NI PXI-4204 User manual

PXI
NI PXI-4204 User Manual
NI PXI-4204 User Manual
June 2007
373529C-01

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The NI PXI-4204 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.
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will, at its option, repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects
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Conventions
The following conventions are used 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,
AO <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 a
product, refer to the Read Me First: Safety and Radio-Frequency
Interference for information about precautions to take.
When symbol is marked on a product, it denotes a warning advising you to
take precautions to avoid electrical shock.
When symbol is marked on a product, it denotes a component that may be
hot. Touching this component may result in bodily injury.
bold Bold text denotes items that you must select or click 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. Italic text 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.

©National Instruments Corporation v NI PXI-4204 User Manual
Contents
Chapter 1
About the NI PXI-4204
What You Need to Get Started ......................................................................................1-2
National Instruments Documentation ............................................................................1-2
Installing the Application Software, NI-DAQ, and the DAQ Device ...........................1-3
Installing the NI PXI-4204 ............................................................................................1-3
LED Pattern Descriptions ..............................................................................................1-4
Chapter 2
Connecting Signals
Connecting Signals to the NI PXI-4204 ........................................................................2-1
Front Signal Connector....................................................................................2-3
Analog Input Connections...............................................................................2-5
Floating Signal Source Connection...................................................2-6
Shielded Floating Signal Source Connection (Recommended) ........2-7
Ground-Referenced Signal Connection ............................................2-8
Shielded Ground-Referenced
Signal Connection (Recommended) ..............................................2-9
Alternative Shielded Ground-Referenced Connection .......2-10
High CMV Connection .....................................................................2-11
Shielded High CMV Connection ......................................................2-12
Chapter 3
Using the NI PXI-4204
Theory of Operation.......................................................................................................3-1
Signal Conditioning Functional Overview......................................................3-3
Measurement Considerations ..........................................................................3-4
Differential Signals ...........................................................................3-4
Input Impedance................................................................................3-5
Common-Mode Rejection Ratio .......................................................3-5
Normal-Mode Rejection ...................................................................3-6
Effective CMR ..................................................................................3-6
Timing and Control Functional Overview ......................................................3-7
Programmable Function Inputs .......................................................................3-8
Device and PXI Clocks ...................................................................................3-9
Developing Your Application........................................................................................3-11
Typical Program Flow Chart...........................................................................3-11

Contents
NI PXI-4204 User Manual vi ni.com
General Discussion of Typical Flow Chart..................................................... 3-13
Creating a Task Using DAQ Assistant or Programmatically ........... 3-13
Adjusting Timing and Triggering..................................................... 3-14
Configuring Channel Properties ....................................................... 3-14
Acquiring, Analyzing, and Presenting.............................................. 3-15
Completing the Application.............................................................. 3-15
Developing an Application Using LabVIEW ................................................. 3-16
Using a DAQmx Channel Property Node in LabVIEW................... 3-17
Synchronization and Triggering...................................................................... 3-19
Synchronizing the NI PXI-4204 ..................................................................... 3-19
Synchronizing the NI PXI-4204 Using LabVIEW........................... 3-21
Other Application Documentation and Material ........................................................... 3-22
Calibrating the NI PXI-4204 ......................................................................................... 3-23
Loading Calibration Constants........................................................................ 3-23
Self-Calibration............................................................................................... 3-23
External Calibration ........................................................................................ 3-24
Appendix A
Specifications
Appendix B
Timing Signal Information
Appendix C
Removing the NI PXI-4204
Appendix D
Common Questions
Glossary
Index
Figures
Figure 2-1. Installing the NI PXI-4204 Device ....................................................... 2-2
Figure 2-2. NI PXI-4204 Screw Terminals ............................................................. 2-4
Figure 2-3. NI PXI-4204 Front Label...................................................................... 2-5
Figure 2-4. Floating Signal Source Connection ...................................................... 2-6
Figure 2-5. Shielded Floating Signal Source Connection (Recommended)............ 2-7

