Product Short Description
Product Introduction
The NI-9215 is a 4-channel, ±10 V, 16-bit simultaneous analog input module belonging to the National Instruments C Series. It performs differential analog input and includes NIST-traceable calibration. The module features channel-to-earth ground isolation for safety, noise immunity, and extended common-mode voltage range. It is available in screw-terminal, spring-terminal, and BNC configurations.
Description
Technical Specifications
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Number of Channels: 4 differential analog input channels
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ADC Resolution: 16 bits, SAR (Successive Approximation Register) type
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Input Range: ±10.0 V (measurement voltage, AI+ to AI−)
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Overvoltage Protection: ±30 V
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Conversion Time: 4.4 µs (Ch0 only) to 10 µs (all 4 channels)
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Input Bandwidth (−3 dB): 420 kHz minimum
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Input Impedance: 1 GΩ (screw/spring terminal), 200 kΩ (BNC)
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CMRR (at 60 Hz): 73 dB minimum
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Accuracy (calibrated, max −40 °C to 70 °C): 0.2% of reading + 0.082% of range
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Gain Drift: 10 ppm/°C; Offset Drift: 60 µV/°C
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Crosstalk: −80 dB
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Isolation: Channel-to-channel none; Channel-to-earth ground 250 V RMS continuous (Measurement Category II) for screw/spring; 60 V DC (Cat I) for BNC
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Power Consumption: 560 mW maximum active; 25 µW sleep
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MTBF: 1,167,174 hours at 25 °C
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Operating Temperature: −40 °C to 70 °C
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Weight: 150 g (screw), 138 g (spring), 173 g (BNC)
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Safety Certification: Class I, Division 2, Groups A–D, T4; Class I Zone 2, Ex nC IIC T4
Functional Features
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Simultaneous sampling across all 4 channels via independent track-and-hold amplifiers.
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Signal buffered and conditioned by an instrumentation amplifier before 16-bit ADC conversion.
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Hot-swappable within supported CompactDAQ or CompactRIO chassis.
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Screw-terminal version accepts 0.2–2.5 mm² wire; spring-terminal version supports ferrules.
Application Scenarios
Used in test and measurement systems for differential voltage acquisition, industrial data logging, and embedded control applications where ±10 V analog signals must be captured with high accuracy and channel-to-ground isolation.
Working Principle
Each of the four differential inputs passes through an overvoltage protection stage and an instrumentation amplifier. The amplified signal is sampled simultaneously by its own track-and-hold circuit and converted by a shared 16-bit SAR ADC. Digitized data is transferred to the chassis backplane with channel-to-earth isolation.
Installation Requirements
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Insert module into a compatible NI C Series chassis (CompactDAQ, CompactRIO, sbRIO).
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For screw-terminal: torque to 0.5–0.6 N·m; strip 13 mm of insulation.
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For spring-terminal: strip 10 mm; insert one or two wires (with 2-wire ferrule).
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Secure connector with screw flanges at 0.2 N·m torque.
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Connect hazardous voltages only to the screw-terminal version; never to BNC version.
Usage Precautions
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Do not connect signals exceeding ±30 V to any channel.
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Never use the BNC version for hazardous voltage (defined as >42.4 Vpk or 60 V DC).
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Do not disconnect I/O wires or remove modules in hazardous locations unless power is off.
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Avoid Measurement Categories III or IV environments.
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Ensure wiring is performed by qualified personnel per local electrical codes.
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