of the channels is 50 Ω. The maximum rated voltage of the switch is 30 VDC and the maximum rated current is 330 mA.

The National Instruments SCXI-1193 is a high-density 50 Ω RF relay module, which can be programmatically arranged in several ways: as an unterminated multiplexer, externally terminated multiplexer, or dimensionally versatile sparse matrix. Each configuration handles signal frequencies ranging from DC to more than 500 MHz. This one-slot switch module utilizes high-density push-on MCX connectors for manageable cabling. The NI SCXI-1193 module is created to be used with high-frequency instruments such as the NI PXI-5404 frequency generator and the NI PXI-5112 high-speed digitizer.


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