SCB-68 HSDIO : Digital Instrument Accessory Guide


This guide addresses many common questions for the SCB-68 HSDIO breakout connector or terminal blocks, which allow you to easily interface digital input and output signals. Whether you need mounting information, mappings or pinouts for wiring, or creating custom configuration this guide will provide a short summary, and then link to other resources like manuals, specifications, dimensional drawings, and more.


Using this Digital Accessory Guide

This guide is intended to cover the SCB-68 HSDIO 68-pin terminal block (PN 782914-01) that is designed for use with NI Digital and some R Series devices.  It does not cover the similar SCB-68 and SCB-68A terminal blocks.


Overview of the SCB-68 HSDIO

  • SCB-68 HSDIO provides a direct breakout of the terminals on the HSDIO or R Series device or module, using screw terminal connections. 
  • Upgraded design: magnetic lid, updated styling, and updated blue/silver color scheme.
    NI SCB-68A Shielded Connector Block
  • Smaller breadboard area, pinout for some HSDIO devices printed on breadboard.1 
  • Available pads to populate SMB connectors. 
  • DIN rail mounting options
  • Visually similar to SCB-68A, but functionally incompatible.

1The terminal names printed on the breadboard are only for the 654x devices. To ensure that you are wiring your device correctly, please reference the pin numbers printed on the breadboard.

Quick Specifications, Manuals, Quick Reference Labels, and Dimensional Drawings

This section contains a summary of information frequently sought when installing, wiring up or configuring the SCB-68 HSDIO.  More detailed information can be found in the linked additional resources below.  Dimensional drawings can be downloaded for free and are available in 2D and 3D formats; they contain size measurements and other helpful information, and are available in several popular formats, such as PDF, AutoCAD (.dxf, and .igs (IGES)), STEP (.stp), and .prt (Pro/E).


Connector and Pinout Information

68-pin 0.8 mm VHDCI (Receptacle)

Screw Terminal Wiring Specifications
Minimum wire gauge30 AWG
Maximum wire gauge14 AWG
Screw terminal torque0.5 to 0.6 N-m (4 to 5 in.⋅lb)
For more information, refer to the User Manual and Specifications
Physical Characteristics
Width14.7 cm (5.8 in.)
Depth14.7 cm (5.8 in.)
Height3.0 cm (1.2 in.)
Weight650 g (1 lb 7 oz)
For more information, refer to the User Manual and Specifications or Dimensional Drawing



Wiring Your SCB-68 HSDIO Terminal Block

To easily wire sensors and signals to your terminal block, leverage the published documentation and information in this guide. Here are the basic steps to designing your measurement circuit diagram, understanding pin mapping, connecting your wiring, and configuring your terminal block. Failure to set up your terminal block properly may lead to no readings, unexpected readings, noisy readings, or possible damage to your terminal block, device, or module.

  • The general concepts of pin mapping and pinouts are covered in the Digital Instrument Accessory Guide Main Page. Note, a common point of confusion for normal wiring is the need to first understand the cable mapping, or pinout at the connector found on your terminal block, which is not the case.
  • The Connection Guide and Specifications for the SCB-68 HSDIO are provided in the Quick Specifications and Published Resources section above. These contain pinout or pin mappings, guidance on how to populate the optional SMB Connectors, and also extended information for configuring your terminal block in the various modes that it supports, and extending its functionality.
  • It is also important to consider using shielded signal wires, shielded cables, and ensuring that the terminal block itself has been correctly grounded. NI recommends using 50 Ω cables for all signal connections. If you do not use 50 Ω cables, your application may be affected by signal reflections. You can limit the amplitude of signal reflections by terminating output lines with Schottky diodes. For more information terminating Output Lines with Schottky diodes see the Connection Guide provided in the Quick Specifications and Published Resources section above .
  • The breadboard on your SCB-68 HSDIO can be used to add SMB connectors  The Connection Guide referenced contains detailed information on when to do these setups, how to configure them, and other details like soldering and desoldering information.
  • Once you've completed your wiring, make sure to finish by tightening the strain relief bar to ensure that your wires can not easily pull out from your terminal block.


Mounting your SCB-68A


Compatible Devices, Modules, and Cabling for the SCB-68 HSDIO

Some devices and modules listed in the table have extended compatibility information, which is linked to in their Compatibility Guide. Refer to your device or module's user manual or user guide for more information.

Device or ModuleShielded CableUnshielded Cable
NI High-Speed Digital I/O (HSDIO) or Digital Waveform Instruments
NI 653x Models1See Compatibility Guide
NI 654x ModelsSee Compatibility Guide
NI 655x ModelsSee Compatibility Guide
NI Digital Pattern Instruments
PXie-6570See Compatibility Guide
NI High-Speed Serial Instruments
PXIe-6591See Compatibility Guide
NI R Series Models (NI 78xxR)
NI 782x ModelsSHC68-68-RDIO2N/A
NI 7845R/7846R/7847RSHC68-68-RDIO2N/A
NI 7855R/7856R/7857R/7858RSHC68-68-RDIO2N/A
NI 7861R/7862R/7867R/7868RSHC68-68-RDIO2N/A

1NI 6533/6534 Legacy High-Speed Digital I/O (HSDIO) are not supported. For compatible accessories see the Digital Instrument Cable and Accessory Guide



Was this information helpful?