NI SCXI-1141

Description

Detailed parameter table

NI SCXI-1141

Product introduction

The National Instruments SCXI-1141 is a high-performance 16-channel isolated analog input module, engineered to condition and protect sensitive measurement systems from high-voltage transients and electrical noise in industrial environments. As a critical component of NI’s SCXI signal conditioning ecosystem, it is designed to integrate seamlessly with SCXI chassis like the NI SCXI-1000, providing robust isolation and precise signal amplification for low-level analog signals from sensors, transducers, and industrial equipment.

Ideal for applications requiring measurement integrity in noisy or high-voltage environments, the NI SCXI-1141 offers 2,500 Vrms isolation between channels, chassis, and ground—eliminating ground loops and protecting DAQ devices from voltage spikes. When paired with the NI SCXI-1000 chassis and compatible DAQ hardware (e.g., NI PCI-6221 via NI SCXI-1349 interface), the NI SCXI-1141 creates a complete measurement chain: it amplifies weak signals (down to ±20 mV) with selectable gains up to 1000x, filters out noise, and routes conditioned signals to the DAQ device for digitization. Its 16-channel design balances density and flexibility, making it suitable for both lab-based testing and industrial monitoring systems.

Core advantages and technical highlights

Industrial-Grade Isolation for Signal Integrity:
The NI SCXI-1141’s 2,500 Vrms isolation is its defining feature, providing a critical barrier between high-voltage industrial environments and sensitive DAQ equipment. This isolation eliminates ground loops—common in factory floors with multiple grounded devices—by electrically separating each channel from others and the chassis. Unlike non-isolated modules, the NI SCXI-1141 can safely measure signals in systems with large ground potential differences (up to 2,500 V), such as power distribution panels or motor control cabinets. For example, in a manufacturing plant monitoring 16 motor current sensors, the NI SCXI-1141 prevents voltage transients from motor startups from damaging the NI SCXI-1000 chassis or connected DAQ device.

Precision Amplification and Wide Dynamic Range:
With software-selectable gains (1 to 1000x) and input ranges (±20 mV to ±20 V), the NI SCXI-1141 adapts to diverse signal types—from millivolt-level strain gage outputs to volt-level pressure transducer signals. Its ±0.01% typical accuracy ensures measurements remain reliable across all ranges, while the 10 GΩ input impedance minimizes loading on signal sources (critical for high-impedance sensors like pH probes). In a structural testing lab, for instance, the NI SCXI-1141 can amplify 20 mV signals from strain gages (with gain 1000x) and 10 V signals from load cells (with gain 1x) on the same module, eliminating the need for multiple specialized modules.

Superior Noise Rejection for Clean Measurements:
The NI SCXI-1141 combines high isolation with a 100 dB minimum CMRR (at 50/60 Hz) to reject common-mode noise—electrical interference from nearby motors, transformers, or power lines. This noise rejection is enhanced by the module’s differential input configuration, which amplifies only the difference between signal leads (ignoring noise common to both). When installed in a NI SCXI-1000 chassis with its shielded backplane, the NI SCXI-1141 maintains signal integrity even in environments with electromagnetic interference (EMI), such as near welding equipment or variable frequency drives. This makes it ideal for measuring low-level signals in industrial automation, where noise can otherwise mask critical data.

Scalable Channel Density with Chassis Integration:
The NI SCXI-1141’s 16-channel design maximizes measurement density without sacrificing performance, fitting easily into 4-slot chassis like the NI SCXI-1000 (supporting up to 4 modules for 64 channels total). It leverages the NI SCXI-1000’s backplane for power, timing, and communication, eliminating external wiring and simplifying system expansion. Users can configure channels individually via LabVIEW or NI MAX—selecting ranges, gains, and scanning rates without hardware rework. For example, a water treatment plant monitoring 16 pH sensors can reconfigure 8 channels to measure ±500 mV (pH electrode range) and 8 to measure ±10 V (pump pressure) via software, adapting the NI SCXI-1141 to changing process needs.

Typical application scenarios

In power generation facilities, the NI SCXI-1141 monitors electrical and mechanical parameters in turbine systems. Installed in a NI SCXI-1000 chassis near the turbine control panel, it measures 16 signals: 8 current transformer outputs (±100 mV) from generator windings and 8 temperature transducer signals (±5 V) from bearing housings. The NI SCXI-1141’s 2,500 Vrms isolation protects the measurement system from high-voltage transients in the generator, while its 100 dB CMRR rejects noise from nearby transformers. Data from the NI SCXI-1141 is sent to a NI PCI-6221 DAQ card for real-time analysis, enabling early detection of bearing overheating or winding faults—preventing costly turbine shutdowns.

In automotive manufacturing, the NI SCXI-1141 is used in end-of-line testing for electric vehicle (EV) batteries. Mounted in a NI SCXI-1000 chassis integrated into a test station, it measures 16 battery cell voltages (±5 V) and 8 temperature sensor outputs (±100 mV) during charging cycles. The module’s isolation prevents ground loops between the battery pack (floating ground) and the test station (earth ground), while its precision (±0.01% accuracy) ensures cell voltage differences as small as 1 mV are detected—critical for identifying faulty cells. LabVIEW software logs data from the NI SCXI-1141, generating pass/fail reports that ensure only quality batteries reach customers.

