NI SCXI-1520

Description

1. Detailed Parameter Table

NI SCXI-1520

2. Product Introduction

The NI SCXI – 1520 is a high – performance 8 – channel universal strain / bridge input module engineered for use within SCXI (Signal Conditioning eXtensions for Instrumentation) systems. It serves as a critical component for accurately measuring and conditioning signals from strain gauges, load cells, force transducers, torque sensors, and pressure sensors, making it an ideal choice for applications that demand precise measurements in industrial, research, and test & measurement scenarios.

This module offers remarkable flexibility with its ability to configure channels in either differential (8 channels) or single – ended (16 channels) modes, catering to a wide variety of sensor types. Its 16 – bit resolution enables the detection of minute signal variations, while the selectable input ranges, spanning from ±1 mV to ±10 V, ensure compatibility with both low – level and higher – voltage sensor outputs. In data acquisition setups, the NI SCXI – 1520 acts as an interface between field sensors and data acquisition (DAQ) modules, enhancing the integrity of the measurement process by providing signal conditioning, isolation, and amplification.

3. Core Advantages and Technical Highlights

Automatic Hardware Nullification: The NI SCXI – 1520 features automatic hardware nullification, which significantly improves measurement sensitivity and accuracy. Since all strain gauges generate voltage offsets, this module’s ability to automatically remove these offsets (as opposed to manual removal via potentiometers or software in some systems) streamlines the measurement process and reduces errors.

Versatile Strain Measurement Configuration: It supports 10 – wire strain measurements, with two wires dedicated to excitation, two for signal measurement, two for remote sensing, and four for two independent shunt calibration circuits. Remote sensing of the excitation source allows for monitoring the actual value at the strain gauge bridge, ensuring accurate excitation voltage and thus better measurement precision. Shunt calibration enables users to electrically simulate a known strain on the module, facilitating system gain calibration and guaranteeing accurate measurements.

Programmable Channel Features: All features of each channel, including gain, excitation level, and low – pass filter cut – off frequency, can be programmed using NI – DAQ driver software. This programmability provides users with the flexibility to fine – tune the module’s performance according to the specific requirements of their applications. Additionally, the module comes equipped with an onboard calibration reference and a NIST – traceable calibration certificate, ensuring reliable and accurate measurements.

High – Speed Data Acquisition: With a maximum sampling rate of 250 kS/s per channel (multiplexed), the NI SCXI – 1520 is capable of capturing fast – changing signals, making it suitable for applications where real – time monitoring and control are essential. Its high – speed performance, combined with 16 – bit resolution, ensures that even subtle signal details are accurately captured.

Built – in Signal Conditioning: Each channel is equipped with a programmable 4 – pole Butterworth filter that offers a sharp cut – off to eliminate noise while maintaining the highest flatness in the passband. This filter, along with the module’s high input impedance (1 MΩ in differential mode), helps to minimize loading effects on the signal source and preserve signal integrity.

4. Typical Application Scenarios

Industrial Process Monitoring: In manufacturing plants, the NI SCXI – 1520 can be used to monitor the stress and strain on machinery components, such as conveyor belts, robotic arms, and machine shafts. By connecting to strain gauges attached to these components, the module can provide real – time data on mechanical stress, allowing for predictive maintenance and preventing costly equipment failures. For example, in a metal stamping factory, the module can monitor the strain on the stamping dies, alerting operators when the dies are approaching their fatigue limit.

Structural Health Monitoring: In civil engineering, the module is valuable for monitoring the structural integrity of bridges, buildings, and other large – scale structures. When connected to strain gauges and accelerometers placed at critical points on these structures, the NI SCXI – 1520 can measure minute vibrations and stress levels. In a bridge monitoring system, it can detect early signs of structural fatigue by measuring micro – strains in the bridge’s support beams, providing valuable data for infrastructure maintenance and safety assessment.

Automotive Testing: During automotive component testing, the module plays a crucial role in measuring forces, torques, and pressures. For instance, in an engine test cell, it can connect to torque sensors on the engine’s crankshaft to measure the torque output accurately. In a brake testing facility, it can monitor the pressure in the brake lines and the strain on the brake calipers, ensuring the safety and performance of automotive braking systems.

