National Instruments SCB-68 User Manual

DAQ

SCB-68 68-Pin Shielded Connector Block User Manual

SCB-68 Shielded Connector Block User Manual

December 2002 Edition

Part Number 320745B-01

Support

Worldwide Technical Support and Product Information

ni.com

National Instruments Corporate Headquarters

11500 North Mopac Expressway Austin, Texas 78759-3504 USA Tel: [phone]

Worldwide Offices

Australia 03 9879 5166, Austria 0662 45 79 90 0, Belgium 02 757 00 20, Brazil 55 11 3262 3599,
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Mexico 001 800 010 0793, Netherlands 0348 433466, New Zealand 09 914 0488, Norway 32 27 73 00,
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Slovenia 3 425 4200, South Africa 11 805 8197, Spain 91 640 0085, Sweden 08 587 895 00,
Switzerland 056 200 51 51, Taiwan 02 2528 7227, United Kingdom 01635 523545

For further support information, refer to the Technical Support and Professional Services appendix. To comment
on the documentation, send email to [e-mail].

© 1994–2002 National Instruments Corporation. All rights reserved.

Important Information

Warranty

The SCB-68 is warranted against defects in materials and workmanship for a period of one year from the date of shipment, as evidenced by
receipts or other documentation. National Instruments will, at its option, repair or replace equipment that proves to be defective during the
warranty period. This warranty includes parts and labor.

The media on which you receive National Instruments software are warranted not to fail to execute programming instructions, due to defects
in materials and workmanship, for a period of 90 days from date of shipment, as evidenced by receipts or other documentation. National
Instruments will, at its option, repair or replace software media that do not execute programming instructions if National Instruments receives
notice of such defects during the warranty period. National Instruments does not warrant that the operation of the software shall be
uninterrupted or error free.

A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside of the package before
any equipment will be accepted for warranty work. National Instruments will pay the shipping costs of returning to the owner parts which are
covered by warranty.

National Instruments believes that the information in this document is accurate. The document has been carefully reviewed for technical
accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to make changes to subsequent
editions of this document without prior notice to holders of this edition. The reader should consult National Instruments if errors are suspected.
In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it.

XCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS ANY WAR RANTY OF

E

MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE . CUSTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF

N

ATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER. NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR
DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE PO SSIBILITY
THEREOF. This limitation of the liability of National Instruments will apply regardless of the form of action, whether in contract or tort, including

negligence. Any action against National Instruments must be brought within one year after the cause of action accrues. National Instruments
shall not be liable for any delay in performance due to causes beyond its reasonable control. The warranty provided herein does not cover
damages, defects, malfunctions, or service failures caused by owner’s failure to follow the National Instruments installation, operation, or
maintenance instructions; owner’s modification of the product; owner’s abuse, misuse, or negligent acts; and power failure or surges, fire,
flood, accident, actions of third parties, or other events outside reasonable control.

Copyright

Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or mechanical, including photocopying,
recording, storing in an information retrieval system, or translating, in whole or in part, without the prior written consent of National
Instruments Corporation.

Trademarks

DAQCard™, National Instruments™, NI™, and ni.com™ are trademarks of National Instruments Corporation.

Product and company names mentioned herein are trademarks or trade names of their respective companies.

Patents

For patents covering National Instruments products, refer to the appropriate location: Help»Patents in your software, the patents.txt file
on your CD, or

ni.com/patents.

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

(1) NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF
RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN
ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT
INJURY TO A HUMAN.

(2) IN ANY APPLICATION, INCLUDING THE ABOVE, RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE
IMPAIRED BY ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY,
COMPUTER HARDWARE MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE FITNESS, FITNESS OF COMPILERS
AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION, INSTALLATION ERRORS, SOFTWARE AND
HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL
DEVICES, TRANSIENT FAILURES OF ELECTRONIC SYSTEMS (HARDWARE AND/OR SOFTWARE), UNANTICIPATED USES OR
MISUSES, OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER (ADVERSE FACTORS SUCH AS THESE ARE
HEREAFTER COLLECTIVELY TERMED “SYSTEM FAILURES”). ANY APPLICATION WHERE A SYSTEM FAILURE WOULD
CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH) SHOULD
NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE. TO AVOID
DAMAGE, INJURY, OR DEATH, THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO
PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT NOT LIMITED TO BACK-UP OR SHUT DOWN MECHANISMS.
BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS' TESTING
PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN
COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL
INSTRUMENTS, THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING
THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE
INCORPORATED IN A SYSTEM OR APPLICATION, INCLUDING, WITHOUT LIMITATION, THE APPROPRIATE DESIGN,
PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

Compliance

FFCC/Canada Radio Frequency Interference Compliance

Determining FCC Class

The Federal Communications Commission (FCC) has rules to protect wireless communications from interference. The FCC
places digital electronics into two classes. These classes are known as Class A (for use in industrial-commercial locations only)
or Class B (for use in residential or commercial locations). Depending on where it is operated, this product could be subject to
restrictions in the FCC rules. (In Canada, the Department of Communications (DOC), of Industry Canada, regulates wireless
interference in much the same way.)

