NI NISCXI-1521 24 quarter-bridge strain gage inputs/programmable excitation Datasheet

SCXI Quarter-Bridge Strain Gage Input Module
NEW
NI SCXI-1521, NI SCXI-1521B
inputs1
• 24 quarter-bridge strain gage
• 350 Ω (SCXI-1521)
• 120 Ω (SCXI-1521B)
• Programmable excitation
(0 to 5 V) per channel
• Programmable shunt and null
calibration per channel
• 10 Hz filter per channel
• Onboard quarter-bridge completion
and shunt calibration resistors
• NI-DAQmx 7.3 simplifies
configuration and measurements
Operating Systems
• Windows 2000/NT/XP
Recommended Software
• LabVIEW
• LabWindows/CVI
• Measurement Studio
Other Compatible Software
• Visual Basic, C, C++
Measurement Services
Software (included)
• NI-DAQmx 7.3
Calibration Certificate Included
1For half-bridge or full-bridge strain gage
measurements, please consider the SCXI-1520.
Overview
Null Compensation
The National Instruments SCXI-1521 and SCXI-1521B are quarterbridge strain gage input modules that offer all of the features you need
for high-channel-count applications. Each NI SCXI-1521/B is shipped
with a NIST-traceable calibration certificate.
Each SCXI-1521/B module can multiplex its signals into a single
channel of the controlling DAQ device, and you can add more
modules to increase channel count.
Each input channel of an SCXI-1521/B includes a circuit to remove
bridge offset voltage. Driver software nulls the offset voltage to zero
in seconds. You do not need to manually adjust a potentiometer. By
removing this offset through the measurement hardware, you can
achieve better measurement resolution.
Analog Input
Each of the 24 analog inputs of the SCXI-1521/B consists of a
quarter-bridge completion resistor (350 Ω for the SCXI-1521 and
120 Ω for the SCXI-1521B), and a 10 Hz, 2-pole Butterworth filter.
You can program the excitation over 1024 different levels from 0 to
5 V. The 2-pole Butterworth filters provides lowpass filtering to block
noise and ensure measurement accuracy.
Calibration
The SCXI-1521/B modules provide simple yet powerful calibration
capabilities. Each module has an onboard calibration EEPROM that
stores calibration constants for each channel; factory calibration
constants are stored in a protected area of the EEPROM.
NI-DAQ traditional and NI-DAQmx transparently use the
calibration constants to correct for gain and offset errors for
each channel.
Terminal Block
SCXI-1317
Type
Screw terminals
CJ Sensor
–
Table 1. Terminal Block Options for the SCXI-1521/B
Compatible Modules
SCXI-1521 & SCXI-1521B
Front-mounting
Shunt Calibration
Each input channel of an SCXI-1521/B includes an accurate and
stable shunt calibration resistor with which you can progamatically
simulate loading effects on your strain gage to compensate for
strain gage errors. The shunt calibration resistors located inside of
the module. You enable or disable the shunt resistors through
software commands.
Measurement Services Software
NI-DAQmx is the robust measurement services software included with all
National Instruments data acquisition and signal conditioning products.
This easy-to-use software tightly integrates the full functionality of your
DAQ hardware to LabVIEW, LabWindows/CVI, and Measurement Studio
for Visual Basic. High-performance features include multidevice
synchronization, networked measurements, and DMA data management.
Bundled with NI-DAQmx, the Measurement & Automation Explorer
(MAX) utility simplifies the configuration of your measurement hardware
with device test panels, interactive measurements, and scaled I/O channels.
NI-DAQmx also provides numerous example programs for LabVIEW
and other application development environments to get you started with
your application quickly.
Cabling
–
Special Functions
–
Part Number
777687-17
SCXI Quarter-Bridge Strain Gage Input Module
Ordering Information
NI SCXI-1521 ................................................................777966-21
NI SCXI-1521B ..........................................................777966-21B
Includes NI-DAQmx software.
For more information on extended warranty and value-added
services, visit ni.com/services
BUY ONLINE!
