Tektronix Keithley KUSB-3108,KUSB-3102 User's Manual User manual
KUSB-3102 and KUSB-3108
User’s Manual
KUSB3102/8-900-01 Rev. A / January 2005
www.keithley.com
A GR
EATER MEASURE OF CONFIDENCE
WARRANTY
Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 3 years from
date of shipment.
Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries,
diskettes, and documentation.
During the warranty period, we will, at our option, either repair or replace any product that proves to be defective.
To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Cleveland, Ohio. You
will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service facility.
Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for the balance
of the original warranty period, or at least 90 days.
LIMITATION OF WARRANTY
This warranty does not apply to defects resulting from product modification without Keithley’s express written consent, or misuse
of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED
WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN
ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.
NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT,
INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE OF THE
POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO:
COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR
DAMAGE TO PROPERTY.
A G R E A T E R M E A S U R E O F C O N F I D E N C E
Keithley Instruments, Inc.
Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139
440-248-0400 • Fax: 440-248-6168 • 1-888-KEITHLEY (534-8453) • www.keithley.com
12/04
KUSB-3102 and KUSB-3108
User’s Manual
©2005, Keithley Instruments, Inc.
All rights reserved.
First Printing, January 2005
Cleveland, Ohio, U.S.A.
Document Number: KUSB3102/8-900-01A Rev. A
Manual Print History
The print history shown below lists the printing dates of all Revisions and Addenda created for this manual. The Revision Level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are released
between Revisions, contain important change information that the user should incorporate immediately into the manual.
Addenda are numbered sequentially. When a new Revision is created, all Addenda associated with the previous Revision
of the manual are incorporated into the new Revision of the manual. Each new Revision includes a revised copy of this
print history page.
Revision A (Document Number KUSB3102/8-900-01A)................................................................... January 2005
All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand and product names are trademarks or registered trademarks of their respective holders.
Safety Precautions
The following safety precautions should be observed before using
this product and any associated instrumentation. Although some instruments and accessories would normally be used with non-hazardous voltages, there are situations where hazardous conditions
may be present.
This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury. Read and follow all installation,
operation, and maintenance information carefully before using the
product. Refer to the manual for complete product specifications.
If the product is used in a manner not specified, the protection provided by the product may be impaired.
The types of product users are:
Responsible body is the individual or group responsible for the use
and maintenance of equipment, for ensuring that the equipment is
operated within its specifications and operating limits, and for ensuring that operators are adequately trained.
Operators use the product for its intended function. They must be
trained in electrical safety procedures and proper use of the instrument. They must be protected from electric shock and contact with
hazardous live circuits.
Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line voltage or replacing consumable materials. Maintenance procedures
are described in the manual. The procedures explicitly state if the
operator may perform them. Otherwise, they should be performed
only by service personnel.
Service personnel are trained to work on live circuits, and perform
safe installations and repairs of products. Only properly trained service personnel may perform installation and service procedures.
Keithley products are designed for use with electrical signals that
are rated Measurement Category I and Measurement Category II, as
described in the International Electrotechnical Commission (IEC)
Standard IEC 60664. Most measurement, control, and data I/O signals are Measurement Category I and must not be directly connected to mains voltage or to voltage sources with high transient overvoltages. Measurement Category II connections require protection
for high transient over-voltages often associated with local AC
mains connections. Assume all measurement, control, and data I/O
connections are for connection to Category I sources unless otherwise marked or described in the Manual.
Exercise extreme caution when a shock hazard is present. Lethal
voltage may be present on cable connector jacks or test fixtures.
The American National Standards Institute (ANSI) states that a
shock hazard exists when voltage levels greater than 30V RMS,
42.4V peak, or 60VDC are present. A good safety practice is to ex-
pect that hazardous voltage is present in any unknown circuit
before measuring.
Operators of this product must be protected from electric shock at
all times. The responsible body must ensure that operators are prevented access and/or insulated from every connection point. In
some cases, connections must be exposed to potential human contact. Product operators in these circumstances must be trained to
protect themselves from the risk of electric shock. If the circuit is
capable of operating at or above 1000 volts, no conductive part of
the circuit may be exposed.