Digital electronics emit weak signals during normal operation that can affect radio, television, or other wireless products. By
examining the product you purchased, you can determine the FCC Class and therefore which of the two FCC/DOC Warnings
apply in the following sections. (Some products may not be labeled at all for FCC; if so, the reader should then assume these are
Class A devices.)

FCC Class A products only display a simple warning statement of one paragraph in length regarding interference and undesired
operation. Most of our products are FCC Class A. The FCC rules have restrictions regarding the locations where FCC Class A
products can be operated.

FCC Class B products display either a FCC ID code, starting with the letters EXN,
or the FCC Class B compliance mark that appears as shown here on the right.

Consult the FCC Web site at

FCC/DOC Warnings

This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the instructions
in this manual and the CE Marking Declaration of Conformity*, may cause interference to radio and television reception.
Classification requirements are the same for the Federal Communications Commission (FCC) and the Canadian Department
of Communications (DOC).

Changes or modifications not expressly approved by National Instruments could void the user’s authority to operate the
equipment under the FCC Rules.

http://www.fcc.gov for more information.

Class A

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC
Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated
in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and
used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this
equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct
the interference at his own expense.

Canadian Department of Communications

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.

Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada.

Class B

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the
FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation.
This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not
occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can
be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of
the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

Canadian Department of Communications

This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada.

Compliance to EU Directives

Readers in the European Union (EU) must refer to the Manufacturer’s Declaration of Conformity (DoC) for information*
pertaining to the CE Marking compliance scheme. The Manufacturer includes a DoC for most every hardware product except
for those bought for OEMs, if also available from an original manufacturer that also markets in the EU, or where compliance is
not required as for electrically benign apparatus or cables.

To obtain the DoC for this product, click Declaration of Conformity at
by product family. Select the appropriate product family, followed by your product, and a link to the DoC appears in Adobe
Acrobat format. Click the Acrobat icon to download or read the DoC.

* The CE Marking Declaration of Conformity will contain important supplementary information and instructions for the user

or installer.

ni.com/hardref.nsf/. This Web site lists the DoCs

Contents

About This Manual

Conventions ...................................................................................................................xi

NI Documentation..........................................................................................................xii

Chapter 1
Introduction

What You Need to Get Started ...................................................................................... 1-1

Quick Reference Label .................................................................................................. 1-2

Installing Cables ............................................................................................................1-5

Using 68-Pin Cables ........................................................................................1-5

Using 100-Pin Cables ......................................................................................1-6

Configuring the SCB-68 ................................................................................................1-11

Safety Information ......................................................................................................... 1-11

Chapter 2
Parts Locator and Wiring Guide

Switch Configuration.....................................................................................................2-3

Chapter 3
Connecting Signals

Connecting Analog Input Signals .................................................................................. 3-1

Input Modes.....................................................................................................3-1

Nonreferenced or Floating Signal Sources......................................................3-3

Differential Inputs ............................................................................. 3-3

Single-Ended Inputs..........................................................................3-3

Ground-Referenced Signal Sources ................................................................3-4

Differential Inputs ............................................................................. 3-4

Single-Ended Inputs..........................................................................3-4

Differential Connection Considerations (DIFF Input Mode)..........................3-5

Differential Connections for Ground-Referenced Signal Sources.... 3-6

Differential Connections for Nonreferenced

or Floating Signal Sources .............................................................3-7

Using Bias Resistors...........................................................3-7

© National Instruments Corporation vii SCB-68 Shielded Connector Block User Manual

Contents

Single-Ended Connection Considerations ...................................................... 3-8

Single-Ended Connections for Floating Signal Sources

(RSE Input Mode).......................................................................... 3-9

Single-Ended Connections for Grounded Signal Sources

(NRSE Input Mode)....................................................................... 3-9

Connecting Analog Output Signals ............................................................................... 3-10

Connecting Digital Signals............................................................................................ 3-11

Connecting Timing Signals ........................................................................................... 3-12

Noise Considerations..................................................................................................... 3-13

Chapter 4
Using Thermocouples

Switch Settings and Temperature Sensor Configuration............................................... 4-2

Special Considerations .................................................................................................. 4-3

Chapter 5
Adding Components for Special Functions

Channel Pad Configurations.......................................................................................... 5-2

Conditioning Analog Input Channels ............................................................. 5-2

Conditioning Analog Output Channels........................................................... 5-3

Conditioning PFI0/TRIG1 .............................................................................. 5-4

Accuracy and Resolution Considerations...................................................................... 5-5

Open Thermocouple Detection...................................................................................... 5-5

Differential Open Thermocouple Detection ................................................... 5-6

Single-Ended Open Thermocouple Detection ................................................ 5-6

Sources of Error .............................................................................................. 5-6

Lowpass Filtering .......................................................................................................... 5-7

Theory of Operation........................................................................................ 5-7

One-Pole Lowpass RC Filter .......................................................................... 5-10

Selecting Components..................................................................................... 5-11

Adding Components ....................................................................................... 5-11

Single-Ended Lowpass Filter............................................................ 5-12

Differential Lowpass Filter............................................................... 5-12

Analog Output and Digital Input Lowpass Filtering ........................ 5-12

Lowpass Filtering Applications ...................................................................... 5-13