Research and Development: In academic and industrial research labs, the NI SCXI – 1520 is used for experiments that require precise measurement of low – level signals. For example, in a materials science research project studying the mechanical properties of new composite materials, the module can be used to measure the strain on test specimens under different loading conditions. Its high – resolution measurements and programmable features make it an ideal tool for researchers to obtain accurate and reliable data for scientific analysis.

NI SCXI-1520

5. Related Model Recommendations

SCXI – 1000: A 13 – slot SCXI chassis that provides the necessary power and backplane communication for the NI SCXI – 1520. It can house multiple SCXI modules, allowing for the expansion of a data acquisition system to meet the requirements of complex applications.

SCXI – 1314: A screw terminal block that interfaces between the NI SCXI – 1520 and field sensors. It features screw terminals for secure wiring connections and is designed to work seamlessly with the module.

PXI – 6224: A multifunction DAQ module that can be used in conjunction with the NI SCXI – 1520 (through an appropriate interface) to digitize the conditioned analog signals for further analysis and storage. It offers a wide range of analog and digital I/O capabilities, making it a versatile choice for data acquisition systems.

LabVIEW: NI’s graphical programming software is highly compatible with the NI SCXI – 1520. It provides an intuitive environment for configuring the module, visualizing real – time data, and implementing data analysis algorithms. LabVIEW’s extensive library of functions and tools simplifies the development of data acquisition and control applications.

SCXI – 1127: Another 8 – channel isolated analog input module from NI. While it has different signal conditioning capabilities compared to the NI SCXI – 1520, in some applications where isolation and a different set of input ranges are required, it can be used in parallel or as an alternative in a modular measurement system.

TBX – 96: A DIN – rail mounted terminal block that can be used instead of the SCXI – 1314, offering a different form factor for wiring connections in applications where DIN – rail mounting is preferred, such as in industrial control panels.

SCXI – 1521: A related module that may offer different features or performance characteristics. In applications where a different channel configuration or specific measurement requirements are present, the SCXI – 1521 can be considered as an alternative or supplementary module to the NI SCXI – 1520.

6. Installation, Commissioning and Maintenance Instructions

Installation Preparation: Before installing the NI SCXI – 1520, power off the SCXI chassis. Use an anti – static wristband to prevent electrostatic discharge from damaging the module. Verify that the SCXI chassis (such as the SCXI – 1000) is compatible and has an available slot. Inspect the module’s connectors for any signs of damage. Ensure that the chosen terminal block (e.g., SCXI – 1314 or TBX – 96) is appropriate for the application’s voltage, current, and wiring requirements.

Commissioning Steps: Insert the NI SCXI – 1520 into the available slot in the SCXI chassis, and secure it using the front – panel screws. Connect the terminal block to the module using the appropriate cable (compatible with the 68 – pin VHDCI – like interface). Power on the chassis and launch NI Measurement & Automation Explorer (MAX). In MAX, detect the module and configure the channel settings, including input range, single – ended/differential mode, gain, excitation level, and filter cut – off frequency. Use a precision signal generator to perform a calibration of the module, following the procedures outlined in the NI – DAQmx software. After calibration, test the module with a known sensor signal to verify proper signal conditioning and measurement accuracy.

Maintenance Suggestions: Inspect the NI SCXI – 1520 quarterly for loose connections, especially at the module – to – chassis and module – to – terminal – block interfaces. Check for dust accumulation on the module, especially around the ventilation areas, and clean it using compressed air if necessary. Annually, verify the isolation integrity of the module using a megohmmeter to ensure that the channel – to – ground resistance remains above the specified value (e.g., 1 GΩ). If any measurement drift or inaccuracies are observed, recalibrate the module using NI’s calibration software and procedures. Store the module in a dry environment with a temperature range of – 40 °C to 70 °C when not in use.

7. Service and Guarantee Commitment

NI provides a standard warranty for the NI SCXI – 1520 (although the specific duration may vary; some sources indicate 1 year from the date of shipment). During the warranty period, NI will repair or replace the module if it is found to have defects in materials or workmanship, minimizing downtime for users.

The company’s global technical support team offers comprehensive assistance for installation, configuration, and troubleshooting. Support is available through online resources, email, and phone consultations. NI also provides calibration services to maintain the module’s measurement accuracy. Their calibration procedures are often ISO 17025 – accredited, ensuring traceability to international standards. This commitment to quality and support ensures that users can rely on the NI SCXI – 1520 for accurate and consistent signal conditioning and measurement in their applications.