Do not connect switching cards directly to unlimited power circuits.
They are intended to be used with impedance limited sources.
NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit
fault current and voltage to the card.
Before operating an instrument, make sure the line cord is connected to a properly grounded power receptacle. Inspect the connecting
cables, test leads, and jumpers for possible wear, cracks, or breaks
before each use.
When installing equipment where access to the main power cord is
restricted, such as rack mounting, a separate main input power disconnect device must be provided, in close proximity to the equipment and within easy reach of the operator.
For maximum safety, do not touch the product, test cables, or any
other instruments while power is applied to the circuit under test.
ALWAYS remove power from the entire test system and discharge
any capacitors before: connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal
changes, such as installing or removing jumpers.
Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Always
make measurements with dry hands while standing on a dry, insulated
surface capable of withstanding the voltage being measured.
The instrument and accessories must be used in accordance with its
specifications and operating instructions or the safety of the equipment may be impaired.
Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and operating information, and as shown on the instrument or test fixture panels, or
switching card.
When fuses are used in a product, replace with same type and rating
for continued protection against fire hazard.
Chassis connections must only be used as shield connections for
measuring circuits, NOT as safety earth ground connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use of a
lid interlock.
5/03
If a screw is present, connect it to safety earth ground using the
wire recommended in the user documentation.
!
The symbol on an instrument indicates that the user should refer to the operating instructions located in the manual.
The symbol on an instrument shows that it can source or measure 1000 volts or more, including the combined effect of normal
and common mode voltages. Use standard safety precautions to
avoid personal contact with these voltages.
The symbol indicates a connection terminal to the equipment
frame.
The WARNING heading in a manual explains dangers that might
result in personal injury or death. Always read the associated information very carefully before performing the indicated procedure.
The CAUTION heading in a manual explains hazards that could
damage the instrument. Such damage may invalidate the warranty.
Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and
all test cables.
To maintain protection from electric shock and fire, replacement
components in mains circuits, including the power transformer, test
leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses, with applicable national safety approvals,
may be used if the rating and type are the same. Other components
that are not safety related may be purchased from other suppliers as
long as they are equivalent to the original component. (Note that selected parts should be purchased only through Keithley Instruments
to maintain accuracy and functionality of the product.) If you are
unsure about the applicability of a replacement component, call a
Keithley Instruments office for information.
To clean an instrument, use a damp cloth or mild, water based
cleaner. Clean the exterior of the instrument only. Do not apply
cleaner directly to the instrument or allow liquids to enter or spill on
the instrument. Products that consist of a circuit board with no case
or chassis (e.g., data acquisition board for installation into a computer) should never require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected,
the board should be returned to the factory for proper cleaning/servicing.
Table of Contents
About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Intended Audience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
What You Should Learn from this Manual. . . . . . . . . . . . . . . . . . xi
Conventions Used in this Manual . . . . . . . . . . . . . . . . . . . . . . . . . xii
Related Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
Where To Get Help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
Chapter 1: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Supported Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Chapter 2: Principles of Operation . . . . . . . . . . . . . . . . . . . . 5
Analog Input Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Input Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Analog Input Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Specifying a Single Channel . . . . . . . . . . . . . . . . . . . . . . . 8
Specifying One or More Channels . . . . . . . . . . . . . . . . . . 9
Specifying Digital Input Lines in the Analog Input
Channel List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Performing Dynamic Digital Output Operations . . . . 10
Input Ranges and Gains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Specifying the Gain for a Single Channel . . . . . . . . . . . 13
Specifying the Gain for One or More Channels . . . . . . 13
A/D Sample Clock Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Internal A/D Sample Clock . . . . . . . . . . . . . . . . . . . . . . . 14
External A/D Sample Clock . . . . . . . . . . . . . . . . . . . . . . 15
Triggers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
vii
Contents
Analog Input Conversion Modes . . . . . . . . . . . . . . . . . . . . . . 16