Noise Filtering .................................................................................. 5-13

Antialiasing Filtering ........................................................................ 5-13

Special Consideration for Analog Input Channels.......................................... 5-14

Special Consideration for Analog Output Signals .......................................... 5-14

Special Consideration for Digital Trigger Input Signals ................................ 5-15

Measuring a 4 to 20 mA Current................................................................................... 5-16

Theory of Operation........................................................................................ 5-16

SCB-68 Shielded Connector Block User Manual viii ni.com

Selecting a Resistor .........................................................................................5-17

Adding Components........................................................................................5-18

Attenuating Voltage....................................................................................................... 5-18

Theory of Operation ........................................................................................5-19

Selecting Components .....................................................................................5-20

Adding Components........................................................................................5-20

Special Considerations for Analog Input ........................................................5-22

Special Considerations for Analog Output......................................................5-23

Special Considerations for Digital Inputs........................................................5-24

Appendix A
Specifications

Appendix B

Contents

Single-Ended Inputs..........................................................................5-18

Differential Inputs ............................................................................. 5-18

Accuracy Considerations ..................................................................5-20

Single-Ended Input Attenuators........................................................ 5-20

Differential Input Attenuators...........................................................5-21

Analog Output and Digital Input Attenuators...................................5-22

Quick Reference Labels

Appendix C
Fuse and Power

Appendix D
SCB-68 Circuit Diagrams

Appendix E
Soldering and Desoldering on the SCB-68

Appendix F
Technical Support and Professional Services

Glossary

Index

© National Instruments Corporation ix SCB-68 Shielded Connector Block User Manual

About This Manual

This manual describes the SCB-68 and explains how to use the connector
block with National Instruments data acquisition (DAQ) devices.

Conventions

The following conventions appear in this manual:

<> Angle brackets that contain numbers separated by an ellipsis represent a

range of values associated with a bit or signal name—for example,
DIO<3..0>.

» The » symbol leads you through nested menu items and dialog box options

to a final action. The sequence File»Page Setup»Options directs you to
pull down the File menu, select the Page Setup item, and select Options
from the last dialog box.

This icon denotes a note, which alerts you to important information.

This icon denotes a caution, which advises you of precautions to take to
avoid injury, data loss, or a system crash. When this symbol is marked on
the device, refer to the Safety Information of Chapter 1, Introduction, for
precautions to take.

bold Bold text denotes items that you must select or click on in the software,

such as menu items and dialog box options. Bold text also denotes
parameter names.

italic Italic text denotes variables, emphasis, a cross reference, or an introduction

to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.

monospace Text in this font denotes text or characters that you should enter from the

keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames and extensions, and code excerpts.

© National Instruments Corporation xi SCB-68 Shielded Connector Block User Manual

About This Manual

NI Documentation

For more information about using the SCB-68 with DAQ devices, refer to

the following resources:

• DAQ device user manuals, at

• NI Developer Zone, at ni.com/zone

ni.com/manuals

SCB-68 Shielded Connector Block User Manual xii ni.com

Introduction

The SCB-68 is a shielded I/O connector block with 68 screw terminals for
easy signal connection to a National Instruments 68- or 100-pin DAQ
device. The SCB-68 features a general breadboard area for custom circuitry
and sockets for interchanging electrical components. These sockets or
component pads allow RC filtering, 4 to 20 mA current sensing, open
thermocouple detection, and voltage attenuation. The open component
pads allow signal conditioning to be easily added to the analog input (AI)
signals and to the DAC0OUT, DAC1OUT, and PFI0/TRIG1 signals of a
68-pin or 100-pin DAQ device.

What You Need to Get Started

To set up and use the SCB-68, you need the following items:

❑ SCB-68 68-pin shielded connector block

❑ One of the devices listed in Table 1-1

1

❑ One of the device-compatible cables listed in Table 1-1

❑ The device user manual or user guide, which you can access at

ni.com/manuals

❑ Phillips number 1 and number 2 screwdrivers

❑ 0.125 in. flathead screwdriver

❑ Long-nose pliers

❑ Wire cutters

❑ Wire insulation strippers

❑ Quick reference label for the DAQ device you are using

© National Instruments Corporation 1-1 SCB-68 Shielded Connector Block User Manual

Chapter 1 Introduction

❑ The following items, if you are adding components (optional):

– Soldering iron and solder

– Resistors

– Capacitors

Quick Reference Label

A quick reference label for E Series devices is included in this kit. Quick

reference labels for some other devices ship with the DAQ device itself.

These labels show the switch configurations and define the screw terminal

pinouts for compatible DAQ devices. You can put the label on the inside of

the SCB-68 cover for easy reference if you are using one of these devices.

Refer to Appendix B, Quick Reference Labels, for the switch

configurations and screw terminal pinouts that are included on each quick

reference label.

Table 1-1 shows cabling options and features for DAQ devices that are

compatible with the SCB-68. Figure 1-1 shows where to apply the quick

reference label to the inside cover of the SCB-68.

