National Instruments 9235 User manual

GETTING STARTED GUIDE
NI 9235
8 AI, ±29.4 mV/V, 24 Bit, 10 kS/s/ch
Simultaneous, 120 Ω Quarter-Bridge Completion

This document explains how to connect to the NI 9235.
Note Before you begin, complete the software and
hardware installation procedures in your chassis
documentation.
Note The guidelines in this document are specific to
the NI 9235. The other components in the system might
not meet the same safety ratings. Refer to the
documentation for each component in the system to
determine the safety and EMC ratings for the entire
system.
Safety Guidelines
Operate the NI 9235 only as described in this document.
Caution Do not operate the NI 9235 in a manner not
specified in this document. Product misuse can result in
a hazard. You can compromise the safety protection
built into the product if the product is damaged in any
way. If the product is damaged, return it to NI for
repair.
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Safety Voltages
Connect only voltages that are within the following limits:
Between any two terminals ±30 V maximum
Isolation
Channel-to-channel None
Channel-to-earth ground
Continuous 60 VDC,
Measurement Catergory I
Withstand 1,000 Vrms, verified by a 5 s
dielectric withstand test
Measurement Category I is for measurements performed on
circuits not directly connected to the electrical distribution system
referred to as MAINS voltage. MAINS is a hazardous live
electrical supply system that powers equipment. This category is
for measurements of voltages from specially protected secondary
circuits. Such voltage measurements include signal levels, special
equipment, limited-energy parts of equipment, circuits powered
by regulated low-voltage sources, and electronics.
NI 9235 Getting Started Guide | © National Instruments | 3

Caution Do not connect the NI 9235 to signals or use
for measurements within Measurement Categories II,
III, or IV.
Safety Guidelines for Hazardous Locations
The NI 9235 is suitable for use in Class I, Division 2, Groups A,
B, C, D, T4 hazardous locations; Class I, Zone 2, AEx nA IIC T4
and Ex nA IIC T4 hazardous locations; and nonhazardous
locations only. Follow these guidelines if you are installing the
NI 9235 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 Substitution of components may impair
suitability for Class I, Division 2.
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Caution For Division 2 and Zone 2 applications,
install the system in an enclosure rated to at least IP54
as defined by IEC/EN 60079-15.
Caution For Division 2 and Zone 2 applications,
connected signals must be within the following limits.
Capacitance 0.2 µF maximum
Special Conditions for Hazardous Locations Use
in Europe and Internationally
The NI 9235 has been evaluated as Ex nA IIC T4 Gc equipment
under DEMKO Certificate No. 07 ATEX 0626664X and is
IECEx UL 14.0089X certified. Each NI 9235 is marked II 3G
and is suitable for use in Zone 2 hazardous locations, in ambient
temperatures of -40 °C ≤ Ta ≤ 70 °C. If you are using the NI 9235
in Gas Group IIC hazardous locations, you must use the device in
an NI chassis that has been evaluated as Ex nC IIC T4, Ex IIC
T4, Ex nA IIC T4, or Ex nL IIC T4 equipment.
Caution You must make sure that transient
disturbances do not exceed 140% of the rated voltage.
NI 9235 Getting Started Guide | © National Instruments | 5

Caution The system shall only be used in an area of
not more than Pollution Degree 2, as defined in
IEC 60664-1.
Caution The system shall be mounted in an
ATEX/IECEx-certified enclosure with a minimum
ingress protection rating of at least IP54 as defined in
IEC/EN 60079-15.
Caution The enclosure must have a door or cover
accessible only by the use of a tool.
Electromagnetic Compatibility Guidelines
This product was tested and complies with the regulatory
requirements and limits for electromagnetic compatibility (EMC)
stated in the product specifications. These requirements and
limits provide reasonable protection against harmful interference
when the product is operated in the intended operational
electromagnetic environment.
This product is intended for use in industrial locations. However,
harmful interference may occur in some installations, when the
product is connected to a peripheral device or test object, or if the
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product is used in residential or commercial areas. To minimize
interference with radio and television reception and prevent
unacceptable performance degradation, install and use this
product in strict accordance with the instructions in the product
documentation.
Furthermore, any changes or modifications to the product not
expressly approved by National Instruments could void your
authority to operate it under your local regulatory rules.
Special Conditions for Marine Applications
Some products are Lloyd’s Register (LR) Type Approved for
marine (shipboard) applications. To verify Lloyd’s Register
certification for a product, visit ni.com/certification and search
for the LR certificate, or look for the Lloyd’s Register mark on
the product.
Caution In order to meet the EMC requirements for
marine applications, install the product in a shielded
enclosure with shielded and/or filtered power and
input/output ports. In addition, take precautions when
designing, selecting, and installing measurement probes
and cables to ensure that the desired EMC performance
is attained.
NI 9235 Getting Started Guide | © National Instruments | 7

Preparing the Environment
Ensure that the environment in which you are using the NI 9235
meets the following specifications.
Operating temperature
(IEC 60068-2-1, IEC 60068-2-2)
-40 °C to 70 °C
Operating humidity
(IEC 60068-2-78)
10% RH to 90% RH,
noncondensing
Pollution Degree 2
Maximum altitude 5,000 m
Indoor use only.
Note Refer to the device datasheet on ni.com/manuals
for complete specifications.
Connecting the NI 9235
The NI 9235 provides connections for eight 120 Ω quarter-bridge
input channels.
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Figure 1. NI 9235 Pinout
1
2
3
4
5
6
7
8
9
10
11
12
EXC1
AI1
RC1
EXC3
AI3
RC3
EXC5
AI5
RC5
EXC7
AI7
RC7
EXC0
AI0
RC0
EXC2
AI2
RC2
EXC4
AI4
RC4
EXC6
AI6
RC6
13
14
15
16
17
18
19
20
21
22
23
24
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Table 1. Signal Descriptions
Signal Description
EXC Provides the excitation voltage stimulus
AI Measures the bridge voltage
RC Provides the quarter-bridge completion
Connecting a Quarter-Bridge Sensor
You can connect quarter-bridge sensors to the NI 9235.
Figure 2. Connecting a Quarter-Bridge to One Channel
EXC
AI
RC NI 9235
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