Continuously Paced Scan Mode . . . . . . . . . . . . . . . . . . . 17
Triggered Scan Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Internally Retriggered Scan Mode . . . . . . . . . . . . . . 19
Externally Retriggered Scan Mode. . . . . . . . . . . . . . 21
Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Analog Output Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Output Resolution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Analog Output Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Output Ranges and Gains . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Conversion Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Digital I/O Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Digital I/O Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Resolution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Operation Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Counter/Timer Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
C/T Clock Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Internal C/T Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
External C/T Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Internally Cascaded Clock . . . . . . . . . . . . . . . . . . . . . . . . 37
Gate Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Pulse Output Types and Duty Cycles . . . . . . . . . . . . . . . . . . 39
Counter/Timer Operation Modes . . . . . . . . . . . . . . . . . . . . . 40
Event Counting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Frequency Measurement . . . . . . . . . . . . . . . . . . . . . . . . . 42
Rate Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
viii
One-Shot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Repetitive One-Shot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Chapter 3: Supported Device Driver Capabilities. . . . . . . . 53
Chapter 4: Programming Flowcharts. . . . . . . . . . . . . . . . . . 65
Single-Value Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Continuous A/D Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Event Counting Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Frequency Measurement Operations . . . . . . . . . . . . . . . . . . . . . . 73
Pulse Output Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Chapter 5: Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Running the Calibration Utility . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Calibrating the Analog Input Subsystem . . . . . . . . . . . . . . . . . . . 92
Configuring for Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Calibrating the Analog Input Circuitry . . . . . . . . . . . . . . . . . 93
Using the Auto-Calibration Procedure . . . . . . . . . . . . . 93
Using the Manual Calibration Procedure . . . . . . . . . . . 94
Calibrating the Thermocouple Circuitry . . . . . . . . . . . . . . . . 95
Calibrating the Analog Output Subsystem . . . . . . . . . . . . . . . . . 98
Contents
Chapter 6: Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . 101
General Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Service and Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Appendix A: Specifications . . . . . . . . . . . . . . . . . . . . . . . . 107
Appendix B: Connector Pin Assignments . . . . . . . . . . . . 117
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
ix
Contents
x
About this Manual
This manual describes the features of the KUSB-3102 and KUSB-3108
modules, the capabilities of the device driver, and how to program
these modules using DT-Open Layers™ software. Calibration and
troubleshooting information is also provided.
Intended Audience
This document is intended for engineers, scientists, technicians, or
others responsible for using and/or programming the KUSB-3102 or
KUSB-3108 modules for data acquisition operations in Microsoft®
Windows 2000 or Windows XP. It is assumed that you have some
familiarity with data acquisition principles and that you understand
your application.
What You Should Learn from this Manual
This manual provides detailed information about the features of the
KUSB-3102 and KUSB-3108 modules and the capabilities of the
device driver. The manual is organized as follows:
• Chapter 1, “Overview,” describes the major features of the
modules, as well as the supported software and accessories for
the modules.
• Chapter 2, “Principles of Operation,” describes all of the features
of the modules and how to use them in your application.
• Chapter 3, “Supported Device Driver Capabilities,” lists the data
acquisition subsystems and the associated features accessible
using the device driver.
xi
About this Manual
Conventions Used in this Manual
• Chapter 4, “Programming Flowcharts,” describes the processes
you must follow to program the subsystems on the KUSB-3102
and KUSB-3108 modules using DT-Open Layers-compliant
software.
• Chapter 5, “Calibration,” describes how to calibrate the analog
I/O circuitry of the modules.
• Chapter 6, “Troubleshooting,” provides information that you can
use to resolve problems with the modules and the device driver,
should they occur.
• Appendix A, “Specifications,” lists the specifications of the
modules.
• Appendix B, “Connector Pin Assignments,” shows the pin
assignments for the connectors and the screw terminal
assignments for the modules.
• An index completes this manual.
xii
The following conventions are used in this manual:
• Notes provide useful information or information that requires
special emphasis, cautions provide information to help you avoid
losing data or damaging your equipment, and warnings provide
information to help you avoid catastrophic damage to yourself or
your equipment.
• Items that you select or type are shown in bold.
