National Instruments SCXI -1314 Installation Manual

INSTALLATION GUIDE

™

SCXI -1314 U

NIVERSAL STRAIN TERMINALBLOCK

This guide describes how to install and use the SCXI-1314 terminal block with your SCXI-1520 module.

Introduction

The SCXI-1314 terminal block is used with the SCXI-1520 universal strain/bridge module enabling you to conveniently connect strain gauges through screw terminals. There are 88 screw terminals arranged in eight groups of 11. Each group corresponds to one of the eight channels available on the SCXI-1520. (Refer to Figure 2 for a diagram of terminal locations.) The signal names of the terminals for each channel are listed in Table 1.

Table 1.

Signal Name Condition

P+ Positive excitation signal

P– Negative excitation signal

S+ Positive input signal

S– Negative input signal

QTR Quarter-bridge completion resistor connection

RS+ Positive remote sense signal

RS– Negative remote sense signal

SCA

(2 terminals)

SCB

(2 terminals)

Each channel input contains screw terminals that connect to the inputs of the SCXI-1520, two precision 100 kΩ shunt calibration resistors, and a precision quarter-bridge completion resistor. The SCXI-1520 contains

Shunt calibration A signal

Shunt calibration B signal

Signal Names

National Instruments™, ni.com™, and SCXI™ are trademarks of National Instruments Corporation. Product and company names mentioned herein are trademarks or trade names of their respective companies.

322859A-01

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relays that switch the resistors in and out of the input circuit to provide shunt calibration and quarter-bridge completion.

The quarter-bridge completion resistor has a factory default value of 350 Ω for use with a 350 Ω strain gauge. These resistors are placed in sockets on the terminal block so you can easily replace them with resistors suitable to your specific strain gauge. If your application requires a 120 Ω strain gauge, use the eight 120 Ω resistors included in the kit.

For a complete description of the use and operation of the SCXI-1520 module, refer to the SCXI-1520 User Manual.

What You Need to Get Started

To install and use your SCXI-1314 terminal block, you need the following items:

SCXI-1314 terminal block

❑

SCXI-1314 Universal Strain Terminal Block Installation Guide

❑

Eight precision 120 Ω resistors for use in quarter-bridge completion

❑

circuits (if using 120 Ω strain gauges)

SCXI chassis

❑

SCXI-1520 module

❑

SCXI-1520 User Manual

❑

Number 1 and 2 Phillips-head screwdrivers

❑

1/8 in. flathead screwdriver

❑

Long-nose pliers

❑

Wire cutter

❑

Wire insulation stripper

❑

SCXI-1314 Universal Strain Terminal Block 2 ni.com

Connecting the Signals

To connect the signal to the terminal block, perform the following steps, referring to Figures 1 and 2 as necessary:

6

5

1 Top Cover Screws 2 Top Cover

7

4

3 Thumbscrew 4 Mating Connector

3

5 Strain-Relief Bar 6 Strain-Relief Screws

Figure 1.

SCXI-1314 Parts Locator Diagram

1

2

7 Safety-Ground

Lug

1. Unscrew the top cover screws and remove the top cover.

2. Loosen the strain-relief screws and remove the strain-relief bar.

3. Run the signal wires through the strain-relief opening. You can add insulation or padding if necessary.

4. Prepare your signal wire by stripping the insulation no more than 7 mm.

5. Connect the signal wires to the screw terminals by inserting the stripped end of the wire fully into the terminal. No bare wire should extend past the screw terminal. Exposed wire increases the risk of a short circuit that can cause circuit failure.

When connecting your signals to the SCXI-1314, follow the labeling on the SCXI-1314, as indicated in Figure 2.

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National Instruments Corporation 3 SCXI-1314 Universal Strain Terminal Block

