Manual - National Instruments

INSTALLATION GUIDE
SCXI -1313A Terminal Block
™
This guide describes how to install and use the SCXI-1313A terminal block
with an SCXI-1125 module.
The SCXI-1313A terminal block is shielded and has screw terminals that
provide input connections for the SCXI-1125. Each SCXI-1313A channel
has a precision 100:1 resistive voltage divider that you can use to measure
voltages of up to 150 Vrms or ±150 VDC. You can individually bypass these
voltage dividers for low-voltage measurement applications.
The terminal block has 18 screw terminals for easy signal connection.
One pair of screw terminals connects to the SCXI-1125 chassis ground.
The remaining eight pairs of screw terminals connect signals to the eight
analog inputs.
Conventions
The following conventions are used in this guide:
»
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.
monospace italic
Italic text in this font denotes text that is a placeholder for a word or value
that you must supply.
What You Need to Get Started
To set up and use the SCXI-1313A terminal block, you need the following
items:
❑ Hardware
–
SCXI-1313A terminal block
–
SCXI-1125 module
–
SCXI or PXI/SCXI combination chassis
–
Cabling and sensors as required for your application
❑ Tools
–
Number 1 and 2 Phillips-head screwdrivers
–
1/8 in. flathead screwdriver
–
Long-nose pliers
–
Wire cutter
–
Wire insulation stripper
❑ Documentation
–
SCXI-1313A Terminal Block Installation Guide
–
Read Me First: Safety and Radio-Frequency Interference
–
DAQ Getting Started Guide
–
SCXI Quick Start Guide
–
SCXI-1125 User Manual
–
SCXI chassis or PXI/SCXI combination chassis user manual
You can download needed documents from ni.com/manuals.
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Connecting Signals
Note Refer to the Read Me First: Safety and Radio-Frequency Interference document
before removing equipment covers or connecting or disconnecting any signal wires.
To connect the signal to the terminal block, refer to Figures 1 and 2 while
completing the following steps:
10
9
WA
RN
IN
G:
7
1
6
8
2
5
3
4
Back View
1
2
3
4
Front View
Top Cover Screws
Top Cover
Terminal Block Enclosure
Thumbscrew (2)
5
6
7
Rear Connector
Circuit Board
Safety-Ground Lug
8 Circuit Board Attachment Screws
9 Strain-Relief Bar
10 Strain-Relief Screws
Figure 1. SCXI-1313A Parts Locator Diagram
1.
Unscrew the top cover screws and remove the top cover.
2.
Loosen the strain-relief screws and remove the strain-relief bar.
3.
Prepare the signal wire by stripping the insulation no more than
7 mm (0.28 in.).
© National Instruments Corporation
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SCXI-1313A Terminal Block Installation Guide
4.
Run the signal wires through the strain-relief opening. If necessary,
add insulation or padding.
5.
Insert the stripped end of the signal wires fully into the terminal. Make
sure no exposed wire extends past the screw terminal. Exposed wire
increases the risk of a short circuit that can cause circuit failure.
1
2
3
9
8
1
2
3
4
5
6
7
5
Serial Number
Assembly Number and Revision Letter
Relays to Enable or Bypass the Attenuator (8 places)
Chassis Ground Terminal (2 places)
Product Name
4
6
7
8
9
Thermistor
Screw Terminal (16 places)
Channel Labeling (8 places)
Voltage Divider (8 places)
Figure 2. SCXI-1313A Circuit Board Parts Locator Diagram
6.
Tighten the terminal screws to a torque of 0.57 to 0.79 N ⋅ m
(5 to 7 lb - in.).
7.
Reinstall the strain-relief bar and tighten the strain-relief screws.
8.
Reinstall the top cover and tighten the top cover screws.
9.
Attach the SCXI-1313A to the SCXI-1125 using the thumbscrews.
10. Refer to the SCXI Quick Start Guide to power on the SCXI chassis and
configure the system in software.
For accurate cold-junction compensation, place the chassis away from an extreme
temperature differential.
Note
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Configuring the High-Voltage Attenuator
Each channel has a 100:1 high-voltage attenuator. To enable or disable
the attenuator, either change the default configuration settings for the
SCXI-1313A in Measurement & Automation Explorer (MAX) or adjust
the input limit ranges in your application. When using virtual channels, the
input limits configured in the virtual channel configurator are used to set
the attenuation circuitry appropriately.