Related Information
Refer to the following documents for more information on using the
KUSB-3102 or KUSB-3108 module:
• KUSB-3102 and KUSB-3108 User’s Manual provided with the
module. This manual describes the features of the KUSB-3102
and KUSB-3108 modules and device driver.
• DataAcq SDK User’s Manual. For programmers who are
developing their own application programs using the Microsoft
C compiler, this manual describes how to use the DT-Open
TM
Layers
access the capabilities of your module.
• DTx-EZ Getting Started Manual. This manual describes how to use
the ActiveX controls provided in DTx-EZ
capabilities of your module in Microsoft Visual Basic® or Visual
C++®.
• DT-LV Link Getting Started Manual. This manual describes how to
use DT-LV Link
language to access the capabilities of your module.
DataAcq SDKTM in Windows 2000 or Windows XP to
About this Manual
TM
to access the
TM
with the LabVIEW® graphical programming
• Microsoft Windows 2000 or Windows XP documentation.
• USB web site (http://www.usb.org).
• Omega Complete Temperature Measurement Handbook and
Encyclopedia®. This document, published by Omega Engineering,
provides information on how to linearize voltage values into
temperature readings for various thermocouple types.
Where To Get Help
Should you run into problems installing or using your KUSB-3102 or
KUSB-3108 module, please call the Keithley Technical Support
Department.
xiii
About this Manual
xiv
1
Overview
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Supported Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1
Chapter 1
Features
The KUSB-3102 and KUSB-3108 are low-cost, multifunction data
acquisition modules for the Universal Serial Bus (USB). Ta b le 1 lists
their key features.
Module
Analog Inputs
# of
Table 1: Key Features
Sample
Rate
# of Analog
Outputs
# of DIO
Lines
# of
Counter/
Timers
KUSB3102
KUSB3108
16 single-ended/ or
8 differential
16 single-ended/
8 differential/ or
7 thermocouples
and 1 CJC
100 kS/s 2 8 in,
8 out
50 kS/s 2 8 in,
8 out
2
2
The KUSB-3102 provides input gains of 1, 2, 4, and 8. The KUSB-3108
provides input gains of 1, 10, 100, and 500 to support thermocouples
and low-level analog input capability.
Both modules share the following major features:
• USB compatibility;
• Software configurable termination resistance for differential
inputs on a channel-by-channel basis.
• Continuously paced and triggered scan capability;
• A 32-location channel-gain list that supports sampling analog
input channels at the same or different gains in sequential or
random order;
• Internal and external clock sources for the analog input
subsystem;
2
• Digital TTL triggering for the analog input subsystem;
Overview
• One 8-bit digital input port and one 8-bit digital output port; the
digital input lines can be included as part of the analog input
channel-gain list to correlate the timing of analog and digital
events; digital outputs can drive external solid-state relays; and
• One dynamic digital output line;
• Two 16-bit user counter/timers programmable for event
counting, frequency measurement, rate generation (continuous
pulse output), one-shot, and repetitive-one shot pulse output
operations.
• Programmable gate types and pulse output types.
• Software calibration for the analog I/O subsystems.
1
1
1
1
1
1
1
1
1
3
Chapter 1
Supported Software
The following software is provided with the KUSB-3102 and
KUSB-3108 modules:
• Device Driver − This software must be installed and loaded
before you can use a KUSB-3102 and KUSB-3108 module with
any of the supported software packages or utilities.
• The Quick Data Acq application − This application provides a
quick way to get your module up and running. Using the Quick
Data Acq application, you can verify the features of the module,
display data on the screen, and save data to disk.
• Calibration Utility − This software allows you to calibrate the
analog I/O circuitry of the module. Refer to the KUSB-3102 and
KUSB-3108 User’s Manual for information on using this utility.
• DataAcq SDK − This DT-Open Layers Software Develop Kit
(SDK) allows programmers to develop application programs for
the KUSB-3102 and KUSB-3108 using the Microsoft C compiler in
Windows 2000 or Windows XP.
• DTx-EZ − This software package contains ActiveX controls that
allow Microsoft Visual Basic® or Visual C++® programmers to
access the capabilities of the KUSB-3102 and KUSB-3108
modules.
