For user manuals and dimensional drawings, visit the product page resources tab on ni.com.
Last Revised: 2012-11-19 13:51:29.0
NI 9214
High-Accuracy Thermocouple Module
Multiple CJC sensors (cold-junction compensation)
Isothermal terminal block (included) for measurement accuracy up to 0.45 °C
250 Vrms channel-to-earth ground safety isolation
24-bit ADC for up to 0.02 °C measurement sensitivity
Autozero channel for offset error compensation
J, K, T, E, N, B, R, and S types supported
Overview
The NI 9214 is a high-density thermocouple module for NI C Series carriers designed for higher-channel-count systems that also need higher accuracy than the NI 9213 offers.
The NI 9214 has several features that increase overall accuracy including the following:
Front-mounting metal terminal block (TB-9214)
Multiple CJCs located in the terminal block
Component layout to minimize thermal gradients
You can use up to eight NI 9214 modules in an NI CompactDAQ chassis or CompactRIO chassis for 128 thermocouple measurements in a single chassis.
Each shipping kit contains the following:
NI 9214 module with spring-terminal connectivity
TB-9214 front-mounting terminal block
Printed manual
Note that the NI 9214 isothermal thermocouple module does not work with the legacy NI cDAQ-9172 chassis or any of the legacy 1-slot C Series carriers.
Back to Top
Requirements and Compatibility
OS Information
Real-Time OS
Windows
Driver Information
NI-DAQmx
NI-RIO
Software Compatibility
LabVIEW
LabWindows/CVI
Measurement Studio
SignalExpress
Visual Basic
Visual C#
Visual C++
Visual Studio
Visual Studio .NET
1/11
www.ni.com
Back to Top
Comparison Tables
Thermocouple Module
NI 9214
NI 9213
NI 9219
NI 9211
16
16
4
4
Channels
Sample Rate
1,088 S/s
1,200 S/s
50 S/s/ch
14 S/s
Resolution
24-bit
24-bit
24-bit
24-bit
High accuracy
Feature
Lowest cost per channel
Channel-to-channel isolation
Low channel count
Back to Top
Application and Technology
Channel Density for High-Channel-Count Systems
Temperature measurements can vary greatly over the different components in a machine, the surface of a device, or the volume of a given space. By taking more temperature
measurements, you can better quantify the thermal gradients and achieve more accurate test results. The NI 9214 was designed with density in mind to offer a large number of
thermocouple channels in a compact space. With up to eight NI 9214 modules installed in an NI CompactRIO or NI CompactDAQ chassis, you can measure up to 128
thermocouples in a system that fits inside a 9 by 9 by 26 cm box. For even more portable temperature measurement systems, you can install the NI 9214 into one of the single
module carriers for NI C Series modules to make 16-channel thermocouple measurements over USB, Ethernet, or Wi-Fi (802.11b/g).
CJC and Autozero for a More Accurate Measurement
The NI 9214 has built-in cold-junction compensation (CJC) to eliminate error caused by the physical connection of the sensor to the instrumentation. The contact of two dissimilar
metals creating a voltage potential is the principle on which thermocouples are designed, and, as such, the contact of the dissimilar thermocouple metal with the screw terminal
must be removed from the calculation. This is done through a process known as cold-junction compensation, with the cold junction being the mating of the sensor to the
instrument. All NI instrumentation designed for thermocouple measurement contains CJC circuitry including the NI 9211, NI 9219, NI 9213, and NI 9214. In addition to CJC, the NI
9214 features an extra, internal-only channel known as the autozero channel. By measuring the autozero channel at the beginning of each channel scan, you can eliminate further
offset errors to provide a more accurate temperature measurement.
Isothermal Terminal Block Design for Increased Accuracy
The TB-9214, which is shipped with the NI 9214 module, was designed to increase the accuracy of the thermocouple measurement. There are three main features that
significantly increase the accuracy of the NI 9214 over other thermocouple products.
1. Metal construction
By designing the terminal block with heavier metal, the measurement system is less likely to have hot spots when being used. Metal conducts heat better than plastic, which
makes it the better choice for temperature measurements. The goal is to have the instrumentation at a steady, uniform temperature that can be accounted for by the CJC sensors.