In chemical processing, the NI SCXI-1141 monitors process variables in hazardous areas. Housed in an explosion-proof enclosure with a NI SCXI-1000 chassis, it measures 16 signals: 8 pH sensor outputs (±500 mV) from reaction vessels and 8 pressure transducer signals (±10 V) from pipelines. The NI SCXI-1141’s isolation protects operators and equipment from voltage spikes in the harsh chemical environment, while its high input impedance ensures accurate pH measurements (which require minimal loading). The module’s compatibility with the NI SCXI-1000 allows easy integration with a distributed control system (DCS), enabling real-time adjustments to chemical dosing based on NI SCXI-1141 data—reducing waste and improving product consistency.

NI SCXI-1141

Related model recommendations

NI SCXI-1140: An 8-channel isolated analog input module, serving as a smaller-channel alternative to the NI SCXI-1141. It shares the same 2,500 Vrms isolation, accuracy, and gain options but fits 8 channels—ideal for setups where the NI SCXI-1141’s 16 channels are unnecessary.

NI SCXI-1142: A 32-channel isolated module that upgrades the NI SCXI-1141 for high-density applications (e.g., 32-sensor industrial monitoring). It maintains the NI SCXI-1141’s isolation and accuracy while doubling channel count, suitable for scaling beyond 16 channels.

NI SCXI-1000: The 4-slot SCXI chassis that hosts the NI SCXI-1141, providing power, cooling, and DAQ integration. It is the primary chassis for small to medium systems using the NI SCXI-1141, supporting up to 4 modules (64 channels total).

NI SCXI-1349: A SCXI-DAQ interface module connecting the NI SCXI-1141 (in NI SCXI-1000) to DAQ devices like the NI PCI-6221. It routes conditioned signals from the NI SCXI-1141 to the DAQ device, ensuring signal integrity.

NI PCI-6251: A high-speed DAQ card paired with the NI SCXI-1141 for high-throughput measurements. With 1.25 MS/s sampling rate, it captures fast-changing signals conditioned by the NI SCXI-1141, such as motor current transients.

NI USB-6363: A portable USB DAQ device compatible with the NI SCXI-1141 and NI SCXI-1000 for field testing (e.g., power line monitoring). It enables the NI SCXI-1141 to be used in remote locations without desktop PCs.

NI SCXI-1327: A terminal block accessory for the NI SCXI-1141, providing screw terminals for easy connection of sensors and transducers. It simplifies wiring and protects the module’s connectors from wear.

NI SCXI-1121: A non-isolated 16-channel analog input module that complements the NI SCXI-1141 in mixed environments. While the NI SCXI-1141 handles high-voltage areas, the NI SCXI-1121 is used for low-noise, non-isolated measurements, reducing system cost.

Installation, commissioning and maintenance instructions

Installation preparation

Before installing the NI SCXI-1141 into a NI SCXI-1000 chassis, power off the chassis and use ESD protection (wrist strap, mat) to prevent damage to the module’s sensitive components. Verify the NI SCXI-1000 has an available slot and that its firmware is updated (via NI MAX) to support the NI SCXI-1141. Required tools include a Phillips-head screwdriver (to secure the module) and insulated wire strippers (for sensor wiring). When connecting signals, use shielded twisted-pair cables (24 AWG or larger) and ensure proper grounding of shields at the sensor end to maximize noise rejection. For high-voltage applications, confirm that input signals stay within the module’s ±20 V range to avoid damaging the isolation barrier. Connect the NI SCXI-1000 to a DAQ device via NI SCXI-1349 before powering on to enable module configuration.

Maintenance suggestions

For daily maintenance of the NI SCXI-1141, inspect terminal connections (or NI SCXI-1327 block) weekly for loose wires or corrosion—tighten connections and clean terminals with isopropyl alcohol if needed, as poor contacts degrade accuracy. Calibrate the module annually using a precision signal generator (e.g., NI 4263A) to verify gain accuracy and isolation integrity; this ensures measurements remain within the ±0.01% specification. Monitor the NI SCXI-1141’s performance via NI MAX—unexpected noise or drift may indicate a failing isolation barrier, requiring factory service. When replacing the module in the NI SCXI-1000 chassis, power off the chassis and save channel configurations (ranges, gains) in NI MAX to simplify reconfiguration. Avoid exposing the NI SCXI-1141 to temperatures above 55 °C or excessive moisture, as this can degrade isolation and electronic components over time.

Service and guarantee commitment

National Instruments (NI) backs the NI SCXI-1141 with a 2-year standard warranty, covering defects in materials and workmanship—including the critical isolation barrier and precision amplifiers. If the NI SCXI-1141 fails during the warranty period (e.g., due to isolation degradation or gain inaccuracy), NI provides free repair or replacement, with expedited service for critical industrial applications to minimize downtime. NI’s global technical support team is available 24/7 via email, phone, and chat, offering expertise in configuring the NI SCXI-1141 (e.g., gain selection, noise mitigation), troubleshooting integration with NI SCXI-1000 chassis, and optimizing measurements in high-noise environments. Additionally, NI provides lifetime access to firmware updates, driver downloads, and application notes for the NI SCXI-1141, ensuring compatibility with new SCXI hardware and software. This commitment reflects NI’s confidence in the NI SCXI-1141’s industrial-grade reliability and supports customers in maintaining accurate, long-term measurement systems.