• DT-LV Link − This software package allows LabVIEW®
programmers to access the capabilities of the KUSB-3102 and
KUSB-3108 modules.
4
2
Principles of Operation
Analog Input Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Analog Output Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Digital I/O Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Counter/Timer Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5
Chapter 2
Figure 1 shows a block diagram of the KUSB-3102 and KUSB-3108
modules. Note that bold entries indicate signals you can access.
+5 V
D+
D−
Ground
USB
Interface
500 V Isolation Barrier *
Dynamic
Digital Out
Clock
Gate
Out
16 SE/8 DI
Analog
Inputs
Two 16-bit
User
Counter/Timers
8 Digital
Outputs
Analog Input
MUX
MicroController
High-Speed
Isolated Data Path
Isolated Side
Control Logic*
PGA
12- or 16-Bit
ADC
Isolated DC-DC
and Power Control*
Isolated
Powe r*
Channel Gain List
(32) Entries
Sample FIFO
10 kΩ Bias
Return
Termination
Resistors
8 Digital
Inputs
External
Clock and
Trigger Logic
Tri gger
Clock
12-or 16-Bit D/A
DAC0
DAC1
Figure 1: Block Diagram of the KUSB-3102 and KUSB-3108 Modules
6
Analog Input Features
This section describes the features of the analog input (A/D)
subsystem, including the following:
• Input resolution, described on this page;
• Analog input channels, described on page 7;
• Input ranges and gains, described on page 12;
Principles of Operation
2
2
• A/D sample clock sources, described on page 14;
• Analog input conversion modes, described on page 16;
• Triggers, described on page 16;
• Data formats, described on page 23;
• Data transfer, described on page 25; and
• Error conditions, described on page 26.
Input Resolution
The input resolution of the KUSB-3102 is 12-bits, while the input
resolution of the KUSB-3108 module is 16-bits. Note that the
resolution is fixed; it cannot be programmed in software.
Analog Input Channels
Both the KUSB-3102 and KUSB-3108 modules support 16
single-ended or pseudo-differential analog input channels, or eight
differential analog input channels.
2
2
2
2
2
2
In addition, the KUSB-3108 module provides a cold junction
compensation (CJC) circuit on channel 0 at 10 mV/
you can connect seven thermocouple inputs (in differential mode) to
the KUSB-3108 module.
° C. Using the CJC,
2
7
Chapter 2
You configure the channel type as single-ended or differential
through software. Using software, you can also select whether to use
10 kΩ termination resistance between the low side of each differential
channel and isolated analog ground. This feature is particularly
useful with floating signal sources. Refer to the KUSB-3102 and
KUSB-3108 Getting Started Manual for more information on wiring to
inputs and configuring the driver to use bias return termination
resistance.
Note: For pseudo-differential inputs, specify single-ended in
software; in this case, how you wire these signals determines the
configuration.
The KUSB-3102 and KUSB-3108 modules can acquire data from a
single analog input channel or from a group of analog input
channels. Channels are numbered 0 to 15 for single-ended and
pseudo-differential inputs, and 0 to 7 for differential inputs. The
following subsections describe how to specify the channels.
Specifying a Single Channel
The simplest way to acquire data from a single channel is to specify
the channel for a single-value analog input operation using software;
refer to page 16 for more information on single-value operations.
You can also specify a single channel using the analog input channel
list, described in the next section.
Note: If you want to perform a single-value digital input operation
while the A/D subsystem is configured, specify channel 16 (which
corresponds to the digital input port) in the A/D single-value
operation.
8
Specifying One or More Channels
Principles of Operation
You can read data from one or more analog input channels using an
analog input channel list. You can group the channels in the list
sequentially (starting either with 0 or with any other analog input
channel) or randomly. You can also specify a single channel or the
same channel more than once in the list.
Using software, specify the channels in the order you want to sample
them. You can enter up to 32 entries in the channel list. The channels
are read in order (using continuously paced scan mode or triggered
scan mode) from the first entry to the last entry in the channel list.
Refer to page 16 for more information on the supported conversion
modes.