Visit ni.com/info
Specifications
This appendix lists the specifications for the SCXI-1521/B modules. These specifications are typical at
25 °C unless otherwise noted.
Analog Input
Number of channels.........................................
Voltage gain .....................................................
Input coupling...................................................
Overvoltage protection.....................................
Inputs protected ...............................................
24
42
DC
±11 V powered on and off
<AI0..23>
Transfer
Nonlinearity......................................................
Gain error
After calibration1 .......................................
Before calibration2.....................................
Input offset error ..............................................
0.02% max
SCXI-1521.........................................................
Long term stability ...........................................
SCXI-1521B.......................................................
Long term stability ...........................................
is the error after software correction. Gain error is taken into account in the software correction coefficients
stored in the onboard EEPROM. These constants are applied automatically when using LabVIEW or NI-DAQmx.
2This is the error before software calibration.
Dynamic
Minimum scan interval (per channel, any gain in multiplexed mode)
±0.012% accuracy ............................................ 3 µs
±0.006% accuracy ............................................ 10 µs
±0.0015% accuracy .......................................... 20 µs
Noise RTI1
0.1 to 10 Hz ...................................................... 2.5 µVpp
> 10 Hz.............................................................. 1 µVrms in 1MHz bandwidth
Shunt Calibration
Type .................................................................. Shunt across quarter-bridge completion resistor
Shunt resistor ................................................... Fixed 100 kΩ, 0.1%, 10 ppm/°C , 150mW
Switch resistance............................................. 15 Ω max
7.5 Ω typ
V+...................................................................... 18.5 to 25 VDC, +170 mA min
V........................................................................ 18.5 to –25 VDC, –170 mA min
+5 V .................................................................. +4.75 to 5.25 VDC, 50 mA min
Physical
Dimensions....................................................... 3.0 by 17.2 by 20.3 cm (1.2 by 6.9 by 8.0 in.)
Maximum Working Voltage
Maximum working voltage refers to the signal voltage plus the common-mode voltage.
Channel-to-earth .............................................. Input should remain within ±11 V of ground.
Installation Category I
Channel-to-channel .......................................... Input should remain within ±11 V of ground.
Installation Category I
Environmental
Filter
Operating temperature.....................................
Storage temperature ........................................
Humidity ...........................................................
Maximum altitude ............................................
Pollution Degree (indoor use only)...................
Lowpass filter type........................................... 2-pole Butterworth (12 dB/octave rolloff)
3 dB bandwidth ................................................ 10 Hz
Safety
1Includes
350 Ω, 0.1%, 2 ppm/°C max, 55mW @ °50 C
0.02%/yr
120 Ω, 0.1%, 2 ppm/°C max, 55mW @ °50 C
0.02%/yr
Power Requirements (from SCXI Backplane)
0.1% of reading max
4.0% of reading max
7 mV max
1 mV typ
1This
excitation voltage noise contribution
0 to 50 °C
20 to 70 °C
10 to 90% RH, noncondensing
2,000 m
2
Recommended warm-up time.......................... 30 minutes
Gain drift .......................................................... ±11 ppm /°C max
±4 ppm /°C typ
Offset drift ........................................................ ±3 µV /°C max
±1 µV /°C typ
The SCXI-1521/B is designed to meet the requirements of the following standards of safety for
electrical equipment for measurement, control, and laboratory use:
• IEC 61010-1, EN 61010-1
• UL 61010-1
• CAN/CSA-C22.2 No 61010-1
For UL and other safety certifications, refer to the product label, or visit ni.com/certification,
search by model number or product line, and click the appropriate link in the Certification column.
Offset Null Compensation
Electromagnetic Compatibility
Range................................................................ ±0.45% of excitation voltage
Resolutioin........................................................ 4,096 counts of resolution (±9,000 me offset null
compensation range, 4.4 me resolution for GF = 2.0)
EmissionsEN 55011 Class A at 10 m FCC Part 15A above 1 GHz
Immunity ..EN 61326:1997 + A2:2001, Table 1
EMC/EMICE, C-Tick, and FCC Part 15 (Class A) Compliant
Note: For EMC compliance, operate this device with shielded cabling.
