This document describes how to use the National Instruments 9233
and includes specifications and connector assignments for the
NI 9233. Visit ni.com/info and enter rdsoftwareversion to
determine which software you need for the modules you are using.
For information about installing, configuring, and programming
the system, refer to the system documentation. Visit
and enter
cseriesdoc for information about C Series
ni.com/info
documentation.
Note The safety guidelines and specifications in this
document are specific to the NI 9233. The other
components in the system might not meet the same safety
ratings and specifications. Refer to the documentation for
each component in the system to determine the safety
ratings and specifications for the entire system. Visit
ni.com/info and enter cseriesdoc for information
about C Series documentation.
NI 9233 Operating Instructions and Specifications 2ni.com
Safety Guidelines
Operate the NI 9233 only as described in these operating
instructions.
Hot Surface This icon denotes that the component may be
hot. Touching this component may result in bodily injury.
Safety Guidelines for Hazardous Locations
The NI 9233 is suitable for use in Class I, Division 2, Groups A, B,
C, D, T 4 ha zar dous locations; Class I, Zone 2, AEx nC IIC T4, and
Ex nC IIC T4 hazardous locations; and nonhazardous locations
only. Follow these guidelines if you are installing the NI 9233 in a
potentially explosive environment. Not following these guidelines
may result in serious injury or death.
Caution Do not disconnect I/O-side wires or connectors
unless power has been switched off or the area is known
to be nonhazardous.
Caution Do not remove modules unless power has been
switched off or the area is known to be nonhazardous.
Caution For Zone 2 applications, install the system
in an enclosure rated to at least IP 54 as defined by
IEC 60529 and EN 60529.
Caution For Zone 2 applications, connected signals must
be within the following limit:
Capacitance .......................... 0.2 μF max
Special Conditions for Hazardous Locations Use in Europe
This equipment has been evaluated as EEx nC IIC T4 equipment
under DEMKO Certificate No. 03 ATEX 0324020X. Each module
is marked II 3G and is suitable for use in Zone 2 hazardous
locations. If you are using the NI 9233 in Gas Group IIC hazardous
locations or in ambient temperatures of –40 °C ≤ Ta ≤ 70 °C, you
must use the device in an NI chassis that has been evaluated as
EEx nC IIC T4, Ex nA IIC T4, or Ex nL IIC T4 equipment.
NI 9233 Operating Instructions and Specifications 4ni.com
Special Conditions for Marine Applications
Some modules are Lloyd’s Register (LR) Type Approved for
marine applications. To verify Lloyd’s Register certification, visit
ni.com/certification and search for the LR certificate, or
look for the Lloyd’s Register mark on the module.
Caution To meet radio frequency emission requirements
for marine applications, use shielded cables and install
the system in a metal enclosure. Suppression ferrites
must be installed on power supply inputs near power
entries to modules and controllers. Power supply and
module cables must be separated on opposite sides of the
enclosure and must enter and exit through opposing
enclosure walls.
The NI 9233 has four BNC connectors that provide connections for
four simultaneously sampled analog input channels.
AI0+
AI0–
AI1+
AI1–
AI2+
AI2–
AI3+
AI3–
Figure 1. NI 9233 Connector Assignments
NI 9233 Operating Instructions and Specifications 6ni.com
Each channel has a BNC connector to which you can connect an
Integrated Electronic Piezoelectric (IEPE) sensor. The center pin
of the connector, AI+, provides the DC excitation and the AC
signal connection. The shell of the connector, AI–, provides the
excitation return path and the AC signal ground reference.
Yo u can connect ground-referenced or floating IEPE sensors to the
NI 9233. You can avoid picking up ground noise by using a floating
connection. Typical IEPE sensors have a case that is electrically
isolated from the IEPE electronics, so connecting the sensor to the
NI 9233 results in a floating connection even though the case of the
sensor is grounded. To further minimize ground noise, prevent
the metal shells of the BNC connectors from touching each other,
the modules, or the chassis.
If you make a ground-referenced connection between the IEPE
sensor and the NI 9233, make sure the voltage on the AI– shell
is in the common-mode range to ensure proper operation of the
NI 9233. The AI– shell is protected against accidental contact
with overvoltages within the overvoltage protection range. Refer
to the Specifications section for more information about operating
voltages and overvoltage protection. Figures 2 and 3 illustrate
connecting grounded and floating IEPE sensors to the NI 9233.