SCXI-1313 is the designator for both the SCXI-1313 and SCXI-1313A in MAX
and NI-DAQ.
Note
The calibration EEPROM on the SCXI-1313A stores calibration constants
that provide software correction values. These values are used by the
application development software to correct the measurements for gain
errors in the attenuation circuitry.
Table 1. Input Signal Range Versus Gain
Overall
Gain
© National Instruments Corporation
Overall Voltage Range1
Module
Gain
Terminal
Block Gain
0.02
±150 Vrms or ±150 VDC
2
0.01
0.05
±100 Vpeak or ±100 VDC
5
0.01
0.1
±50 Vpeak or ±50 VDC
10
0.01
0.2
±25 Vpeak or ±25 VDC
20
0.01
0.5
±10 Vpeak or ±10 VDC
50
0.01
1
±5 Vpeak or ±5 VDC
1
1
2
±2.5 Vpeak or ±2.5 VDC
2
1
2.5
±2 Vpeak or ±2 VDC
250
0.01
5
±1 Vpeak or ±1 VDC
5
1
10
±500 mVpeak or ±500 mVDC
10
1
20
±250 mVpeak or ±250 mVDC
20
1
50
±100 mVpeak or ±100 mVDC
50
1
100
±50 mVpeak or ±50 mVDC
100
1
200
±25 mVpeak or ±25 mVDC
200
1
250
±20 mVpeak or ±20 mVDC
250
1
5
SCXI-1313A Terminal Block Installation Guide
Table 1. Input Signal Range Versus Gain (Continued)
Overall
Gain
1
Overall Voltage Range1
Module
Gain
Terminal
Block Gain
500
±10 mVpeak or ±10 mVDC
500
1
1000
±5 mVpeak or ±5 mVDC
1000
1
2000
±2.5 mVpeak or ±2.5 mVDC
2000
1
Refer to the Specifications section for the input range.
Calibrating the Terminal Block
Most external calibration documents for SCXI product are available to
download from ni.com/calibration by clicking Manual Calibration
Procedures. For external calibration of products not listed there, Basic
Calibration Service or Detailed Calibration Service is recommended.
You can get information about both of these calibration services at
ni.com/calibration. NI recommends performing an external
calibration once a year.
Temperature Sensor Output and Accuracy
The SCXI-1313A temperature sensor outputs 1.91 to 0.65 V from
0 to 50 °C.
Converting a Thermistor Voltage to a Temperature
NI software can convert a thermistor voltage to the thermistor temperature
for the circuit diagram shown in Figure 3. In LabVIEW, you can use the
Convert Thermistor Reading VI found in the Data Acquisition»Signal
Conditioning palette. If you are using CVI or NI-DAQmx, use the
Thermistor_Convert function. The VI takes the output voltage of the
temperature sensor, the reference voltage, and the precision resistance and
returns the thermistor temperature.
Alternatively, you can use the following formulas:
T(°C ) = T K – 273.15
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where TK is the temperature in Kelvin
1
T K = -------------------------------------------------------------3
[ a + b ( ln R T ) + c ( ln R T ) ]
a = 1.295361 × 10 –3
b = 2.343159 × 10 –4
c = 1.018703 × 10 –7
RT = resistance of the thermistor in ohms
V TEMPOUT ⎞
R T = 5,000 ⎛ ------------------------------------⎝ 2.5 – V TEMPOUT⎠
VTEMPOUT = output voltage of the temperature sensor
[ T ( °C ) ]9
T ( °F ) = ----------------------- + 32
5
where T(°F) and T(°C) are the temperature readings in degrees Fahrenheit
and degrees Celsius, respectively.
Note Use an average of a large number of samples to obtain the most accurate reading.
Noisy environments require more samples for greater accuracy.
Reading the Temperature Sensor in LabVIEW
In LabVIEW, to read VTEMPOUT, use NI-DAQmx with the following string:
SC(x)Mod(y)/_cjTemp
To read VTEMPOUT with Traditional NI-DAQ (Legacy), use the address
string:
obx ! scy ! mdz ! cjtemp
You can have this channel-address string in the same channel-string array
as other channels on the same SCXI-1125 module and call it multiple times
within the same channel-string array.