Contents
©National Instruments Corporation vii NI PXI-4204 User Manual
Figure 2-6. Ground-Referenced Signal Connection.................................................2-9
Figure 2-7. Recommended Shielded Ground-Referenced Signal Connection.........2-10
Figure 2-8. Alternative Shielded Ground Referenced Signal Connection ...............2-11
Figure 2-9. High CMV Connection .........................................................................2-12
Figure 2-10. Shielded High CMV Connection ..........................................................2-13
Figure 3-1. Block Diagram of NI PXI-4204 ............................................................3-2
Figure 3-2. Effect of Input Impedance on Signal Measurements ............................3-5
Figure 3-3. AI CONV CLK Signal Routing ............................................................3-8
Figure 3-4. NI PXI-4204 PXI Trigger Bus Signal Connection................................3-10
Figure 3-5. Typical Program Flowchart...................................................................3-12
Figure 3-6. LabVIEW Channel Property Node with Filtering Enabled
at 10 kHz and SS/H Enabled .................................................................3-18
Figure 3-7. General Synchronizing Flowchart.........................................................3-20
Figure A-1. NI PXI-4204 Dimensions......................................................................A-6
Figure B-1. Typical Posttriggered Sequence ............................................................B-2
Figure B-2. Typical Pretriggered Sequence..............................................................B-2
Figure B-3. AI START TRIG Input Signal Timing .................................................B-3
Figure B-4. AI START TRIG Output Signal Timing...............................................B-3
Figure B-5. AI REF TRIG Input Signal Timing.......................................................B-4
Figure B-6. AI REF TRIG Output Signal Timing....................................................B-5
Figure B-7. AI SAMP CLK Input Signal Timing ....................................................B-6
Figure B-8. AI SAMP CLK Output Signal Timing..................................................B-6
Figure B-9. AI CONV CLK Input Signal Timing ....................................................B-7
Figure B-10. AI CONV CLK Output Signal Timing .................................................B-8
Figure B-11. AI SAMPLE CLK TIMEBASE Signal Timing ....................................B-9
Figure B-12. AI HOLD COMPLETE Signal Timing.................................................B-10
Figure C-1. Injector/Ejector Handle Position Before Device Removal....................C-2
Tables
Table 3-1. Signal Conditioning Functional Blocks ...............................................3-3
Table 3-2. PXI Trigger Bus Timing Signals...........................................................3-10
Table 3-3. NI-DAQmx Properties .........................................................................3-14
Table 3-4. Programming a Task in LabVIEW .......................................................3-16
Table 3-5. Synchronizing the NI PXI-4204 Using LabVIEW................................3-21
Table A-1. Maximum Sampling Rates ....................................................................A-1

©National Instruments Corporation 1-1 NI PXI-4204 User Manual
1
About the NI PXI-4204
The NI PXI-4204 is part of the PXI-4200 series of data acquisition (DAQ)
devices with integrated signal conditioning. The PXI-4200 series reduces
measurement setup and configuration complexity by integrating signal
conditioning and DAQ on the same product.
The NI PXI-4204 is a full-featured measurement device with
programmable filter and gain settings per channel, ensuring maximum
accuracy over the entire ±100 V input range. The NI PXI-4204 features the
National Instruments (NI) programmable gain instrumentation amplifier
(PGIA), an instrumentation-class amplifier that guarantees fast settling
times at all gain settings.
The NI PXI-4204 is an eight-channel device for measuring voltages up to
±100 volts. The NI PXI-4204 has the following features:
• Eight differential analog input (AI) channels
• 16-bit resolution
• 200 kS/s aggregate sampling rate
• 22 kS/s per channel when simultaneously sampling all channels
• Input ranges of ±100, ±50, ±5, and ±0.5 V
• Two-pole software programmable Butterworth filters with software
selectable filter settings of 6 Hz and 10 kHz per channel
• Instrumentation amplifier per channel
• Track-and-hold (T/H) circuitry providing simultaneous
sample-and-hold (SS/H) capability
• Synchronization with other DAQ devices through the PXI trigger bus
• Direct connectivity through a removable COMBICON connector
You can configure most settings on a per-channel basis through software.
The NI PXI-4204 is configured using Measurement & Automation
Explorer (MAX) or through function calls to NI-DAQmx.

