National Instruments SCXI-1314T User manual

INSTALLATION GUIDE
SCXI -1314T TEDS Bridge Sensor
Terminal Block
This guide describes how to install and use the SCXI-1314T terminal block
with the SCXI-1520 module and hardware Transducer Electronic Data
Sheet (TEDS)-enabled bridge sensors (IEEE-P1451.4 Class 2).
The SCXI-1314T terminal block works with the SCXI-1520 universal
strain/bridge sensor module to conveniently connect hardware TEDS smart
sensors using RJ-50 10 position/10 conductor (10p10c) modular plugs.
There are 10 pins arranged in eight modular jacks. Each jack corresponds
to one of the eight channels available on the SCXI-1520. For a complete
description of the use and operation of the SCXI-1520 module, refer to the
SCXI-1520 User Manual.
Conventions
The following conventions are used in this manual:
»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.
When this icon is marked on the product, refer to the Read Me First: Safety
and Radio-Frequency Interference document, shipped with the product, for
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.
™

SCXI-1314T TEDS Bridge Sensor Terminal Block 2 ni.com
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. This font 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.
What You Need to Get Started
To install and use the SCXI-1314T terminal block, you need the
following items:
❑Hardware
– SCXI-1314T terminal block
– SCXI-1520 module
– SCXI or PXI/SCXI combination chassis
– Cabling, cable adapter, and Wheatstone-bridge sensors as
required for your application
❑Documentation
– Read Me First: Safety and Radio-Frequency Interference
– SCXI Quick Start Guide
– SCXI-1314T TEDS Bridge Sensor Terminal Block
Installation Guide
– SCXI-1520 User Manual
– SCXI or PXI/SCXI combination chassis user manual

©National Instruments Corporation 3 SCXI-1314T TEDS Bridge Sensor Terminal Block
❑Tools
– Number 2 Phillips screwdriver
– Long-nose pliers
– Wire cutter
– RJ-50 terminal crimper
❑Cables and plugs
– Shielded twisted pair (up to 5 pair, 10 conductor) cable
– Up to eight RJ-50 (10p10c) modular plugs
Note If your application does not require shunt calibration, you also can use RJ-45
10 position/8 conductor (10p8c) modular plugs in which only pins 2 through 9 are
populated. However, NI recommends using the RJ-50 (10p10c) for most applications.
Changing the Shunt Resistors
Note Refer to the Read Me First: Safety and Radio-Frequency Interference document
before removing equipment covers or connecting or disconnecting any signal wires.
Each channel input contains pins that connect to the inputs and outputs of
the SCXI-1520, and to a precision 100 kΩshunt calibration resistor. The
SCXI-1520 contains relays that switch the resistors in and out of the input
circuit to provide shunt calibration. These resistors are placed in sockets
on the SCXI-1314T terminal block so you can easily replace them with
resistors suitable to the specific Wheatstone-bridge sensor in your
application. If your application requires different shunt resistor values,
exchange the resistors with the appropriate value 1/4 W resistors.
Note Only the shunt resistors are socketed.

SCXI-1314T TEDS Bridge Sensor Terminal Block 4 ni.com
To change shunt resistors, complete the following steps, referring to
Figures 1 and 2 as necessary:
1. Unscrew the top cover screws and remove the top cover.
Figure 1. SCXI-1314T Parts Locator Diagram
2. Use long-nose pliers to carefully remove the socketed 100 kΩ
precision resistors.
Note To avoid damaging the precision resistors, pull the leads directly, alternating the
force back and forth rather than pulling the resistor itself.
3. Use wire cutters to shorten the new resistor leads to 6.4 mm (0.25 in.).
1 Top Cover Screws
2 Top Cover
3 RJ-50 Connector
4 Thumbscrew
1
2
3
4

©National Instruments Corporation 5 SCXI-1314T TEDS Bridge Sensor Terminal Block
4. Use long-nose pliers to insert the new resistors into the sockets,
indicated in Figure 2.
Figure 2. SCXI-1314T Shunt Resistor Sockets
5. Reinstall the top cover and tighten the top cover screws.
6. Refer to the SCXI Quick Start Guide to finish installing the
SCXI-1314T and configure it in Measurement & Automation Explorer
(MAX), and to find instructions for taking measurements.
1 Shunt Resistor Sockets
1