Table 1-1. Device-Specific Hardware Configuration

Device Cable Assembly Features

E Series Devices

68-Pin Devices (except DAQCards) SH68-68-EP,

SH68-68-R1-EP,
R6868

100-Pin Devices SH1006868 Direct feedthrough only

SCB-68 Shielded Connector Block User Manual 1-2 ni.com

Direct feedthrough only
Thermocouple measurements
Open thermocouple detection
Current input
Filtering
Voltage dividers
AC coupling

Thermocouple measurements
Open thermocouple detection
Current input
Filtering
Voltage dividers
AC coupling

Device Cable Assembly Features

NI 6024E for PCMCIA
(DAQCard-6024E),
NI 6036E for PCMCIA
(DAQCard-6036E),
NI 6062E for PCMCIA
(DAQCard-6062E)

Table 1-1. Device-Specific Hardware Configuration (Continued)

SCH68-68-EP,
RC68-68

Direct feedthrough only
Thermocouple measurements
Open thermocouple detection
Current input
Filtering
Voltage dividers
AC coupling

Chapter 1 Introduction

NI 6012E for PCMCIA
(DAQCard-AI-16XE-50),
NI 6041E for PCMCIA
(DAQCard-AI-16E-4)

NI 670X
for PCI/PXI/CompactPCI

NI 671X/673X
for PCI/PXI/CompactPCI

NI 6715 for PCMCIA
(DAQCard-6715)

NI 6533
for ISA/PCI/PXI/CompactPCI

NI 6533 for PCMCIA
(DAQCard-6533),

NI 6534
for PCI/PXI/CompactPCI

NI 7030/6030E
for PCI/PXI/CompactPCI,
NI 7030/6040E
for PCI/PXI/CompactPCI

NI 7030/6533
for PCI/PXI/CompactPCI

PSHR68-68,
PR68-68F

Analog Output (AO) Devices

SH68-68-D1
R6868

SH68-68-EP
SH68-68-R1-EP
R6868

SHC68-68-EP
RC6868

Digital I/O (DIO) Devices

SH68-68-D1
R6868

PSHR68-68-D1,
PR6868F

SH68-68-D1
R6868

Real-Time (RT) Devices

SH68-68-EP
SH68-68R1-EP,
R6868

SH68-68-D1
R6868

Direct feedthrough only
Thermocouple measurements
Open thermocouple detection
Current input
Filtering
Voltage dividers
AC coupling

Direct feedthrough only
RC filtering

Direct feedthrough only
RC filtering

Direct feedthrough only
RC filtering

Direct feedthrough only

Direct feedthrough only

Direct feedthrough only

Direct feedthrough only
Thermocouple measurements
Open thermocouple detection
Current input
Filtering
Voltage dividers
AC coupling

Direct feedthrough only

© National Instruments Corporation 1-3 SCB-68 Shielded Connector Block User Manual

Chapter 1 Introduction

Device Cable Assembly Features

Table 1-1. Device-Specific Hardware Configuration (Continued)

S Series Devices

NI 6110/6111 for PCI SH68-68-EP

NI 6115/6120
for PCI/PXI/CompactPCI

NI 6601/6602
for PCI/PXI/CompactPCI

NI 250X
for PXI/CompactPCI

NI 4350 for PCMCIA
(DAQCard-4350),
NI 4350 for USB

NI 4351
for PCI/PXI/CompactPCI

NI 445X for PCI SHC50-68 Direct feedthrough only

SH68-68R1-EP,
R6868

SH68-68-EP
SH68-68R1-EP,
R6868

Timing I/O (TIO) Devices

SH68-68-D1,
R6868

Other Devices

SH68-68 Direct feedthrough only

SH68-68 Not recommended for use with the

SH68-68 Not recommended for use with the

Direct feedthrough only

Direct feedthrough only

Direct feedthrough only

SCB-68

To maximize the available features,
NI recommends using this DAQ
device with the CB-68T, TBX-68,
or TBX-68T terminal blocks.

SCB-68

To maximize the available features,
NI recommends using this DAQ
device with the CB-68T, TBX-68,
or TBX-68T terminal blocks.

NI 455X for PCI SHC50-68 Direct feedthrough only

NI 5411
for PCI/PXI/CompactPCI

NI 5431
for PCI/PXI/CompactPCI

SCB-68 Shielded Connector Block User Manual 1-4 ni.com

SHC50-68 Direct feedthrough only

SHC50-68 Direct feedthrough only

Chapter 1 Introduction

1

2

3

10

9

1 Quick Reference Label
2 Cover
3 68-Pin Connector

Installing Cables

The following sections describe how to cable one or more SCB-68
connector blocks to a DAQ device using 68-pin or 100-pin cables.

Note For the I/O connector pinout of the DAQ device, refer to the device user manual at

ni.com/manuals or to the quick reference label provided with the DAQ device.

Using 68-Pin Cables

Table 1-1 lists the 68-pin cable assemblies that can connect the SCB-68 to
a 68-pin DAQ device. Each end of these 68-pin cables has a 68-pin I/O
connector that you can connect to the SCB-68 and to the 68-pin DAQ
device. In this configuration, the I/O connector pinout on the DAQ device
determines the I/O connector pinout on the SCB-68.

