National Instruments NI 9242 4-Channel Analog Input Module for CompactRIO and CompactDAQ

Product Overview

The National Instruments NI 9242 (NI-9242) is a C Series analog input module designed for use with CompactRIO and CompactDAQ systems. This module provides 4 simultaneous-sampling differential analog input channels, each capable of measuring voltages up to 250 V RMS (400 V peak). The NI 9242 is ideal for power monitoring, industrial machine condition monitoring, and energy measurement applications. The module features high-voltage isolation (up to 1000 V DC channel-to-channel) and a wide bandwidth, making it suitable for measuring AC power signals at 50/60 Hz or higher frequencies.

Key Features of NI 9242

The module has a voltage range of ±250 V AC/DC (peak) with a nominal 250 V RMS input. The input impedance is 1 MΩ, minimizing loading on the measured circuit. The NI 9242 includes a 24-bit sigma-delta analog-to-digital converter per channel, providing high resolution and accuracy. The maximum sampling rate is 50 kS/s per channel simultaneously. The module includes anti-aliasing filters and is designed for direct connection to potential transformers or power lines.

The NI 9242 is rated for CAT II (300 V) and CAT I (600 V) measurement categories. It is isolated from the backplane to 300 V RMS working voltage. The module includes LED indicators for channel status and power. It operates from the CompactRIO/CompactDAQ backplane power supply. The operating temperature range is -40 to +70°C. The module is certified for CE, UL, and ATEX/IECEx (Class I, Division 2) for hazardous locations. It is suitable for use in harsh industrial environments.

Technical Specifications

• Manufacturer: National Instruments

• Part Number: NI 9242 (NI-9242)

• Product Type: C Series Analog Input Module

• Number of Channels: 4 (differential, simultaneous sampling)

• Input Voltage Range: ±250 V AC/DC peak (250 V RMS)

• Resolution: 24 bits

• Sampling Rate: 50 kS/s per channel (max)

• Input Impedance: 1 MΩ

• Isolation: 1000 V DC channel-to-channel, 300 V RMS to backplane

• Measurement Category: CAT II (300 V), CAT I (600 V)

• Bandwidth: 50 kHz typical

• Indicators: LED per channel

• Power Supply: 24 V DC from backplane

• Operating Temperature: -40 to +70 °C

• Storage Temperature: -40 to +85 °C

• Degree of Protection: IP20

• Certifications: CE, UL, ATEX/IECEx Class I Div 2

Functional Description

The NI 9242 measures AC or DC voltages up to 250 V RMS directly. Each channel has a dedicated 24-bit ADC, enabling simultaneous sampling of all four channels for accurate power calculations (e.g., real power, RMS voltage, phase angle). The module is typically used with LabVIEW software, which provides function blocks for power analysis. The high isolation allows the module to be used in high-voltage applications without additional signal conditioning. The wide temperature range and hazardous location certification make it suitable for outdoor and industrial environments.

Applications

The NI 9242 is used in power quality monitoring, motor current analysis, industrial energy metering, and predictive maintenance systems. It is also used in research and development for testing electrical equipment.