NI-9237 24 Bit Strain/Bridge Input Module

This NI-9237 24 Bit Strain/Bridge Input Module integrates complete signal conditioning capabilities and can simultaneously provide excitation and measurement for up to four bridge sensors, enabling strain or load measurements with zero phase delay between channels.

The module features 60 VDC channel continuous isolation to ground and 1,000 Vrms transient isolation, providing high common-mode noise suppression and enhanced safety for operators and test systems. The NI-9237 supports built-in excitation programming for half-bridge and full-bridge sensors, offering both RJ-50 and DSUB interface options. Four RJ-50 connectors allow direct connection to most torque or load cells, enabling customized cable solutions with minimal tooling.

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Description

The NI-9237 belongs to NI's C-Series module product line, which includes over 100 modules covering measurement, control, and communication applications. The core design principles of the C-Series modules are: measurement-specific signal conditioning, multiple isolation options (inter-group/inter-channel/channel-to-ground), a wide temperature range of -40 °C to 70 °C, and hot-swappable support.

The Key Parameter- NI-9237 24 Bit Strain/Bridge Input Module

NI offers three synchronous bridge modules for strain/bridge measurement

The NI-9237 is the model with the highest sampling rate and the most flexible bridge configuration in the series, making it suitable for strain and load measurement environments that require high speed and wide bandwidth.

Advantages of The NI-9237

• High-precision synchronous measurement

Each channel is equipped with an independent 24-bit Delta-Sigma ADC and input amplifier, supporting simultaneous sampling of all four channels and eliminating inter-channel phase delay. Phase nonlinearity is less than 0.001° in the 0 to 1 kHz frequency band, and typical inter-channel gain matching is only 0.15%.

• Flexible bridge configuration

It supports three bridge configurations: full-bridge, half-bridge, and quarter-bridge. Half-bridge and full-bridge completions are implemented internally, while quarter-bridge completion requires external components. The internal half-bridge completion has a typical tolerance of ±1,200 µV/V and a drift of 1.5 µV/V/°C.

• Programmable excitation voltage

It offers four selectable internal drive voltages: 2.5 V, 3.3 V, 5.0 V, and 10.0 V, with a maximum internal drive power of 150 mW. When the internal drive power is insufficient, it supports external drive voltage inputs from 2 V to 10 V. The NI-9237 will automatically reduce the internal drive voltage to keep the total power below 150 mW.

• Remote sensing and shunt calibration

The module offers remote sensing, which continuously and automatically compensates for gain errors caused by resistance in the excitation wire; the shunt calibration function uses a 100 kΩ precision resistor and software-controlled switches to simulate a known strain input and correct gain errors throughout the measurement path.

• TEDS Smart Sensor Support
• High reliability isolation and protection

Channel-to-ground isolation 60 VDC (Measurement Category I), withstand voltage 1,000 Vrms (5-second dielectric withstand voltage test), overvoltage protection between any terminals ±30 V. Common-mode rejection ratio to ground up to 140 dB (0–60 Hz), CMRR for EX− is 85 dB (0–1 kHz).

The NI-9237 can do:

• Strain measurement

The core function of the NI-9237 24 Bit Strain/Bridge Input Module is high-precision strain measurement, supporting full-bridge, half-bridge, and quarter-bridge strain gauge connections. Its 24-bit ADC and ±25 mV/V input range provide exceptional resolution and sensitivity, suitable for a wide range of measurement needs, from microscopic strain to macroscopic structural deformation.

• Load/force/torque measurement

The NI-9237 enables precise measurement of load, force, and torque directly using bridge load cells and torque sensors. Four RJ-50 connectors provide plug-and-play connectivity with most torque and load cells.

• Pressure measurement

When paired with a bridge-type pressure sensor, the NI-9237 enables high-precision pressure measurement, suitable for industrial applications such as hydraulic system monitoring and pipeline pressure testing.

• Offset Null, Shunt Calibration, Remote Sensing, TEDS Auto-Configuration
• Inter-module synchronization

The NI-9237 can be synchronized with NI-9225, NI-9229, and other NI-923x modules. Precise synchronization of data rates across multiple modules is achieved by sharing a master time base (a 12.8 MHz internal time base that can be exported or accept an external time base).

Physical Properties

Compliance and Security Information

Customization

We get it that standard arrangements do not continuously meet one of a kind prerequisites. Our experienced building group gives comprehensive OEM/ODM customization administrations. Whether you require adjusted recurrence ranges, specialized activating alternatives, or custom frame components, we work closely with you to create the idealize arrangement. Our adaptable plan approach guarantees your particular application needs are completely tended to whereas keeping up our quality standards.

FAQs:

✅What is remote sensing? Do I have to connect these two wires?

A: 

• Connecting is strongly recommended. When the sensor cable is long, the wire resistance can cause the actual excitation voltage across the sensor to be lower than the module's output voltage, resulting in measurement errors.

• The remote sensing (Sense+ / Sense-) consists of two independent voltage feedback lines used to measure the true voltage at the sensor terminals in real time. The module automatically and dynamically compensates for voltage drops caused by the wires.

• If the cable is short (< 3 meters), the long wire can be omitted, but Ex+ must be shorted to Sense+ and Ex- to Sense- at the module terminals; otherwise, the software may report errors or the readings may drift significantly.

✅What is the sampling rate of the NI-9237? Can it be used to measure dynamic shock or vibration?

A:

Yes. ​​​​​​​

• Its maximum sampling rate is up to 50 kS/s/ch (50,000 samples per second per channel)

• It uses a 24-bit Delta-Sigma analog-to-digital converter (ADC), with all four channels fully synchronized (simultaneous sampling).

• With its 50 kS/s speed, it can measure not only static dynamic weighing but is also ideal for measuring high-frequency dynamic strain/stress signals from events such as car collisions, explosive impacts, and metal fatigue crack propagation.

✅Why is my channel not connected to any sensors, yet the software readings are fluctuating wildly, even displaying the maximum value?

A:

The NI-9237 is a high-sensitivity, high-impedance microvolt-level measurement module. If a channel is left floating (without a sensor connected), the input may absorb electromagnetic noise from the surrounding environment or reach saturation. This is normal. Before testing, ensure the sensor is correctly wired, or connect a shorting resistor to an unused channel.

✅How to convert the read "voltage signal (V/V)" into real "microstrain (Microstrain)" in LabVIEW?

A:

• There's no need to write complex Wheatstone bridge formulas yourself.
• When creating a DAQmx virtual channel, directly select 'AI Strain' (not AI Voltage) as the signal type.

• In the configuration window, enter the strain gauge sensitivity factor, unstressed resistance (e.g., 350Ω), and the selected bridge type (e.g., type I, II, or III full-bridge/half-bridge). The DAQmx driver layer will automatically convert the microvolt-level V/V differential signal into engineering-standard micro-strain in real time at the lower level and output it directly.

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Contact Us

Ready to integrate reliable Strain/Bridge module control into your system? Our team is here to help you select the right configuration and provide ongoing support.

Contact our technical specialists at manager03@mxtdinfo.com  / manager02@mxtdinfo.com for detailed specifications, pricing information, or to discuss your custom requirements. We're committed to delivering the perfect NI-9237 24 Bit Strain/Bridge Input Module solution for your application needs.