Screws

8

7

4 Lock Washers
5 Shielding Screws
6 68-Pin I/O Connector
7Base

Figure 1-1. SCB-68 Parts Locator Diagram

5

6

8 Strain-Relief Bars
9 Strain-Relief Screws
10 Circuit Card Assembly

4

© National Instruments Corporation 1-5 SCB-68 Shielded Connector Block User Manual

Chapter 1 Introduction

Figure 1-2 shows how to use a 68-pin cable to connect the SCB-68 to a

68-pin DAQ device.

1

5 4

1 68-Pin Cable Assembly
268-Pin DAQ Device
3 68-Pin I/O Connector

Using 100-Pin Cables

You can use the SH1006868 cable assembly to connect two SCB-68

connector blocks to a 100-pin DAQ device. The SH1006868 is Y-shaped,

with a 100-pin male connector on one end and two 68-pin female

connectors on the opposite end. The DAQ device connects to the 100-pin

cable connector, and an SCB-68 can connect to each 68-pin cable

connector. Figure 1-3 shows how use the SH1006868 to cable a 100-pin

DAQ device to two SCB-68 devices.

23

4 68-Pin I/O Connector
5 SCB-68 Connector Block

Figure 1-2. Connecting a 68-Pin DAQ Device to an SCB-68

SCB-68 Shielded Connector Block User Manual 1-6 ni.com

Chapter 1 Introduction

3

1

1 SCB-68 Connector Blocks
2 68-Pin I/O Connectors
3 SH1006868 Cable Assembly

When you attach two SCB-68 devices to the SH1006868 cable, one of the
SCB-68 connector blocks has a full 68-pin I/O connector pinout, and the
other SCB-68 connector block has an extended AI or extended digital
pinout. Each 68-pin end of the SH1006868 cable has a label that indicates
which I/O connector pinout is associated with that 68-pin I/O connector.

Figure 1-4 shows the pin assignments for the I/O connector on a 68-pin
E Series device. This connector is available when you use the SH68-68-EP
or R6868 cable assemblies with an E Series DAQ device. It is also one of
two 68-pin connectors available when you use the SH1006868 cable
assembly with a 100-pin E Series DAQ device.

2

5

4 100-Pin DAQ Device
5 100-Pin I/O Connector

4

Figure 1-3. Connecting a 100-Pin DAQ Device to Two SCB-68 Connector Blocks

© National Instruments Corporation 1-7 SCB-68 Shielded Connector Block User Manual

Chapter 1 Introduction

ACH8

ACH1

AIGND

ACH10

ACH3

AIGND

ACH4

AIGND

ACH13

ACH6

AIGND

ACH15

DAC0OUT
DAC1OUT

EXTREF

DIO4

DGND

DIO1

DIO6

DGND

+5V

DGND

DGND

PFI0/TRIG1

PFI1/TRIG2

DGND

+5V

DGND

PFI5/UPDATE*

PFI6/WFTRIG

DGND

PFI9/GPCTR0_GATE

GPCTR0_OUT

FREQ_OUT

1

1

3

34 68

33 67

32 66

31 65

30 64

29 63

28 62

27 61

26 60

25 59

24 58

23 57

22 56

21 55

20 54

19 53

18 52

17 51

16 50

15 49

14 48

13 47

12 46

11 45

10 44

943

842

741

640

539

438

337

236

135

ACH0
AIGND

ACH9

ACH2

AIGND

ACH11

AISENSE

ACH12

ACH5
AIGND
ACH14

ACH7

AIGND

AOGND

AOGND

2

2

DGND

DIO0

DIO5

DGND
DIO2

DIO7

DIO3

SCANCLK

EXTSTROBE*

DGND

PFI2/CONVERT*

PFI3/GPCTR1_SOURCE

PFI4/GPCTR1_GATE

GPCTR1_OUT
DGND

PFI7/STARTSCAN

PFI8/GPCTR0_SOURCE

DGND

DGND

1

No connect on the DAQCard-AI-16E-4, DAQCard-AI-16XE-50, NI PCI-6023E, NI PCI-6032E,
NI PCI-6033E, and NI PCI-6034E

2

No connect on the DAQCard-AI-16E-4 and DAQCard-AI-16XE-50

3

No connect on the DAQCard-AI-16E-4, DAQCard-AI-16XE-50, DAQCard-6024E, NI PCI-6023E,
NI PCI-6024E, NI PXI-6030E, NI PXI-6031E, NI PCI-6032E, NI PCI-6033E, NI PCI-6034E,
NI PCI-6035E, NI PCI-6036E, PCI-MIO-16XE-10, and PCI-MIO-16XE-50

Figure 1-4. SCB-68 E Series I/O Connector Pinout (Full)

SCB-68 Shielded Connector Block User Manual 1-8 ni.com

Chapter 1 Introduction

Figure 1-5 shows the pin assignments for the extended AI connector. This
pinout shows the other 68-pin connector when you use the SH1006868
cable assembly with an NI 6031E, NI 6033E, or NI 6071E.