Chapter 1 About the NI PXI-4204
NI PXI-4204 User Manual 1-2 ni.com
What You Need to Get Started
To set up and use the NI PXI-4204, you need the following:
❑Hardware
– NI PXI-4204 device
– Safety shell (provided)
– COMBICON screw terminal connector (provided)
– PXI or PXI/SCXI combination chassis
❑Software
– NI-DAQ 7.0 or later
– One of the following:
•LabVIEW
• Measurement Studio
• LabWindows™/CVI™
❑Documentation
– NI PXI-4204 User Manual
–Read Me First: Safety and Radio-Frequency Interference
– DAQ Getting Started Guide
– PXI or PXI/SCXI combination chassis user manual
– Documentation for your software
❑Tools
– 1/8 in. flathead screwdriver
You can download NI documents from ni.com/manuals.
National Instruments Documentation
The NI PXI-4204 User Manual is one piece of the documentation set for
your DAQ system. You could have any of several types of manuals,
depending on the hardware and software in your system. Use the
documentation you have as follows:
•DAQ Getting Started Guide—This document describes how to install
DAQ devices and the NI-DAQ driver software. Install NI-DAQ before
you install the SCXI module.

Chapter 1 About the NI PXI-4204
©National Instruments Corporation 1-3 NI PXI-4204 User Manual
•SCXI Quick Start Guide—This document describes how to set up
an SCXI chassis, install SCXI modules and terminal blocks, and
configure the SCXI system in MAX.
• PXI or PXI/SCXI combination chassis manual—Read this manual
for maintenance information about the chassis and for installation
instructions.
• Accessory installation guides or manuals—If you are using accessory
products, read the terminal block installation guides. It explain how to
physically connect the relevant pieces of the system. Consult this guide
when you are making the connections.
• Software documentation—You may have both application software
and NI-DAQmx software documentation. NI application software
includes LabVIEW, Measurement Studio, and LabWindows/CVI.
After you set up the hardware system, use either your application
software documentation or the NI-DAQmx documentation to help you
write your application. If you have a large, complicated system, it is
worthwhile to look through the software documentation before you
configure the hardware.
Installing the Application Software, NI-DAQ, and the
DAQ Device
Refer to the DAQ Getting Started Guide, packaged with the NI-DAQ
software, to install your application software and NI-DAQ driver software.
NI-DAQ 7.0 or later is required to configure and program the NI PXI-4204
device. If you do not have NI-DAQ 7.0 or later, you can either contact an
NI sales representative to request it on a CD or download the latest NI-DAQ
version from ni.com.
Installing the NI PXI-4204
Note Refer to the Read Me First: Safety and Radio-Frequency Interference document
before removing equipment covers or connecting or disconnecting any signal wires.
Refer to the DAQ Getting Started Guide to unpack, install, and configure
the NI PXI-4204 in a PXI chassis and then to the SCXI Quick Start Guide
if you are using a PXI/SCXI combination chassis.

Chapter 1 About the NI PXI-4204
NI PXI-4204 User Manual 1-4 ni.com
LED Pattern Descriptions
The following LEDs on the NI PXI-4204 front panel confirm the system is
functioning properly:
• The ACCESS LED is normally green and blinks yellow for a minimum
of 100 ms during the NI PXI-4204 configuration.
• The ACTIVE LED is normally green and blinks yellow for a minimum
of 100 ms during data acquisition.

©National Instruments Corporation 2-1 NI PXI-4204 User Manual
2
Connecting Signals
This chapter provides information about the NI PXI-4204 front signal
connector and how to connect signals to the NI PXI-4204.
Connecting Signals to the NI PXI-4204
After you have verified that the NI PXI-4204 is installed correctly and
self-tested the device, refer to the following sections to connect signals to
the device.
Caution You must clamp the safety shell over the COMBICON connector to prevent
accidental contact with hazardous voltages. Refer to Figure 2-1 for information about how
to properly install the NI PXI-4204 and safety shell.