R1

R3

R2

SCB

SCA

QTR

RPJ

J2 J3 J4 J5

CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7

SCB

SCA

P–

P+

SCA

QTR

S+

S–

RS+

RS–

QTR

UJ

SCB

SCA

P–

P+

SCA

QTR

S+

S–

RS+

RS–

QTR

UNIVERSAL STRAIN

SCB

SCA

P–

P+

QTR

S+

S–

RS+

RS–

SCXI-1314

J6 J7 J8 J9

SCB

SCA

QTR

RS+

RS–

SCBSCAQTR

SCA

P–

P+

QTR

S+

S–

RS+

RS–

J1

R4

SCB

SCBSCAQTR

SCA

QTR

RS+

RS–

P–

P+

QTR

S+

S–

RS+

RS–

1 2 3 4

5

C2

SCB

SCBSCAQTR

SCA

P–

P+

QTR

S+

S–

RS+

RS–

S/N

ASSY187212A-01

C3

Q1

SCBSCAQTR

R1

R3

R2

SCB

6

SCA

7

8

QTR

RPJ

J2 J3 J4 J5

SCB

SCA

P–

P+

SCA

QTR

S+

S–

RS+

RS–

QTR

CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7

UJ

SCB

SCA

P–

P+

SCA

QTR

S+

S–

RS+

RS–

QTR

1 Safety Ground Lug 2 Cable Strain Relief 3 Serial Number 4 Assembly Number 5 Screw Terminal and Associated Resistors

for <CH0...CH7>

6. Tighten the terminal screws to a torque of 5 to 7 in.-lb.

7. Reinstall the strain-relief bar and tighten the strain-relief screws.

8. Reinstall the top cover and tighten the top cover screws.

9. Connect the terminal block to the module front connector as explained in the Installing the Terminal Block section.

SCB

SCA

P–

P+

SCA

QTR

S+

S–

RS+

RS–

QTR

SCXI-1314

UNIVERSAL STRAIN

6 Shunt Calibration B Resistors, 8 places

7 Shunt Calibration A Resistors, 8 places

8 Quarter-Bridge Completion Resistor, 8 places

Figure 2.

J1

J6 J7 J8 J9

SCB

SCA

P–

P+

QTR

S+

S–

RS+

RS–

SCB

SCBSCAQTR

SCA

QTR

RS+

RS–

P–

P+

QTR

S+

S–

RS+

RS–

(Factory Default = 100 k

(Factory Default = 350

R4

SCB

SCBSCAQTR

SCA

P–

P+

QTR

S+

S–

RS+

RS–

Ω

,

SCXI-1314 Signal Connections

C2

SCB

SCBSCAQTR

SCA

P–

P+

QTR

S+

S–

RS+

RS–

S/N

ASSY187212A-01

,

0.1%)

,

0.1%)

C3

Q1

SCBSCAQTR

SCXI-1314 Universal Strain Terminal Block 4 ni.com

Installing the Terminal Block

To connect the terminal block to the SCXI module front connector, perform the following steps:

1. Connect the module front connector to its mating connector on the terminal block.

2. Tighten the top and bottom thumbscrews on the back of the terminal block to hold it securely in place.

Cleaning the Terminal Block

Clean the terminal block by brushing off light dust with a soft, nonmetallic brush. Remove other contaminants with deionized water and a stiff nonmetallic brush. The unit must be completely dry and free from contaminants before returning it to service.

Calibrating the Terminal Block

For information on calibrating the SCXI-1314 see the SCXI-1314 Universal Strain Terminal Block Calibration Procedure located online at

ni.com/calibration

Procedures.

and follow the link for Manual Calibration

Specifications

All specifications are typical at 25 °C unless otherwise specified.

Electrical

Accuracy of resistors

120 Ω completion resistor............... ±0.1%

350 Ω completion resistor............... ±0.1%

100 kΩ shunt calibration resistor.... ±0.1%

Temperature coefficient of resistors

120 Ω completion resistor............... ±10 ppm/°C

350 Ω completion resistor............... ±10 ppm/°C

100 kΩ shunt calibration resistor.... ±10 ppm/°C

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National Instruments Corporation 5 SCXI-1314 Universal Strain Terminal Block

Mechanical

Environment

Resistor sockets

Mating lead size...............................0.023 to 0.026 in.

Mating lead length...........................0.110 to 0.175 in.

Lead spacing....................................0.500 in.

Operating temperature ............................0 to 50 °C

Storage temperature................................–20 to 70 °C

Relative humidity ...................................10 to 90%

Indoor use only

SCXI-1314 Universal Strain Terminal Block 6 ni.com

National Instruments SCXI -1314 Installation Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Introduction

What You Need to Get Started

Connecting the Signals

Installing the Terminal Block

Cleaning the Terminal Block

Calibrating the Terminal Block

Specifications

Electrical

Mechanical

Environment