For more information about channel-string arrays and the SCXI
channel-addressing syntax, see the LabVIEW Measurements Manual.
© National Instruments Corporation
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SCXI-1313A Terminal Block Installation Guide
Temperature Sensor Circuit Diagram
You do not need to read this section to operate the SCXI-1313A.
The circuit diagram in Figure 3 is optional information that you can use
if you want more details about the SCXI-1313A temperature sensor.
+5 V
2.5 V
2
LM 4040
2.5 V
0.1%
0.1 µF
–t o
MTEMP
+ 1 10 µF
2 16 V
1
2
0.1 µF
Figure 3. Temperature Sensor Circuit Diagram
Specifications
All specifications are typical at 25 °C unless otherwise specified.
Input range ..............................................150 Vrms or VDC
Measurement category............................CAT II
Input channels.........................................8
Cold-junction sensor
Sensor type ......................................Thermistor
Accuracy1 ........................................±0.5 °C from 15 to 35 °C
±0.9 °C from 0 to 15 °C
and 35 to 55 °C
Repeatability....................................±0.2 °C from 15 to 35 °C
1
The temperature sensor accuracy includes tolerances in all component values, effects caused by temperature and loading, and
self-heating. Errors caused by temperature gradients between terminals and the sensor are not included in this specification.
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Output ............................................. 1.91 to 0.65 V
from 0 to 50 °C
Maximum temperature gradient
between sensor and any terminal .... ±0.4 °C (non-isothermal)
High-voltage divider
Accuracy ................................................ ±0.06% (for 100:1 setting)
Drift................................................. 15 ppm/°C
Resistance ....................................... 1 MΩ
Attenuation ratio ............................. 100:1 or 1:1
on programmatic basis
Common-mode isolation
Channel to channel.......................... 150 Vrms or ±150 VDC
Channel to ground........................... 150 Vrms or ±150 VDC
Coupling.......................................... DC only
Field-wiring connectors
Screw terminals
Signal terminals ....................... 16 (8 pairs)
Functional ground terminals .... 2
Maximum wire gauge .............. 16 AWG
Terminal spacing ..................... 0.5 cm (0.2 in.) center-to-center
Dimensions of front entrance.......... 1.2 × 7.3 cm
(0.47 × 2.87 in.)
Solder pads for
additional components .................... None
Safety earth-ground lugs ................. 1
Strain relief ..................................... Strain-relief bar at
terminal-block entrance
Maximum working voltage.................... 150 V
© National Instruments Corporation
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SCXI-1313A Terminal Block Installation Guide
Physical
30.3 mm
(1.19 in.)
82.5 mm
(3.25 in.)
NATIONAL
INSTRUMENTS
173.5 mm
(6.83 in.)
Figure 4. SCXI-1313A DImensions
Weight ....................................................408 g (14.4 oz)
Environment
Operating temperature ............................0 to 50 °C
Storage temperature ................................–20 to 70 °C
Humidity .................................................10 to 90% RH, noncondensing
Maximum altitude...................................2,000 meters
Pollution Degree (indoor use only) ........2
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Safety
This product 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, CSA 61010-1
Note 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.
Electromagnetic Compatibility
This product is designed to meet the requirements of the following
standards of EMC for electrical equipment for measurement, control,
and laboratory use:
Note
•
EN 61326 EMC requirements; Minimum Immunity
•
EN 55011 Emissions; Group 1, Class A
•
CE, C-Tick, ICES, and FCC Part 15 Emissions; Class A
For EMC compliance, operate this device according to product documentation.
CE Compliance
This product meets the essential requirements of applicable European
Directives, as amended for CE marking, as follows:
•
2006/95/EC; Low-Voltage Directive (safety)
•
2004/108/EC; Electromagnetic Compatibility Directive (EMC)
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.
Note
© National Instruments Corporation
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SCXI-1313A Terminal Block Installation Guide
Environmental Management
National Instruments is committed to designing and manufacturing
products in an environmentally responsible manner. NI recognizes that
eliminating certain hazardous substances from our products is beneficial
not only to the environment but also 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 any other environmental information not included in this document.
Waste Electrical and Electronic Equipment (WEEE)
At the end of their 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 ni.com/environment/weee.htm.
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