I. Product Introduction

NI SCXI-1141 is an 8-channel differential elliptical low-pass filter amplification module for the SCXI platform. It focuses on high-performance anti-aliasing and precise signal conditioning and has been discontinued (End of Life). It integrates an 8th-order elliptical filter and a programmable gain amplifier. Channels can be synchronized for acquisition, suitable for high-frequency noise suppression, anti-aliasing, and general amplification scenarios. It is often used in conjunction with the SCXI-1305 terminal block.

II. Model Interpretation

SCXI: Signal Conditioning Extension for Instrumentation, a series of instrument signal conditioning extensions.

1141: The product's unique model, representing an 8-channel elliptical low-pass filter amplification module; the 1142 model in the same series represents a Bessel filter, and the 1143 model represents a Butterworth filter.

Standard part number: 776572-41.

III. Technical Parameters

Channel Configuration: 8 differential inputs, single-channel analog-to-digital conversion, multi-channel time-division multiplexing.

Input Range: Software selectable: ±50 mV, ±500 mV, ±5 V, ±10 V.

Filter: 8th-order elliptical low-pass, adjustable cutoff frequency from 10 Hz to 100 kHz (all channels have the same frequency), attenuation 135 dB per octave; supports software bypass for single-channel filtering.

Gain: Software programmable: 1, 2, 5, 10, 25, 50, 100, 200, 500, 1000 times.

Sampling Rate: System maximum 333 kS/s.

Input Impedance: ≥1 MΩ (differential).

Isolation: Channel - Backplane 250 Vrms (CAT II).

Power Consumption: Approximately 2.3 W (±15 V power supply).

Operating Temperature: 0 - 55℃; Storage - 40 - 85℃.

Calibration: Factory calibration, non-volatile storage of calibration constants.

IV. Interface and Communication Configuration

Front Panel: 50-pin SCSI-II connector, compatible with the SCXI-1305 terminal block (screw wiring, supports differential / single-ended).

Backplane Bus: SCXI standard bus, responsible for power supply, control, and data transmission, supports multi-module cascading.

Trigger: External TTL trigger input, supports multi-module synchronous sampling.

Driver and Software: Compatible with NI-DAQmx, supports LabVIEW, LabWindows/CVI, C/C++, .NET; no independent communication port, relies on the SCXI bus and backend DAQ devices for communication.

V. Core Functions

8-channel Precise Filtering Amplification: The elliptical filter provides steep roll-off, effectively anti-aliasing, and suppressing high-frequency noise, with programmable gain suitable for weak signals.

Flexible Filter Configuration: Cutoff frequency software programmable, single-channel can be bypassed for filtering, suitable for different bandwidth requirements.

Multi-channel Synchronous Acquisition: Bus cascading and external trigger synchronization, minimal timing error between channels, suitable for dynamic signal testing.

High Anti-interference Design: 250 Vrms isolation, ±30 V overvoltage protection, suitable for industrial strong interference environments.

System Expansion: Multi-module cascading to expand the number of channels, and mixed construction with modules such as SCXI-1140 to build various types of signal conditioning systems.

VI. Application Scenarios

Vibration / Noise Testing: Mechanical equipment vibration, acoustic measurement, anti-aliasing filtering ensures the accuracy of high-frequency signal acquisition.

Low-level Signal Conditioning: Thermocouples, strain gauges, photoelectric sensors, etc., weak signal amplification and noise suppression.

High-speed Data Acquisition: Required high sampling rate and strong anti-aliasing capability for dynamic tests (such as impact, transient signals).

Industrial Process Monitoring: Multi-channel analog signal acquisition in strong interference environments, such as motor monitoring, production line signal conditioning.

General Signal Filtering: Preprocessing scenario for signals requiring steep low-pass filtering in scientific research and industrial testing.

VII. Usage and Maintenance Instructions

Usage Instructions

Installation: Power off, insert into the SCXI chassis slot, and tighten the fixing screws; when cascading multiple modules, plan the addresses to avoid conflicts.

Connection: Select the SCXI-1305 terminal block, connect the positive and negative ends of differential signals, and single-ended ground the shielding layer.

Configuration: Set the input range, gain, and filter cutoff frequency through NI-DAQmx; configure external trigger when synchronizing acquisition.

Power On: Check the wiring is correct before powering on, turn on the chassis power first and then start the acquisition software; avoid hot-plugging modules.

Maintenance Instructions

Environment: Maintain ventilation and dryness, keep away from strong electromagnetic radiation, vibration, and high temperatures; the working humidity should be 5% to 95% without condensation.

Regular Inspection: Inspect the terminal block, connectors, and cables monthly, clean dust, tighten the connections, and prevent oxidation and loosening.

Calibration: Calibrate once a year to ensure accuracy; calibration should be performed by professionals or by an NI authorized institution.

Fault Troubleshooting: Check the filtering parameters, grounding, and shielding when the data noise is high; check the module installation, bus connection, and driver configuration when there is no signal.

Storage: Power off and disconnect the lines when not in use, clean and store in a cool and dry place to avoid moisture and corrosion.