The NI PXIe-7856R is an R Series Reconfigurable I/O Module designed for PXI Express systems, offering a versatile solution for various measurement and control applications. This module integrates analog input (AI), analog output (AO), and digital input/output (DIO) capabilities, all powered by a Kintex-7 160T FPGA, allowing for high-performance and custom-defined operations.
Function Description:
The core function of the NI PXIe-7856R is to provide flexible and reconfigurable I/O for PXI Express platforms. It acts as a bridge between the physical world and the digital processing capabilities of an FPGA, enabling users to implement custom hardware-timed control, high-speed data acquisition, and signal generation. The module's reconfigurable nature, driven by the Kintex-7 FPGA, allows for user-defined logic and parallel processing, making it suitable for applications requiring deterministic behavior and high throughput.
The module features eight analog input channels, each with AI+, AI-, and AIGND pins. This configuration supports both single-ended and differential voltage signals. For referenced single-ended signals, the voltage ground signal must be connected to AIGND to maintain the common-mode voltage within the specified range. For non-referenced single-ended signals, the voltage ground signal should be connected to AISENSE. The AISENSE pin serves as a reference connection for NRSE (Non-Referenced Single-Ended) measurements. Differential voltage signals can be connected as either grounded or floating. Grounded differential signals require the signal reference to be connected to AIGND. Floating differential signals necessitate connecting both positive and negative signals to AIGND through 1 MΩ resistors to keep the voltage within the common-mode range. Overvoltage protection is integrated into the AI channels to safeguard the device.
Analog Output (AO):
The NI PXIe-7856R includes eight analog output channels, each with an AO pin and an AOGND pin. These channels are designed to connect to a load, allowing for the generation of analog signals. AOGND provides the ground reference for the analog output signal.
The module offers a total of 48 digital input/output channels, distributed across two connectors: Connector 0 (MIO) and Connector 1 (DIO).
- Connector 0 (MIO): Contains 16 low-speed DIO channels capable of operating at signal frequencies up to 10 MHz.
- Connector 1 (DIO): Contains 32 high-speed DIO channels capable of operating at signal frequencies up to 80 MHz.
Both sets of DIO channels feature selectable logic levels, configurable as 1.2 V, 1.5 V, 1.8 V, 2.5 V, or 3.3 V. Each channel can be configured individually as either an input or an output. The DIO channels are connected to the FPGA through buffers, which provide overvoltage, undervoltage, and overcurrent protection. Upon system power-on, the DIO channels are set as input low with pull-down resistors. Users can configure the module to load a VI (Virtual Instrument) at power-on to define a different initial state for the DIO lines. High-speed DIO channels on Connector 1 are routed with a 50 Ω characteristic trace impedance, emphasizing the importance of matching external circuitry impedance for optimal signal quality.
Important Technical Specifications:
- Module Type: R Series Reconfigurable I/O Module
- Form Factor: PXI Express
- Analog Input Channels: 8
- Analog Output Channels: 8
- Digital I/O Channels: 48 (16 low-speed, 32 high-speed)
- Analog Input Sample Rate: 1 MS/s
- FPGA: Kintex-7 160T
- Low-Speed DIO Frequency: Up to 10 MHz (Connector 0)
- High-Speed DIO Frequency: Up to 80 MHz (Connector 1)
- DIO Logic Levels: Selectable (1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V)
- External Clock Input (EXTCLKIN): For source synchronous acquisitions, requiring a stable and glitch-free clock source.
- Power Output: +5 Vout (referenced to DGND) for external devices, with a power rating of 4.75 to 5.1 VDC at 0.5 A.
- Protection: Overvoltage and overcurrent protection on DIO channels; overvoltage protection on AI channels.
Usage Features:
- Reconfigurability: The Kintex-7 FPGA allows users to implement custom digital logic, enabling tailored solutions for specific application requirements. This includes custom timing, triggering, and data processing.
- Flexible Signal Connections: Supports various analog input configurations (referenced single-ended, non-referenced single-ended, grounded differential, floating differential) and digital I/O configurations (input/output, selectable logic levels).
- High-Speed Capabilities: High-speed DIO channels (up to 80 MHz) are suitable for applications requiring fast digital communication and control.
- Custom Engineering: The module supports custom engineering to ensure equipment operates exactly as specified, catering to unique project demands.
- Comprehensive Connectivity Options: A range of connection accessories and cables are available to facilitate access to I/O signals, including shielded connector blocks (SCB-68 HSDIO, SCB-68A) and shielded cables (SHC68-C68-RDIO2, SHC68-68-RMIO) for both DIO and MIO connectors.
- Power-On State Configuration: DIO channels can be configured to a specific power-on state by loading a VI, providing control over initial system conditions.
Maintenance Features:
- Robust Protection: Integrated overvoltage, undervoltage, and overcurrent protection on DIO channels, and overvoltage protection on AI channels, enhance the device's durability and reduce the risk of damage from improper connections or signal anomalies.
- Field Wiring Considerations: Recommendations for field wiring, such as using differential AI connections, individually shielded twisted-pair wires, and careful signal routing, help minimize noise pickup and maximize measurement accuracy, contributing to reliable operation and reduced troubleshooting.
- Documentation and Support: Comprehensive user manuals and online resources (ni.com/manuals, ni.com/support) provide detailed information on compliance, pinout, connectivity, mounting, power, device specifications, troubleshooting, and application development.
- Repair and Services: Artisan Technology Group offers full-service, independent repair with experienced engineers and technicians. National Instruments also provides repair services, extended warranty options, and technical support through various channels, including phone and email assistance.
- Asset Management: Artisan Technology Group facilitates the acquisition of pre-owned equipment and offers solutions for excess, underutilized, and idle equipment through buybacks and trade-ins, supporting sustainable asset management.
- ITAR-Certified Solutions: The availability of ITAR-certified secure asset solutions indicates adherence to strict regulatory requirements for handling sensitive technology, ensuring secure and compliant operations for relevant applications.
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