Figure 2. Connecting a Grounded IEPE Sensor to the NI 9233
IEPE Sensor
AI+
+
–
AI–
NI 9233
Figure 3. Connecting a Floating IEPE Sensor to the NI 9233
NI 9233 Operating Instructions and Specifications 8ni.com
The NI 9233 analog input channels are referenced to the chassis
ground through a 50 Ω resistor. To minimize ground noise, make
sure that the chassis ground is connected to the earth ground. Each
channel is protected from overvoltages. The NI 9233 provides
an IEPE excitation current for each input signal. The signal is
AC-coupled, buffered, and conditioned. The signal is then sampled
by a 24-bit Delta-Sigma ADC. The NI 9233 IEPE excitation
current and AC coupling are always enabled. Refer to Figure 4 for
an illustration of the input circuitry for one channel of the NI 9233.
Excitation
Current
AC
AI+
AI–
50 Ω
Figure 4. Input Circuitry for One Channel of the NI 9233
The NI 9233 also has TEDS circuitry. For more information about
TEDS, visit
ni.com/info and enter rdteds.
Understanding NI 9233 Filtering
The NI 9233 uses a combination of analog and digital filtering
to provide an accurate representation of in-band signals while
rejecting out-of-band signals. The filters discriminate between
signals based on the frequency range, or bandwidth, of the signal.
The three important bandwidths to consider are the passband, the
stopband, and the alias-free bandwidth.
The NI 9233 represents signals within the passband, as quantified
primarily by passband flatness and phase nonlinearity. All signals
that appear in the alias-free bandwidth are either unaliased signals
or signals that have been filtered by at least the amount of the
stopband rejection.
Passband
The signals within the passband have frequency-dependent gain or
attenuation. The small amount of variation in gain with respect to
frequency is called the passband flatness. The digital filters of the
NI 9233 adjust the frequency range of the passband to match the
data rate. Therefore, the amount of gain or attenuation at a given
NI 9233 Operating Instructions and Specifications 10ni.com
frequency depends on the data rate. Figure 5 shows typical
passband flatness for data rates above 25.65 kS/s and less than
or equal to 25.65 kS/s.
0.025
Data Rate
> 25.65 kS/s
0.000
Gain (dB)
–0.025
Data Rate
≤
25.65 kS/s
–0.050
0.30. 20.10
Frequency/Data Rate
0.50.4
Figure 5. Typical Passband Flatness for the NI 9233
The relative phases of these signals also have a
frequency-dependent delay. The variation in the phase delay with
frequency is called the phase nonlinearity. Figure 6 shows the
phase nonlinearity for data rates above 25.65 kS/s and less than or
equal to 25.65 kS/s. The phase nonlinearity scales directly with the
oversample rate, so the two curves normalize the signal frequency
to the data rate.
NI 9233 Operating Instructions and Specifications 12ni.com
The filter significantly attenuates all signals above the stopband
frequency. The primary goal of the filter is to prevent aliasing.
Therefore, the stopband frequency scales precisely with the data
rate. The stopband rejection is the minimum amount of attenuation
applied by the filter to all signals with frequencies within the
stopband.
Alias-Free Bandwidth
Any signal that appears in the alias-free bandwidth of the NI 9233
is not an aliased artifact of signals at a higher frequency. The
alias-free bandwidth is defined by the ability of the filter to reject
frequencies above the stopband frequency and it is equal to the data
rate minus the stopband frequency.
Understanding NI 9233 Data Rates
The frequency of a master timebase (fM) controls the data rate (fs)
of the NI 9233. The NI 9233 includes an internal master timebase
with a frequency of 12.8 MHz, but the module also can accept an
external master timebase or export its own master timebase. To
synchronize the data rate of an NI 9233 with other modules that use
master timebases to control sampling, all of the modules must
NI 9233 Operating Instructions and Specifications 14ni.com
share a single master timebase source. Refer to the software help
f
f
for information about configuring the master timebase source for
the NI 9233. Visit ni.com/info and enter cseriesdoc for
information about C Series documentation.
The following equations provide the available data rates of the
NI 9233:
256÷
M
When fs is ≤ 25.65 kS/s, fs =
---------------------
n
where n is any integer from 2 to 25.
128÷
M
When fs is > 25.65 kS/s, fs =
---------------------
n
where n is any integer from 2 to 3.
