Use this guide to better understand specifications, differences, and answer common questions about using your NI Digital Instrument, including NI Digital Waveform Instruments (High-Speed Digital I/O), NI Digital Pattern Instruments, and NI High-Speed Serial, terminal block or connector block accessories as signal breakouts. You will be guided through NI naming terminology, wiring considerations, signal mapping and pinouts, choosing the right accessory to meet your needs from low cost to high-performance noise reducing, shielded, and more.
This guide is intended to cover accessories designed for use with NI Digital devices, and their use cases. It does not cover use with other NI product families such as Switches, DAQ, C Series, or R Series, although some may use similar or the same accessories. It also does not cover legacy or End of Life (EOL) NI HSDIO accessories.
If you seek information about a specific connector block or terminal block, NI recommends that you first review this page and its more general information to better understand the product offerings, and then jump to the page for your specific model.
NI accessories come in a variety of shapes, orientations, features, and functionality. This section briefly explains what some of that terminology means. If you want to learn more about a specific accessory, visit the NI Digital Accessory Guide Page for your accessory, or its product page.
Use this section to better understand your NI accessory's model name and numbering.
Most SCB, CB, and TBX accessories typically follow the model prefix with a dash and a number indicating the number of pins on its connectors. Common Digital connectors are -68, and 68-pin connectors. Note that some connectors with the same pin count may come in different forms, such as the 68-pin VHDCI or SCSI.
Following the connector pin count, some accessories also include a suffix indicating additional information or functionality. Some of the more common used are:
These terms are used interchangeably in the context of NI accessories. These accessories act as a breakout box from the pins on your NI device, featuring screw terminals connectivity when wiring signals to your system.
For more information on replacement connectors for your NI HSDIO accessory, use the information found throughout this guide, as well as NI HSDIO Device Custom Cables, Replacement Connectors, and Screws.
When wiring your sensor or other signals into your NI accessory it is important to understand which screw terminal maps back to which terminals or pin numbers on your NI Digital Waveform Instruments, High-Speed Digital I/O, NI Digital Pattern Instruments, or NI High-Speed Serial device. Even if your accessory isn't covered in the extended information pages from this guide, this guidance generally applies to mapping any NI device's lines to its accessory.
If your device has extended information available in this guide, there may also be additional information on its Digital Accessory Guide page.
First, it is important to understand that each device may use its own pinout or pin mapping scheme. Some families of devices with the same pin count will use the same numbering and signal combinations, but others may not. There are several resources you can use to find this scheme.
Warning: Always refer to the product documentation for your specific device. Your device may use a completely different pin mapping than what is used in this example.
Navigate to the PXI-6541 entry in the NI-HSDIO Front Panel and Connector Pinout Help using one of the methods described above to find the following pinout diagram.
Figure 1: PXI-6541 Pinout with Pin 1 (DIO 31) and Pin 2 (GND) Highlighted
On our SCB-68 HSDIO we find terminal 1, to which we can wire our DIO31 signal wire to, and secure through the screw terminal. Similarly, we find terminal 2 to which we can wire our GND signal. In this example the pinout of the PXI-6541 aligns with the pin labels printed to the right of the screw terminals, however, this is not the case with all devices, an example of this can be found below. To ensure that you are properly wiring your device use the pin numbers on the circuit board.
Note: In the case of the SCB-68 HSDIO the pin number can be found on the opposite side of the screw terminal from the terminal name.
Figure 2: SCB-68A HSDIO with Terminals 1 and 2 Highlighted
Warning: Always refer to the product documentation for your specific device. Your device may use a completely different pin mapping than what is used in this example.
Navigate to the PXIe-6535 entry in the entry in the NI-DAQmx Device Terminals Help using one of the methods described above to find the following pinout diagram.
Figure 3: PXIe-6535 Pinout with Pin 65 (P0.0) and Pin 66 (GND) Highlighted
On our SCB-68 HSDIO we find terminal 65, to which we can wire our P0.0 signal wire to, and secure through the screw terminal. Similarly, we find terminal 66 to which we can wire our GND signal. In this example the terminal names of the PXIe-6535 do not align with the terminal labels printed to the right of the screw terminals. To ensure that you are properly wiring your device use the pin numbers on the circuit board.
Note: In the case of the SCB-68 HSDIO the pin number can be found on the opposite side of the screw terminal from the terminal name.
Figure 4: SCB-68A HSDIO with Terminals 65 and 66 Highlighted
The following table lists the most popular NI Digital accessories, and provides links to their Accessory Guide Page, if available. General compatibility with NI Digital devices, modules, and cables are listed on each Accessory Guide page, but a more extensive list can be found in the Digital Instrument Compatibility guide. For more information about an accessory not covered in this guide, review the accessory's manual.
Connectivity | Shielding | Product Page | Accessory Guide | Mounting |
---|---|---|---|---|
Screw Terminal | Shielded for high performance noise reduction | SCB-68 HSDIO | SCB-68 HSDIO | DIN Rail2 |
SCB-68A1 | SCB-68A | DIN Rail2 | ||
SCB-681 | SCB-68 | - | ||
Screw Terminal | Unshielded for low cost applications | CB-68LP | - | Custom Panel |
CB-68LPR | - | Custom Panel | ||
TBX-68 | - | DIN Rail | ||
SMA | Shielded for high performance noise reduction | SMA-2164 | - | - |
SMB | Shielded for high performance noise reduction | SMB-2163 | - | - |
Cable Adapter VHDCI-SCSI | N/A | 653x Cable Adapter | 653x Cable Adapter | - |
1The SCB-68 and SCB-68A must be configured in Direct Feedthrough Mode. For more information on how to configure these accessories in Direct Feedthrough mode see the SCB-68 and SCB-68A Accessory guide.
2DIN rail kit sold separately.