2. Multiple CJC sensors
The NI 9214 module features CJC sensors designed into the terminal block, which places them closer to the screw terminals. This minimizes any thermal gradient that may exist
between the connection and the sensor. In addition to proximity, multiple CJC sensors are used across the terminal block to better characterize the thermal gradient that may exist
in the TB-9214.
3. Component placement
The components of the NI 9214 circuit design were laid out to minimize thermal gradients between the CJC and the actual connections. This is an important aspect of the overall
accuracy because some components, by nature, heat up more than others during use.
C Series Compatibility
The NI C Series hardware family features more than 50 measurement modules and several chassis and carriers for deployment. With this variety of modules, you can mix and
match measurements such as temperature, acceleration, flow, pressure, strain, acoustic, voltage, current, digital, and more to create a custom system. Install the modules in one
of several carriers to create a single module USB, Ethernet, or Wi-Fi system, or combine them in chassis such as NI CompactDAQ and CompactRIO to create a
mixed-measurement system with synchronized measurements. You can install up to eight modules in a simple, complete NI CompactDAQ USB data acquisition system to
synchronize all of the analog output, analog input, and digital I/O from the modules. For a system without a PC, CompactRIO holds up to eight modules and features a built-in
processor, RAM, and storage for an embedded data logger or control unit. For higher-speed control, CompactRIO chassis incorporate a field-programmable gate array (FPGA)
that you can program with LabVIEW software to achieve silicon-speed processing on I/O data from C Series modules.
Back to Top
Software Recommendations
LabVIEW Professional Development System for Windows
Advanced software tools for large project development
Automatic code generation using DAQ Assistant and Instrument I/O Assistant
Tight integration with a wide range of hardware
Advanced measurement analysis and digital signal processing
Open connectivity with DLLs, ActiveX, and .NET objects
Capability to build DLLs, executables, and MSI installers
2/11
www.ni.com
Back to Top
Support and Services
System Assurance Programs
NI system assurance programs are designed to make it even easier for you to own an NI system. These programs include configuration and deployment services for your NI PXI,
CompactRIO, or Compact FieldPoint system. The NI Basic System Assurance Program provides a simple integration test and ensures that your system is delivered completely
assembled in one box. When you configure your system with the NI Standard System Assurance Program, you can select from available NI system driver sets and application
development environments to create customized, reorderable software configurations. Your system arrives fully assembled and tested in one box with your software preinstalled.
When you order your system with the standard program, you also receive system-specific documentation including a bill of materials, an integration test report, a recommended
maintenance plan, and frequently asked question documents. Finally, the standard program reduces the total cost of owning an NI system by providing three years of warranty
coverage and calibration service. Use the online product advisors at ni.com/advisor to find a system assurance program to meet your needs.
Calibration
NI measurement hardware is calibrated to ensure measurement accuracy and verify that the device meets its published specifications. To ensure the ongoing accuracy of your
measurement hardware, NI offers basic or detailed recalibration service that provides ongoing ISO 9001 audit compliance and confidence in your measurements. To learn more
about NI calibration services or to locate a qualified service center near you, contact your local sales office or visit ni.com/calibration.
Technical Support
Get answers to your technical questions using the following National Instruments resources.
Support
- Visit ni.com/support to access the NI KnowledgeBase, example programs, and tutorials or to contact our applications engineers who are located in NI sales
offices around the world and speak the local language.
Discussion Forums
- Visit forums.ni.com for a diverse set of discussion boards on topics you care about.
Online Community
- Visit community.ni.com to find, contribute, or collaborate on customer-contributed technical content with users like you.
Repair
While you may never need your hardware repaired, NI understands that unexpected events may lead to necessary repairs. NI offers repair services performed by highly trained
technicians who quickly return your device with the guarantee that it will perform to factory specifications. For more information, visit ni.com/repair.
Training and Certifications
The NI training and certification program delivers the fastest, most certain route to increased proficiency and productivity using NI software and hardware. Training builds the skills
to more efficiently develop robust, maintainable applications, while certification validates your knowledge and ability.
Classroom training in cities worldwide
- the most comprehensive hands-on training taught by engineers.
On-site training at your facility
- an excellent option to train multiple employees at the same time.
Online instructor-led training
- lower-cost, remote training if classroom or on-site courses are not possible.
