How to Connect Signals to the PXI-2575 and SCXI-1175

Fig 1: PXI-2575 and SCXI-1175

The National Instruments PXI-2575 and SCXI-1175 are high-density multiplexer switch modules. With 196 1-wire channels or 98 2-wire channels, the NI PXI-2575 and NI SCXI-1175 are capable of routing hundreds of signals to measurement devices or from source units. Each channel uses robust electromechanical relays and is capable of switching up to 100 VDC/100 VAC or 1 A. With a scanning speed of up to 140 cycles/s, the PXI-2575 and the SCXI-1175 act as excellent front-ends for high-channel-count automated test applications.

There are two cabling options available for the PXI 2575 or SCXI-1175 available from National Instruments:

· SH200LFH-4xDB50F-S: LFH200 to 50-pin D-SUB Switch Cable (CH-CH Twisted), 1m
· SH200LFH- BAREWIRE: LFH200 Connector to Bare Wire Switch Cable, 2m

Fig 2: SH200LFH-4xDB50F-S cable

The SH200LFH-4xDB50F-S cable is recommended for connecting the PXI-2575 or SCXI-1175 to your system. One end of the cable terminates with an LFH200 connector. The other end of the cable terminates with four 50-pin female D-SUB connectors. The 50-pin female D-SUB connector is connected to a male 50-pin D-SUB terminal block which will be discussed in the terminal blocks section. For more instructions about the SH200LFH-4xDB50F-S cable, please refer to the LFH200 cable installation guide.

Fig 3: SH200LFH-BARE WIRE

The SH200LFH-BARE WIRE cable is recommended for connecting the switch module to your system if termination other than 50-pin female D-SUB is required. One end of the cable terminates with an LFH200 connector. The other end of the cable has eight bundles of 25 unterminated, tinned, and stripped cables. As shown in Fig 3, each cable leg has 25 wires. For more information about the SH200LFH-BAREWIRE cable, please refer to the LFH200 cable installation guide.

Fig 4: TBX-50 Terminal Reference

The NI TBX-50 or TBX-50B terminal blocks are DIN rail-mountable with screw terminals to connect the signals to the switch and includes a probe socket and a 50 pin D-SUB male connector. Using the cable options described above, connections are made between the four 50 pin terminal blocks TBX-50 and the PXI-2575/SCXI-1175. These terminal blocks can be used to access the terminals on your NI Switch. For more information on which pins correspond to each channel see the Installation Instructions for the DIN cable that you plan to use with your terminal block and NI Switch.

Using the SH200LFH-4xDB50F-S cable described described above, signal connections are made to screw terminals on a 50 pin terminal block from third party vendor. Terminal blocks from third party vendors are listed in the table below:

• Main Page: NI Switches Cable and Accessory Compatibility
• Multiplexer Switch Modules: Switches Cable and Accessory Compatibility
• LFH200 Cable Installation Instructions
• How to Connect Signals to an NI Switch
• NI Switch Mating Connectors for Custom Solutions or Cables