Specifying Digital Input Lines in the Analog Input Channel List
In addition to the analog input channels, the KUSB-3102 and
KUSB-3108 modules allow you to read eight digital input lines (Port
A, lines 0 to 7) using the analog input channel list. This feature is
particularly useful when you want to correlate the timing of analog
and digital events.
2
2
2
2
2
2
To read these eight digital input lines, specify channel 16 in the
analog input channel list. You can enter channel 16 anywhere in the
list and can enter it more than once, if desired.
Note: If channel 16 is the only channel in the channel-gain list, the
module can read this channel at the maximum A/D sampling rate.
2
2
2
9
Chapter 2
The digital channel is treated like any other channel in the analog
input channel list; therefore, all the clocking, triggering, and
conversion modes supported for analog input channels are
supported for these digital input lines, if you specify them this way.
Performing Dynamic Digital Output Operations
Using software, you can enable a synchronous dynamic digital
output operation for the A/D subsystem. This feature is particularly
useful for synchronizing and controlling external equipment.
One dynamic digital output line (0) is provided (screw terminal 46).
This line is set to a value of 0 on power up; a reset does not affect the
values of the dynamic digital output line. Note that this line is
provided in addition to the other eight digital output lines; see page
32 for more information on the digital I/O features.
You specify the value (0 or 1) to write from the dynamic digital
output line using a digital channel list. A value of 0 indicates a
low-level signal; a value of 1 indicates a high-level signal.
10
The digital channel list corresponds to the analog input channel list.
As each entry in the analog input channel list is read, the
corresponding value you specified in the digital channel list is output
to the dynamic digital output line.
For example, assume that the analog input channel list contains
channels 0, 1, 2, and 3; that dynamic digital output operations are
enabled; and that the values in the digital channel list are 1, 0, 0, 1.
Figure 2 shows this configuration.
Principles of Operation
Analog
Channel List
0
1
2
3
Figure 2: An Example Using Dynamic Digital Outputs
As analog input channel 0 is read, a high-level signal is output to the
dynamic digital output line. As analog input channels 1 and 2 are
read, a low-level signal is output to the dynamic digital output line.
As analog input channel 3 is read, a high-level signal is output to the
dynamic digital output line.
On power up, a value of 0 is written to the dynamic digital output
line.
Digital
Channel List
1
0
0
1
Dynamic Digital
Output Line 0
1
0
0
1
2
2
2
2
2
2
2
2
2
11
Chapter 2
Input Ranges and Gains
Table 2 lists the supported gains and effective input ranges of the
KUSB-3102 and KUSB-3108 modules.
Table 2: Effective Input Ranges
Unipolar Input
Module Gain
KUSB-3102 1 0 to 10 V ±10 V
2 0 to 5 V ±5 V
4 0 to 2.5 V ±2.5 V
8 0 to 1.25 V ±1.25 V
KUSB-3108 1 − ±10 V
10 − ±1 V
100 − ±0.10 V
500 − ±0.020 V
Range
Bipolar Input
Range
Using software, specify 0 to 10 V for unipolar ranges or −10 V to +10 V
for bipolar ranges. Note that you specify the range for the entire
analog input subsystem, not the range per channel.
For each channel, choose the gain that has the smallest effective range
that includes the signal you want to measure. For example, if you are
using a KUSB-3102 and the range of your analog input signal is
±1.05 V, specify a range of −10 V to +10 V for the module and use a
gain of 8 for the channel; the effective input range for this channel is
then ±1.25 V, which provides the best sampling accuracy for that
channel.
12
The way you specify gain depends on how you specified the
channels, as described in the following subsections.
Principles of Operation
Note: For single-value operations, the KUSB-3108 module supports
autoranging, where the module determines the appropriate gain for
your range rather than you having to specify it. Refer to page 16 for
more information on using autoranging.
Specifying the Gain for a Single Channel
The simplest way to specify gain for a single channel is to specify the
gain for a single-value analog input operation using software; refer to
page 16 for more information on single-value operations.
You can also specify the gain for a single channel using an analog
input gain list, described in the next section.