Course kits
- lowest-cost, self-paced training that you can use as reference guides.
Training memberships
and training credits - to buy now and schedule training later.
Visit ni.com/training for more information.
Extended Warranty
NI offers options for extending the standard product warranty to meet the life-cycle requirements of your project. In addition, because NI understands that your requirements may
change, the extended warranty is flexible in length and easily renewed. For more information, visit ni.com/warranty.
OEM
NI offers design-in consulting and product integration assistance if you need NI products for OEM applications. For information about special pricing and services for OEM
customers, visit ni.com/oem.
Alliance
Our Professional Services Team is comprised of NI applications engineers, NI Consulting Services, and a worldwide National Instruments Alliance Partner program of more than
700 independent consultants and integrators. Services range from start-up assistance to turnkey system integration. Visit ni.com/alliance.
Back to Top
Detailed Specifications
3/11
www.ni.com
The following specifications are typical for the range –40 to 70 °C unless otherwise noted. The specifications are for the NI 9214 used in conjunction with an NI TB-9214.
Works over temperature ranges defined by NIST (J, K, T, E, N, B, R, S
thermocouple types)
Timing modes
Timing Mode
High-resolution
High-speed
*
Conversion Time (Per Channel)
52 ms
735 μs
0.96 S/s
68 S/s
Sample Rate
*
(All Channels
†
)
If you are using fewer than all channels, the sample rate might be faster. The maximum sample rate = 1/(
Conversion Time
×
Number of Channels
), or 100 S/s, whichever is
smaller. Sampling faster than the maximum sample rate may result in the degradation of accuracy.
†
Including the autozero and cold-junction channels.
Common-mode voltage range
Channel-to-COM
COM-to-earth ground
Common-mode rejection ratio
High-resolution mode (at DC and 50–60 Hz)
Channel-to-COM
COM-to-earth ground
High-speed mode (at 0–60 Hz)
Channel-to-COM
COM-to-earth ground
Thermocouple signal input bandwidth
High-resolution mode
High-speed mode
Open thermocouple settling time when switching OTD on/off
High-resolution noise rejection (at 50 and 60 Hz)
Overvoltage protection
Differential input impedance
Input noise
High-resolution mode
RMS
Crest factor
High-speed mode
220 nV
rms
6
14.4 Hz
80 Hz
6s
65 dB
±30 V between any two inputs
20 MΩ
70 dB
120 dB
100 dB
170 dB
±1.2 V min
±250 V
4/11
www.ni.com
RMS
Crest factor
Gain error
High-resolution mode
2.8 μV
rms
10
0.03% typ at 25 °C,
0.15% max at –40 to 70 °C
0.04% typ at 25 °C,
0.16% max at –40 to 70 °C
High-speed mode
Offset error
High-resolution mode
High-speed mode
Offset error from source impedance with OTD enabled
Input current
OTD enabled
OTD disabled
OTD bias current drift
Cold-junction compensation accuracy
23 ± 5 °C
–20 to 70 °C
–40 to 70 °C
MTBF
0.25 °C typ
0.6 °C max
0.9 °C max
Contact NI for Bellcore MTBF or MIL-HDBK-217F specifications.
200 nA
400 pA
200 pA/°C max
2 μV typ, 8 μV max
15 μV typ, 23 μV max
Add 0.2 μV per Ω
Temperature Measurement Accuracy
Measurement sensitivity
2
High-resolution mode
Types J, K, T, E, N
Types R, S
Type B
High-speed mode
Types J, K, T, E
Type N
Types R, S
Type B
0.10 °C
0.11 °C
0.36 °C
0.48 °C
0.01 °C
0.03 °C
0.04 °C
The following thermocouple measurement tables and graphs show the module accuracy for each thermocouple type under the following conditions:
Autozero is enabled.
Open thermocouple detection is disabled.
0 V common-mode voltage.
The tables include all measurement errors of the module and terminal block including RMS noise. The tables do not include the accuracy of the thermocouple itself.
Thermocouple Type J/N Measurement Accuracy (°C)
–100 °C 0 °C 100 °C 300 °C 500 °C 700 °C 900 °C 1100 °C
京公网安备 11010802033920号
EEWORLD