SCXI-1314T TEDS Bridge Sensor Terminal Block 6 ni.com
Channel Signals
Table 1 lists the signal names of the terminals for each channel, and lists
the correlation between the pin numbers of the RJ-50 (10p10c) modular
plug and the SCXI-1314T receptacle.
TEDS Sensor Bridge Configurations
This section describes the quarter-, half-, and full-bridge TEDS sensor
bridge configurations available for use with the SCXI-1314T.
Table 1. Channel Signal Names
RJ-50 (10p10c) Modular Plug
and SCXI-1314T Receptacle
Pin Numbers Pin Signal Name Signal Description
1SCA Shunt calibration
2AI + Positive input signal
3AI – Negative input signal
4RS + Positive remote sense signal
5RS – Negative remote sense signal
6EX + Positive excitation signal
7EX – Negative excitation signal
8T + TEDS data
9T – TEDS ground
10 SCA Shunt calibration
CH0
CH1
Pin 1
Pin 10
Pin 1
Pin 10

©National Instruments Corporation 7 SCXI-1314T TEDS Bridge Sensor Terminal Block
Quarter-Bridge
This section shows the quarter-bridge signal connections. Figure 3 shows
the quarter-bridge circuit wiring diagram.
Note AI – is left unwired. Set the SCXI-1520 module to internal half-bridge completion.
Refer to the SCXI-1520 User Manual for more information.
Figure 3. Quarter-Bridge Circuit Diagram
The following symbols apply to the circuit diagram and equations:
•R
1and R2are half-bridge completion resistors.
•R
3is the quarter-bridge completion resistor (dummy resistor) you
provide externally to the SCXI-1314T.
•R
4is the active measuring element.
+
–
+
–
AI +
EX +
EX –
R
L
R
L
R
L
SCA
SCA
Shunt
Cal A
SCXI-1520
Bridge Configuration
Set to Half BridgeSCXI-1314T
TEDS Transducer
V
AI
R1
R2
R
S
R4
(gauge)
V
EX
R3
(dummy)
R
L
R
L
+
–
V
RS
RS +
RS –
R
L
R
L
2
6
7
1
10
4
5
TEDS EEPROM T +
T –
8
9
Digital
Bus
TEDS
Comm
Circuitry
Digital
Communication
Circuitry

SCXI-1314T TEDS Bridge Sensor Terminal Block 8 ni.com
•VEX is the excitation voltage.
•RLis the lead resistance.
•VAI is the measured voltage.
•VRS is the remote sense measured excitation voltage.
•T+is the TEDS data transmission line.
•T–is the TEDS ground reference.
Note For greatest calibration accuracy, use separate wires between the bridge and the
SCA terminals as shown in Figure 3.

©National Instruments Corporation 9 SCXI-1314T TEDS Bridge Sensor Terminal Block
Half-Bridge
This section shows the half-bridge signal connections. Figure 4 shows the
half-bridge circuit wiring diagram.
Note AI – is left unwired. Set the SCXI-1520 module to internal half-bridge completion.
Refer to the SCXI-1520 User Manual for more information.
Figure 4. Half-Bridge Circuit Diagram
The following symbols apply to the circuit diagram and equations:
•R
1and R2are half-bridge completion resistors.
•R
3and R4are the active measuring elements.
•VEX is the excitation voltage.
+
–
+
–
AI +
EX +
EX –
R
L
R
L
R
L
SCA
SCA
Shunt
Cal A
SCXI-1520
Bridge Configuration
Set to Half BridgeSCXI-1314T
TEDS Transducer
V
AI
R1
R2
R
S
R4
(gauge)
V
EX
R3
(gauge)
R
L
R
L
+
–
V
RS
RS +
RS –
2
6
7
1
10
4
5
TEDS EEPROM T +
T –
8
9
Digital
Bus
TEDS
Comm
Circuitry
Digital
Communication
Circuitry
R
L
R
L

SCXI-1314T TEDS Bridge Sensor Terminal Block 10 ni.com
•RLis the lead resistance.
•VAI is the measured voltage.
•VRS is the remote sense measured excitation voltage.
•T+is the TEDS data transmission line.
•T–is the TEDS ground reference.
Note For greatest calibration accuracy, use separate wires between the bridge and the
SCA terminals as shown in Figure 4.