The NI FP-SG-140 is an 8-channel strain gauge analog input module that delivers high-accuracy DC measurements from full-bridge, half-bridge, and quarter-bridge strain gauge sensors, load cells, force sensors, and torque transducers. It integrates bridge completion and programmable excitation directly on each channel, eliminating external signal conditioning and reducing system complexity. The module scales measurements onboard and reports results in mV/V, enabling immediate integration into FieldPoint and Compact FieldPoint control and monitoring systems.
Technical Specifications
• Channels: 8 analog inputs
• Input Ranges: ±3.5 mV/V, ±7.5 mV/V, ±30 mV/V, ±60 mV/V with 12% overranging capability
• Converter: 16-bit delta-sigma ADC with integrated low-pass filter per channel
• Update Rates: 0.87 Hz, 1.11 Hz (rates vary with filter settings)
• Noise Filtering: Configurable low-pass filter—15 Hz, 60 Hz, 240 Hz per channel
• Input Impedance: 20 MΩ
• Excitation Voltage: User-selectable 2.5 V, 5 V, or 10 V per channel; pulsed to reduce self-heating
• Excitation Current: Up to 21 mA per channel
• Bridge Completion: Programmable for full- and half-bridge configurations
• Isolation: 2,300 Vrms optical bank isolation between I/O and inter-module communication bus; no channel-to-channel isolation
• Calibration: NIST-traceable certificate included
• Connections: Screw terminals
• Power: Supplied by FieldPoint terminal base with onboard distribution bus
– Key Features
• Built-in bridge completion eliminates external components for full- and half-bridge measurements
• Programmable excitation voltage and current per channel accommodate varying sensor impedances and operating requirements
• Onboard signal scaling and linearization reduce software overhead and latency
• Configurable low-pass filtering on each channel addresses noise across 15 Hz to 240 Hz range
• Span error compensation up to 12% through overranging capability
• Onboard diagnostics detect module and wiring faults
• High input impedance (20 MΩ) minimizes loading effects on bridge circuits
– Typical Applications
• Structural health monitoring and load measurement
• Pressure and force transducer integration
• Torque and strain data acquisition in test stands
• Field-mounted condition monitoring systems
– Compatibility & Integration
The FP-SG-140 integrates with National Instruments FieldPoint and Compact FieldPoint systems via the inter-module communication bus.
