NATIONAL INSTRUMENTS SCXI-1313A Terminal Block Installation Guide

: June 10, 2024
: NATIONAL INSTRUMENTS

Table of Contents

NATIONAL INSTRUMENTS SCXI-1313A Terminal Block
Product Information
Product Usage Instructions
Conventions
What You Need to Get Started
Connecting Signals
Configuring the High-Voltage Attenuator
Specifications
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

NATIONAL INSTRUMENTS SCXI-1313A Terminal Block

NATIONAL-INSTRUMENTS-SCXI-1313A-Terminal-Block-product

Product Information

The SCXI-1313A Terminal Block is a signal connection accessory that is intended to be used with an SCXI-1125 module. It includes 18 screw terminals for easy signal connection. One pair of screw terminals connects to the SCXI-1125 chassis ground while the remaining eight pairs of screw terminals connect signals to the eight analog inputs. The terminal block enclosure includes a safety-ground lug and a strain-relief bar that helps to secure the signal wires. The product is manufactured by National Instruments and is compatible with various hardware and software tools.

Product Usage Instructions

Before using the SCXI-1313A Terminal Block, ensure that you have the following items:

Hardware (SCXI-1313A Terminal Block, SCXI-1125 module, etc.)
Tools (screwdriver, wire stripper, etc.)
Documentation (SCXI-1313A Terminal Block Installation Guide)

To connect the signal to the terminal block, follow these steps:

Refer to the Read Me First: Safety and Radio-Frequency Interference document before removing equipment covers or connecting or disconnecting any signal wires.
Unscrew the top cover screws and remove the top cover.
Loosen the strain-relief screws and remove the strain-relief bar.
Prepare the signal wire by stripping the insulation no more than 7 mm (0.28 in.).
Run the signal wires through the strain-relief opening. If necessary, add insulation or padding.
Connect the signal wires to the appropriate screw terminals on the terminal block, referring to Figures 1 and 2 in the installation guide for assistance.
Secure the signal wires using the strain-relief bar and screws.
Replace the top cover and tighten the top cover screws.

Note that caution should be exercised when handling or connecting any signal wires, and that appropriate safety precautions should be taken in accordance with the Read Me First: Safety and Radio-Frequency Interference document.

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

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:

NATIONAL-INSTRUMENTS-SCXI-1313A-Terminal-Block-fig-1

Top Cover Screws
Top Cover
Terminal Block Enclosure
Thumbscrew (2)
Rear Connector
Circuit Board
Safety-Ground Lug
Circuit Board Attachment Screws
Strain-Relief Bar
Strain-Relief Screws

SCXI-1313A Parts Locator Diagram

Unscrew the top cover screws and remove the top cover.
Loosen the strain-relief screws and remove the strain-relief bar.
Prepare the signal wire by stripping the insulation no more than 7 mm (0.28 in.).
Run the signal wires through the strain-relief opening. If necessary, add insulation or padding.
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
Serial Number
Assembly Number and Revision Letter
Relays to Enable or Bypass the Attenuator (8 places)
Chassis Ground Terminal (2 places)
Product Name
Thermistor
Screw Terminal (16 places)
Channel Labeling (8 places)
Voltage Divider (8 places)
Tighten the terminal screws to a torque of 0.57 to 0.79 N ⋅ m (5 to 7 lb – in.).
Reinstall the strain-relief bar and tighten the strain-relief screws.
Reinstall the top cover and tighten the top cover screws.
Attach the SCXI-1313A to the SCXI-1125 using the thumbscrews.
Refer to the SCXI Quick Start Guide to power on the SCXI chassis and configure the system in software.

Note For accurate cold-junction compensation, place the chassis away from an extreme temperature differential

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. Note SCXI-1313 is the designator for both the SCXI-1313 and SCXI-1313A in MAX and NI-DAQ. 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.

Overall Gain|

Overall Voltage Range 1

| 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
Overall Gain|

Overall Voltage Range 1

| 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
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) = TK – 273.15

where TK is the temperature in Kelvin

a = 1.295361 × 10–3
b = 2.343159 × 10–4
c = 1.018703 × 10–7

RT = resistance of the thermistor in ohms

VTEMPOUT = output voltage of the temperature sensor

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

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

NATIONAL-INSTRUMENTS-SCXI-1313A-Terminal-Block-fig-5

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
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

Physical

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

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:

EN 61326 EMC requirements; Minimum Immunity
EN 55011 Emissions; Group 1, Class A
CE, C-Tick, ICES, and FCC Part 15 Emissions; Class A

Note 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)

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.

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)
EU Customers 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.

National Instruments, NI, ni.com, and LabVIEW are trademarks of National Instruments Corporation. Refer to the Terms of Use section on ni.com/legal for more information about National Instruments trademarks. Other product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your media, or ni.com/patents. © 2007–2008 National Instruments Corporation. All rights reserved