ACH24
ACH17

ACH18

ACH27

ACH20
ACH21

ACH30

ACH23

ACH32
ACH41

ACH34
ACH35

AIGND

ACH44

ACH37

ACH38

ACH47

ACH48

ACH49
ACH58

ACH51

ACH52

ACH61

ACH54

ACH55

NC
NC

NC

NC

NC
NC

NC

NC

NC

34 68

33 67

32 66

31 65

30 64

29 63

28 62

27 61

26 60

25 59

24 58

23 57

22 56

21 55

20 54

19 53

18 52

17 51

16 50

15 49

14 48

13 47

12 46

11 45

10 44

943

842

741

640

539

438

337

236

135

ACH16
ACH25

ACH26

ACH19

ACH28

ACH29

ACH22

ACH31

ACH40
ACH33
ACH42

ACH43

AISENSE2

ACH36

ACH45

ACH46

ACH39

ACH56

ACH57
ACH50

ACH59

ACH60

ACH53

ACH62

ACH63

NC

NC

NC

NC
NC

NC

NC

NC

NC

NC = No Connect

Figure 1-5. SCB-68 E Series I/O Connector Pinout (Extended AI)

© National Instruments Corporation 1-9 SCB-68 Shielded Connector Block User Manual

Chapter 1 Introduction

Figure 1-6 shows the pin assignments for the extended digital connector.

This pinout shows the other 68-pin connector when you use the

SH1006868 cable assembly with an NI 6025E or the NI 6021E

(AT-MIO-16DE-10) for ISA.

34 68

GND

PC6

PC5

GND

PC3
PC2

GND

PC0

PB7

GND

PB5
PB4

GND
GND

PB1

PB0

GND

PA6

PA5

GND

PA3

PA2

GND

PA0

+5V

NC
NC

NC

NC

NC
NC

NC

NC

NC

33 67

32 66

31 65

30 64

29 63

28 62

27 61

26 60

25 59

24 58

23 57

22 56

21 55

20 54

19 53

18 52

17 51

16 50

15 49

14 48

13 47

12 46

11 45

10 44

943

842

741

640

539

438

337

236

135

PC7
GND

GND

PC4

GND

GND

PC1

GND

GND
PB6
GND

GND

PB3

PB2

GND

GND

PA7

GND

GND
PA4

GND

GND

PA1

GND

GND

NC

NC

NC

NC
NC

NC

NC

NC

NC

NC = No Connect

Figure 1-6. SCB-68 E Series I/O Connector Pinout (Extended Digital)

SCB-68 Shielded Connector Block User Manual 1-10 ni.com

Configuring the SCB-68

For instructions about using Measurement & Automation Explorer (MAX)
to configure the SCB-68 as an accessory for a DAQ device, complete the
following steps:

1. Navigate to MAX by selecting Start»Programs»National
Instruments»Measurement&Automation.

2. Select Help»Help Topics»NI-DAQ in MAX.

3. Select DAQ Devices»Configuring DAQ Devices»Configuring

DAQ Devices»Accessory in the Measurement & Automation Explorer
Help for MAX.

Safety Information

The following section contains important safety information that you must
follow when installing and using the SCB-68.

Do not operate the SCB-68 in a manner not specified in this document.
Misuse of the SCB-68 can result in a hazard. You can compromise the
safety protection built into the SCB-68 if the device is damaged in any way.
If the SCB-68 is damaged, return it to NI for repair.

Chapter 1 Introduction

Do not substitute parts or modify the SCB-68 except as described in this
document. Use the SCB-68 only with the chassis, modules, accessories,
and cables specified in the installation instructions. You must have all
covers and filler panels installed during operation of the SCB-68.

Do not operate the SCB-68 in an explosive atmosphere or where there may
be flammable gases or fumes. Operate the SCB-68 only at or below the
pollution degree stated in Appendix A, Specifications.

Pollution is foreign matter in a solid, liquid, or gaseous state that can reduce
dielectric strength or surface resistivity. The following is a description of
pollution degrees:

• Pollution Degree 1 means no pollution or only dry, nonconductive
pollution occurs. The pollution has no influence.

• Pollution Degree 2 means that only nonconductive pollution occurs in
most cases. Occasionally, however, a temporary conductivity caused
by condensation must be expected.

© National Instruments Corporation 1-11 SCB-68 Shielded Connector Block User Manual

Chapter 1 Introduction

• Pollution Degree 3 means that conductive pollution occurs, or dry,
nonconductive pollution occurs that becomes conductive due to
condensation.

Clean the SCB-68 with a soft nonmetallic brush. Make sure that the
SCB-68 is completely dry and free from contaminants before returning it
to service.

You must insulate signal connections for the maximum voltage for which
the SCB-68 is rated. Do not exceed the maximum ratings for the SCB-68.
Remove power from signal lines before connecting them to or
disconnecting them from the SCB-68.

Operate the SCB-68 only at or below the installation category stated in
Appendix A, Specifications.

The following is a description of installation categories:

• Installation Category I is for measurements performed on circuits not
directly connected to MAINS

1

. This category is a signal level such as
voltages on a printed wire board (PWB) on the secondary of an
isolation transformer.

Examples of Installation Category I are measurements on circuits not
derived from MAINS and specially protected (internal)
MAINS-derived circuits.

• Installation Category II is for measurements performed on circuits
directly connected to the low-voltage installation. This category refers
to local-level distribution such as that provided by a standard wall
outlet.