Chapter 2 Connecting Signals
NI PXI-4204 User Manual 2-2 ni.com
Figure 2-1. Installing the NI PXI-4204 Device
Caution Refer to the Read Me First: Safety and Radio-Frequency Interference document
before removing equipment covers or connecting/disconnecting any signal wires.
1 PXI Chassis
2 PXI System Controller
3 NI PXI-4204 Device
4 COMBICON Connector
5 Injector/Ejector Handle
6 Safety Shell
7 Guides
2
5
PXI-1000B
6
7
4
3
1

Chapter 2 Connecting Signals
©National Instruments Corporation 2-3 NI PXI-4204 User Manual
Front Signal Connector
The NI PXI-4204 is a direct-connect device. The connection interface
consists of a 16-pin COMBICON connector and one SMB connector.
Figure 2-2 shows the pin assignments for the signals. Figure 2-3 shows the
front label of the NI PXI-4204, with each set of screw terminals labeled
according to the corresponding differential input signal. To connect a
signal to the NI PXI-4204, complete the following steps while referring to
Figures 2-2 and 2-3:
1. Remove power from the signal lines. If this is not possible, complete
the following steps while referring to Figures 2-2, and 2-3.
a. Remove the COMBICON connector from the NI PXI-4204.
b. Attach the signal sources according to the instructions in steps 2
through 4.
c. Ensure the NI PXI-4204 is powered on.
d. Reinstall the COMBICON connector.
2. Strip 7 mm (0.25 in.) of insulation from the ends of the signal wires.
3. Insert the wires into the screw terminals.
4. Tighten the screws to 0.5–0.6 N · m (4.4–5.3 lb · in.) of torque.
Connect a timing or triggering signal to the PFI0/CAL SMB connector
using a cable with an SMB signal connector.
Caution The PFI0/CAL SMB connector is for low-voltage timing and calibration signals
only. Voltages greater than ±15 V can damage the device.

Chapter 2 Connecting Signals
NI PXI-4204 User Manual 2-4 ni.com
Figure 2-2. NI PXI-4204 Screw Terminals
AI5–
AI4+
AI3+
AI7+
AI6–
AI6+
AI4–
AI2–
AI2+
AI1–
AI1+
AI0–
AI0+
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
AI3–
AI5+
AI7–
PFI 0/
CAL

Chapter 2 Connecting Signals
©National Instruments Corporation 2-5 NI PXI-4204 User Manual
Figure 2-3. NI PXI-4204 Front Label
Analog Input Connections
The following sections provide a definition of the signal source
characteristics, descriptions of various ways to connect signals to the
NI PXI-4204, and electrical diagrams showing the signal source and
connections. Whenever possible, use shielded twisted-pair field wiring
to reduce the effects of unwanted noise sources.
In the electrical diagrams, two different ground symbols are used. These
symbols indicate that you cannot assume that the indicated grounds are at
the same potential. Refer to Appendix A, Specifications, for maximum
working voltage specifications.
NI PXI-4204
8 Channel 100 V Input
ACCESS ACTIVE
PFI 0/
CAL
100 V
CAT I
AI 0
+
–
AI 1
+
–
AI 2
+
–
AI 3
+
–
AI 4
+
–
AI 5
+
–
AI 6
+
–
AI 7
+
–

Chapter 2 Connecting Signals
NI PXI-4204 User Manual 2-6 ni.com
Floating Signal Source Connection
Figure 2-4 illustrates the floating signal source connection. In this
configuration, the signal source being measured is a floating signal source,
such as a battery.
To connect a floating signal source connection to the NI PXI-4204, the
signal (VSIG +) is connected to the NI PXI-4204 channel (AIX+). The signal
reference (VSIG–) is connected to the channel reference (AIX–). The lack of
shielding on the field wiring can cause this configuration to be susceptible
to electrically coupled noise.
This configuration has only one ground connection—at the instrument—so
there is no potential difference between grounds to introduce error in your
measurements. The NI PXI-4204 input attenuators provide a ground
reference for floating signal sources; therefore, external grounding bias
resistors are not required.
Figure 2-4. Floating Signal Source Connection
+
–
+
–
+
–
Twisted-Pair
Wiring AI0+
AI0–
AI7+
AI7–
CH0
CH7
VSIG
Chassis Ground
Reference
Signal Source