Specifying the Gain for One or More Channels
For the KUSB-3102 and KUSB-3108 modules, you can specify the gain
for one or more analog input channels using an analog input gain list.
Using software, set up the gain list by specifying the gain for each
entry in the channel list. (The two lists together are often referred to
as the channel-gain list.)
2
2
2
2
2
2
For example, assume the analog input channel list contains three
entries: channels 5, 6, and 7; the gain list might look like this: 2, 4, 1,
where a gain of 2 corresponds to channel 5, a gain of 4 corresponds to
channel 6, and a gain of 1 corresponds to channel 7.
Note: For analog input channel 16 (the eight digital input lines) in
the channel list, specify a gain of 1 in the gain list.
2
2
2
13
Chapter 2
A/D Sample Clock Sources
The KUSB-3102 and KUSB-3108 modules allow you to use one of two
clock sources for pacing analog input operations in continuous mode:
• The internal A/D sample clock, which uses the 24-bit A/D
Counter on the module, or
• An external A/D sample clock, which you can connect directly to
the screw terminals on the module.
You use an A/D sample clock to pace the acquisition of each channel
in the channel-gain list; this clock is also called the A/D pacer clock.
Note: If you enter digital input channel 16 in the channel-gain list,
the A/D sample clock (internal or external) also paces the
acquisition of the eight digital input lines.
The following subsections describe the internal and external A/D
sample clocks in more detail.
14
Internal A/D Sample Clock
The internal A/D sample clock uses a 12 MHz time base.
Conversions start on the rising edge of the counter output; the output
pulse is active low.
Using software, specify the clock source as internal and the clock
frequency at which to pace the operation. The minimum frequency
supported is 0.75 Hz (0.75 Samples/s).
The maximum frequency of the KUSB-3102 module is
100 kSamples/s.
Principles of Operation
For the KUSB-3108 module, the maximum frequency is
50 kSamples/s for a single channel or a channel scan when the gain is
1 or 10. When the gain is 100, the maximum frequency is
10 kSamples/s. When the gain is 500, the maximum frequency is 2
kSamples/s.
2
According to sampling theory (Nyquist Theorem), specify a
frequency that is at least twice as fast as the input’s highest frequency
component. For example, to accurately sample a 20 kHz signal,
specify a sampling frequency of at least 40 kHz. Doing so avoids an
error condition called aliasing, in which high frequency input
components erroneously appear as lower frequencies after sampling.
External A/D Sample Clock
An external A/D sample clock is useful when you want to pace
acquisitions at rates not available with the internal A/D sample clock
or when you want to pace at uneven intervals.
Connect an external A/D sample clock to screw terminal TB25 on the
module (pin 25 on connector J1). Conversions start on the rising edge
of the external A/D sample clock input signal.
Using software, specify the clock source as external. The clock
frequency is always equal to the frequency of the external A/D
sample clock input signal that you connect to the module.
2
2
2
2
2
2
2
2
15
Chapter 2
Triggers
A trigger is an event that occurs based on a specified set of
conditions. KUSB-3102 and KUSB-3108 modules support the
following trigger sources:
• Software trigger − A software trigger event occurs when you start
the analog input operation (the computer issues a write to the
module to begin conversions). Using software, specify the trigger
source as a software trigger.
• External trigger − An external digital trigger event occurs when
the module detects a rising edge on the Ext A/D Trigger input
signal connected to screw terminal TB24 on the module (pin 24 of
connector J1). The trigger signal is TTL-compatible. Using
software, specify the trigger source as a external digital trigger
(external for DataAcq SDK users).
Analog Input Conversion Modes
The KUSB-3102 and KUSB-3108 modules support the following
conversion modes:
16
• Single-value operations are the simplest to use. Using software,
you can either specify the range, gain, and analog input channel,
or you can specify the range and analog input channel and have
the software determine the best gain for the range (called
autoranging). The board acquires the data from the specified
channel and returns the data immediately. Data can be returned
as both counts and voltage. For a single-value operation, you
cannot specify a clock source, trigger source, scan mode, or
buffer.
Single-value operations stop automatically when finished; you
cannot stop a single-value operation.
Loading...