Stability
Excitation
Type ..................................................................
Settings ............................................................
Error ..................................................................
Maximum output current .................................
Load regulation (open to 240 W) .....................
Temperature drift..............................................
Protection .........................................................
2
Bridge Completion
Constant voltage
0.0 to 5.0 V in 1023 steps
±20 mV ±0.3% max
21 mA
0.08%
±10ppm/°C ±30 µV/°C max
Surge arrestors in parallel with excitation terminals,
shunt to ground, short circuit protected
CE Compliance
The SCXI-1521/B meets the essential requirements of applicable European Directives,
as amended for CE marking, as follows:
Low-Voltage Directive (safety)......................... 73/23/EEC
Electromagnetic Compatibility
Directive (EMC) ................................................ 89/336/EEC
Note: Refer to the Declaration of Conformity (DoC) for this product for any additional regulatory
compliance information. To obtain the DoC for this product, visit ni.com/certification, search by
model number or product line, and click the appropriate link in the Certification column.
National Instruments • Tel: (800) 433-3488 • Fax: (512) 683-9300 • [email protected] • ni.com
NI Services and Support
NI has the services and support to meet your
needs around the globe and through the
application life cycle – from planning
and development through deployment
and ongoing maintenance. We offer
services and service levels to meet
customer requirements in research,
design, validation, and manufacturing.
Visit ni.com/services.
Local Sales and Technical Support
In offices worldwide, our staff is local to the country, giving you
access to engineers who speak your language. NI delivers industryleading technical support through online knowledge bases, our
applications engineers, and access to 14,000 measurement and
automation professionals within NI Developer Exchange forums.
Find immediate answers to your questions at ni.com/support.
We also offer service programs that provide automatic upgrades to
your application development environment and higher levels of
technical support. Visit ni.com/ssp.
Training and Certification
NI training is the fastest, most certain route to productivity with our
products. NI training can shorten your learning curve, save
development time, and reduce maintenance costs over the
application life cycle. We schedule instructor-led courses in cities
worldwide, or we can hold a course at your facility. We also offer a
professional certification program that identifies individuals who
have high levels of skill and knowledge on using NI products.
Visit ni.com/training.
Hardware Services
NI Factory Installation Services
NI Factory Installation Services (FIS) is the fastest and easiest way to
use your PXI or PXI/SCXI combination systems right out of the box.
Trained NI technicians install the software and hardware and
configure the system to your specifications. NI extends the standard
warranty by one year on hardware components (controllers, chassis,
modules) purchased with FIS. To use FIS, simply configure your
system online with ni.com/pxiadvisor.
Professional Services
Our Professional Services Team is comprised of NI applications
engineers, NI Consulting Services, and a worldwide NI Alliance
Partner Program of more than 600 independent consultants and
integrators. Services range
from start-up assistance to
turnkey system integration.
Visit ni.com/alliance.
Calibration Services
NI recognizes the need to maintain properly calibrated devices for
high-accuracy measurements. We provide manual calibration
procedures, services to recalibrate your products, and automated
calibration software specifically designed for use by metrology
laboratories. Visit ni.com/calibration.
Repair and Extended Warranty
OEM Support
We offer design-in consulting and product integration assistance
if you want to use our products for OEM applications. For
information about special pricing and services for OEM customers,
visit ni.com/oem.
NI provides complete repair services for our products. Express repair
and advance replacement services are also available. We offer
extended warranties to help you meet project life-cycle requirements.
Visit ni.com/services.
ni.com • (800) 433-3488
National Instruments • Tel: (512) 683-0100 • Fax: (512) 683-9300 • [email protected]
© 2004 National Instruments Corporation. All rights reserved. SCXI™, LabVIEW™, LabWindows/CVI™, Measurement Studio™, NI-DAQ™, and ni.com™ are trademarks of
National Instruments. Product and company names listed are trademarks or trade names of their respective companies.
Similar pages