However, the data rate must remain within the appropriate data rate
range. Refer to the Specifications section for more information
about the data rate range. When using the internal master timebase
of 12.8 MHz, the result is data rates of 50 kS/s, 33.33 kS/s, 25 kS/s,
and so on down to 2.0 kS/s, depending on the value of n. When
using an external timebase with a frequency other than 12.8 MHz,
the NI 9233 has a different set of data rates.
Note The cRIO-9151 R Series Expansion chassis does
not support sharing timebases between modules.
Sleep Mode
This module supports a low-power sleep mode. Support for sleep
mode at the system level depends on the chassis that the module is
plugged into. Refer to the chassis manual for information about
support for sleep mode. If the chassis supports sleep mode, refer to
the software help for information about enabling sleep mode. Visit
ni.com/info and enter cseriesdoc for information about
C Series documentation.
Typically, when a system is in sleep mode, you cannot
communicate with the modules. In sleep mode, the system
consumes minimal power and may dissipate less heat than it does
in normal mode. Refer to the Specifications section for more
information about power consumption and thermal dissipation.
NI 9233 Operating Instructions and Specifications 16ni.com
Specifications
The following specifications are typical for the range –40 to 70 °C
unless otherwise noted.
Input Characteristics
Number of channels .......................... 4 analog input channels
Refer to the product Declaration of Conformity (DoC) for
additional regulatory compliance information. To obtain product
certifications and the DoC for this product, visit ni.com/
certification
, search by module number or product line,
and click the appropriate link in the Certification column.
Shock and Vibration
To meet these specifications, you must panel mount the system.
Operating vibration
Random (IEC 60068-2-64)......... 5 g
Sinusoidal (IEC 60068-2-6) .......5 g, 10 to 500 Hz
NI 9233 Operating Instructions and Specifications 28ni.com
, 10 to 500 Hz
rms
Operating shock
(IEC 60068-2-27).............................. 30 g, 11 ms half sine,
50 g, 3 ms half sine,
18 shocks at 6 orientations
Environmental
National Instruments C Series modules are intended for indoor use
only but may be used outdoors if installed in a suitable enclosure.
Refer to the manual for the chassis you are using for more
information about meeting these specifications.
Operating temperature
(IEC 60068-2-1, IEC 60068-2-2) .....–40 to 70 °C
Storage temperature
(IEC 60068-2-1, IEC 60068-2-2) .....–40 to 85 °C
Ingress protection.............................. IP 40
Operating humidity
(IEC 60068-2-56).............................. 10 to 90% RH,
noncondensing
Storage humidity
(IEC 60068-2-56).............................. 5 to 95% RH,
Maximum altitude............................. 2,000 m
Pollution Degree (IEC 60664).......... 2
Environmental Management
NI is committed to designing and manufacturing products in
an environmentally responsible manner. NI recognizes that
eliminating certain hazardous substances from our products is
beneficial to the environment and to NI customers.
For additional environmental information, refer to the NI and the Environment Web page at ni.com/environment. This page
contains the environmental regulations and directives with which
NI complies, as well as other environmental information not
included in this document.
Waste Electrical and Electronic Equipment (WEEE)
EU Customers At the end of the life cycle, all products
must be sent to a WEEE recycling center. For more
information about WEEE recycling centers and National
Instruments WEEE initiatives, visit
environment/weee
NI 9233 Operating Instructions and Specifications 30ni.com
.
ni.com/
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about China RoHS compliance, go to
environment/rohs_china
Calibration
Yo u can obtain the calibration certificate and information about
calibration services for the NI 9233 at
Calibration interval ........................... 1 year
The National Instruments Web site is your complete resource for
technical support. At
everything from troubleshooting and application development
self-help resources to email and phone assistance from
NI Application Engineers.
National Instruments corporate headquarters is located at
11500 North Mopac Expressway, Austin, Texas, 78759-3504.
National Instruments also has offices located around the world to
help address your support needs. For telephone support in the
United States, create your service request at
and follow the calling instructions or dial 512 795 8248. For
telephone support outside the United States, contact your local
branch office:
Australia 1800 300 800, Austria 43 662 457990-0,
Belgium 32 (0) 2 757 0020, Brazil 55 11 3262 3599,
Canada 800 433 3488, China 86 21 5050 9800,
Czech Republic 420 224 235 774, Denmark 45 45 76 26 00,
Finland 358 (0) 9 725 72511, France 01 57 66 24 24,
Germany 49 89 7413130, India 91 80 41190000,
Israel 972 3 6393737, Italy 39 02 41309277, Japan 0120-527196,
NI 9233 Operating Instructions and Specifications 32ni.com
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in your software, the