Examples of Installation Category II are measurements on household
appliances, portable tools, and similar equipment.

• Installation Category III is for measurements performed in the building
installation. This category is a distribution level referring to hardwired
equipment that does not rely on standard building insulation.

Examples of Installation Category III include measurements on
distribution circuits and circuit breakers. Other examples of
Installation Category III are wiring including cables, bus-bars,
junction boxes, switches, socket outlets in the building/fixed

1

MAINS is defined as the electricity supply system to which the equipment concerned is designed to be connected either for
powering the equipment or for measurement purposes.

SCB-68 Shielded Connector Block User Manual 1-12 ni.com

Chapter 1 Introduction

installation, and equipment for industrial use, such as stationary
motors with a permanent connection to the building/fixed installation.

• Installation Category IV is for measurements performed at the source
of the low-voltage (<1,000 V) installation.

Examples of Installation Category IV are electric meters, and
measurements on primary overcurrent protection devices and
ripple-control units.

Below is a diagram of a sample installation.

© National Instruments Corporation 1-13 SCB-68 Shielded Connector Block User Manual

Parts Locator and Wiring Guide

This chapter explains how to connect signals to the SCB-68.

The following cautions contain important safety information concerning
hazardous voltages and terminal blocks.

Cautions Keep away from live circuits. Do not remove equipment covers or shields unless

you are trained to do so. If signal wires are connected to the SCB-68, dangerous voltages
may exist even when the equipment is powered off. To avoid dangerous electrical shock,
do not perform procedures involving cover or shield removal unless you are qualified to do
so. Before you remove the cover, disconnect the AC power or any live circuits from the
SCB-68.

The chassis GND terminals are for grounding high-impedance sources such as floating
sources (1 mA maximum). Do not use these terminals as safety earth grounds.

Do not connect high voltages to the SCB-68 even with an attenuator circuit. Never connect
voltages ≥42 V
or connection.

. NI is not liable for any damage or injuries resulting from improper use

rms

2

© National Instruments Corporation 2-1 SCB-68 Shielded Connector Block User Manual

Chapter 2 Parts Locator and Wiring Guide

13

1

C6

R20
R21
C4

R22(A)

RC12(B)

RC4(E)

R23(C)

RC13(D)

R24(A)

RC14(B)

RC5(E)

R25(C)

RC15(D)

R26(A)

RC16(B)

RC6(E)

R27(C)

RC17(D)

R28(A)

RC18(B)

RC7(E)

R29(C)

C5

RC19(D)

R38

R30(A)

RC20(B)

RC8(E)

R31(C)

RC21(D)

R32(A)

RC22(B)

RC9(E)

R33(C)

RC23(D)

R34(A)

RC24(B)

RC10(E)

R35(C)

RC25(D)

R36(A)

RC26(B)

RC11(E)

R37(C)

RC27(D)

SCB-68

COPYRIGHT 1993

©

2

33

S4 S3

R4(F)

R5(G)

R6(F)

R7(G)

R8(F)

R9(G)

R10(F)

R11(G)

C3

R12(F)

R13(G)

R14(F)

R15(G)

R16(F)

R17(G)

R18(F)

R19(G)

34

68
34
67
33
66
32

65
31
64
30
63
29

62
28
61
27
60
26

59
25
58
24
57
23

S5

3 4

1

J1

3

C2

C1

12
46
13
47
14
48
15
49
16
50
17
51
18
52
19
53
20
54
21
55
22

RC2
R2

RC3

R3

RC1

R10

56

XF1

S1

S2

5

ASSY182470-01 REV.B

1

35

2

36

6

3

37

4

38

5

39

6

40

7

41

8

42

9

43

7

10
44
11
45

S/N

8

1 Pads R20 and R21
2 Switches S3, S4, and S5
3 68-Pin I/O Connector
4 Fuse (0.8 A)
5 Switches S1 and S2
6 Assembly Number and Revision Letter
7 Screw Terminals

101112

8 Serial Number
9 RC Filters and Attenuators for DAC0,

DAC1, and TRIG1
10 Breadboard Area
11 Temperature Sensor
12 Product Name
13 Pads for AI Conditioning

9

Figure 2-1. SCB-68 Printed Circuit Diagram

SCB-68 Shielded Connector Block User Manual 2-2 ni.com

Chapter 2 Parts Locator and Wiring Guide

To connect signals to the SCB-68, complete the following steps while
referring to Figure 1-1, SCB-68 Parts Locator Diagram, and to Figure 2-1.

1. Disconnect the 68-pin cable from the SCB-68, if it is connected.

2. Remove the shielding screws on either side of the top cover with a
Phillips-head number 1 screwdriver. You can now open the box.

3. Configure the switches and other options relative to the types of signals
you are using.

4. Loosen the strain-relief screws with a Phillips-head number 2
screwdriver. Slide the signal wires through the front panel strain-relief
opening. You can also remove the top strain-relief bar if you are
connecting many signals. Add insulation or padding if necessary.

5. Connect the wires to the screw terminals by stripping off 0.25 in. of the
insulation, inserting the wires into the green terminals, and tightening
the screws.