Chapter 2 Connecting Signals
©National Instruments Corporation 2-7 NI PXI-4204 User Manual
Shielded Floating Signal Source Connection
(Recommended)
The signal source shown in Figure 2-5 is identical to the one shown in
Figure 2-4. The only difference is the addition of shielding around the field
wiring.
You can improve the noise susceptibility of the floating signal source
connection, shown in Figure 2-4, by using a shielded cable to connect
the signal source to the instrument, as shown in Figure 2-5. This is the
recommended shielding configuration for floating signal sources. The
shielding is grounded at only one point to the NI PXI-4204 chassis ground
reference. Connect the signal (VSIG +) to the NI PXI-4204 channel (AIX+).
Connect the signal reference (VSIG –) to the channel reference (AIX–).
Figure 2-5. Shielded Floating Signal Source Connection (Recommended)
Shielding
+
–
+
–
+
–
Twisted-Pair
Wiring
AI0+
AI0–
AI7+
AI7–
CH0
CH7
VSIG
Chassis Ground
Reference
Signal Source

Chapter 2 Connecting Signals
NI PXI-4204 User Manual 2-8 ni.com
Ground-Referenced Signal Connection
Figure 2-6 illustrates the ground-referenced signal connection. In this
configuration, the voltage source being measured is referenced to its own
ground reference that is connected through some conductive path to the
instrument ground reference. For example, the path can be through a
common earth ground or through the power line ground.
Note This connection is a characteristic of the signal source and no additional wiring
should be added to connect the signal source ground reference to the NI PXI-4204 ground
reference.
To connect a ground-reference signal source to the NI PXI-4204, the signal
(VSIG +) is connected to the NI PXI-4204 channel (AIX+). The signal
reference (VSIG –) is connected to the channel reference (AIX–). The
signal ground reference (VSIG Ground Reference) is referenced to the
NI PXI-4204 chassis ground reference inherently through some conductive
path that you do not physically connect.
This configuration is very simple to connect, but it also can be susceptible
to capacitive or electrically coupled noise. Also, the difference in ground
potential between the signal source ground and instrument ground creates
an unwanted signal that can introduce an error into the measurement. This
error is presented as a common-mode voltage (CMV) to the differential
front end of the NI PXI-4204, and is reduced by the common-mode
rejection (CMR) of the differential instrumentation amplifier. The
effectiveness of the CMR is affected by the source resistance of the signal
being measured. For more information about the effect of source resistance
on CMR, refer to the Measurement Considerations section of Chapter 3,
Using the NI PXI-4204.

Chapter 2 Connecting Signals
©National Instruments Corporation 2-9 NI PXI-4204 User Manual
Figure 2-6. Ground-Referenced Signal Connection
Shielded Ground-Referenced Signal Connection
(Recommended)
Figure 2-7 illustrates a shielded ground-referenced signal connection. The
connection to this signal source is identical to the ground-referenced signal
connection with the addition of shielding around the field wiring.
The ground-referenced signal source in Figure 2-7 is identical to the signal
source in Figure 2-6.
The shielding is grounded at only one point to the signal source ground
(VSIG Ground Reference). Connect the signal (VSIG +) to the NI PXI-4204
channel (AIX+). Connect the signal reference (VSIG –) to the channel
reference (AIX–).
This shielding scheme is effective at reducing capacitive or electrically
coupled noise. The same concerns regarding the difference in ground
potentials, discussed in the Ground-Referenced Signal Connection section,
also apply to this configuration.
+
–
+
–
+
–
Twisted-Pair
Wiring AI0+
AI0–
AI7+
AI7–
CH0
CH7
VSIG
VSIG Ground
Reference
Chassis Ground
Reference
Signal Source