6. Reinstall the strain-relief bar (if you removed it) and tighten the
strain-relief screws.

7. Close the top cover.

8. Reinsert the shielding screws to ensure proper shielding.

You can now connect the SCB-68 to the 68-pin I/O connector.

Switch Configuration

The SCB-68 has five switches that must be properly configured to use the
SCB-68 with the DAQ device. Table 2-1 illustrates the available switch
configurations and the affected signals for each switch setting. Refer to
Table 2-1 to determine the switch setting that applies to your application,
and then refer to the following sections for more information on specific
types of signals.

© National Instruments Corporation 2-3 SCB-68 Shielded Connector Block User Manual

Chapter 2 Parts Locator and Wiring Guide

Table 2-1. Switch Configurations and Affected Signals

Switch Setting Applicable Signals

Temperature Sensor

S5 S4 S3

Signal Conditioning

Circuitry Power (Off)

S1

S2

Direct feedthrough, with temperature sensor disabled and
accessory power disabled

Temperature Sensor

S5 S4 S3

Signal Conditioning
Circuitry Power (On)

S1

S2

Analog input, analog output,
digital I/O, and timing I/O

Analog input
and analog output

1

Temperature sensor disabled, and accessory power enabled

2

Note: This configuration is the factory-default configuration.

SCB-68 Shielded Connector Block User Manual 2-4 ni.com

Table 2-1. Switch Configurations and Affected Signals (Continued)

Temperature Sensor

S5 S4 S3

Chapter 2 Parts Locator and Wiring Guide

Switch Setting Applicable Signals

Signal Conditioning

Circuitry Power (On)

S1

S2

Single-ended analog input

3

Single-ended temperature sensor, with accessory power enabled

Temperature Sensor

S5 S4 S3

Signal Conditioning

Circuitry Power (On)

S1

S2

Differential temperature sensor, with accessory power enabled

1

When accessory power is enabled, I/O pin 8 is fused and is intended to be connected to +5V. This setting is not
recommended for use with the NI 653X, NI 670X, or NI 660X. Refer to the device user manual at
determine if the device supplies +5 V to I/O pin 8.

2

Only applies to the signal conditioning circuitry.

3

Except NI 61XX devices. Refer to the device user manual at ni.com/manuals to determine if the device supports
single-ended inputs.

2

Differential analog input

2

ni.com/manuals to

© National Instruments Corporation 2-5 SCB-68 Shielded Connector Block User Manual

Connecting Signals

This chapter describes the types of signal sources that you use when
configuring the channels and making signal connections to the SCB-68,
describes input modes, and discusses noise considerations to help you
acquire accurate signals.

Connecting Analog Input Signals

The following sections describe how to connect signal sources for
single-ended or differential (DIFF) input mode. On most devices, you can
software-configure the DAQ device channels for two types of single-ended
connections—nonreferenced single-ended (NRSE) input mode and
referenced single-ended (RSE) mode. RSE input mode is used for floating
signal sources. In this case, the DAQ device provides the reference
ground point for the external signal. NRSE input mode is used for
ground-referenced signal sources. In this case, the external signal supplies
its own reference ground point, and the DAQ device should not supply one.

Note Some devices might only support one of the possible input modes.

3

Input Modes

You can configure the DAQ device for one of three input modes—NRSE,
RSE, or DIFF. The following sections discuss the use of single-ended and
differential measurements and considerations for measuring both floating
and ground-referenced signal sources. On devices that support both
single-ended and DIFF input modes, using DIFF input mode commits two
channels, ACH<i> and ACH<i+8>, to each signal. Figure 3-1 summarizes
the recommended input modes for both types of signal sources.

© National Instruments Corporation 3-1 SCB-68 Shielded Connector Block User Manual

Chapter 3 Connecting Signals

Signal Source Type

Input

Differential

(DIFF)

Single-Ended —

Ground

Referenced

(RSE)

Floating Signal Source

(Not Connected to Building Ground)

Examples:

• Ungrounded thermocouples

• Signal conditioning with
Isolated outputs

• Battery devices

Common-

Mode

Voltage

Refer to the

+

V

–

ACH(+)

1

ACH(–)

R

+
–

Using Bias Resistors

+

–

AIGND

section for information on bias resistors.

Common-

Mode

Voltage

+

V

–

ACH

1

AIGND

+
–

+

–

Grounded Signal Source

Examples:

• Plug-in instruments with
nonisolated outputs

ACH(+)

1

ACH(–)

Common-

Mode

Voltage

+

V

–

+
–

NOT RECOMMENDED

ACH

1

+ V

–

g

Common-

Mode

Voltage

+

V

–

+
–

Ground-loop losses, Vg, are added to

measured signal.

+

–

AIGND

+

–

AIGND

ACH

+

V

1

–

AISENSE

+

–

+

V

–

ACH

1

AISENSE

+

–

Single-Ended —

Nonreferenced

(NRSE)

Common-

Mode

Voltage

Refer to the

+
–

Using Bias Resistors

R

AIGND

Common-

Mode

Voltage

+
–

AIGND

section for information on bias resistors.

Figure 3-1. Summary of AI Connections

SCB-68 Shielded Connector Block User Manual 3-2 ni.com