The NI USB-6501 is a compact, bus-powered USB digital I/O device that delivers 24 individually configurable digital lines for data acquisition and control applications. Organized into three 8-line ports, each line operates at 5 V TTL/CMOS logic levels with source currents up to 3 mA per channel (8.5 mA with external pull-up) and sink currents to 8.5 mA per channel. The device integrates a single 32-bit event counter on P2.7/PFI 0, counting falling edges at frequencies up to 5 MHz with 100 ns minimum pulse widths. Full-Speed USB 2.0 connectivity enables plug-and-play operation across Windows, macOS, and Linux platforms. Software-timed signal sampling and updates suit laboratory automation, process control, and hardware testing workflows. The device measures 6.35 cm × 8.51 cm × 2.31 cm without connectors and weighs 84 g, fitting compact benchtop and embedded system integrations.
Technical Specifications
Digital I/O
• 24 single-ended lines organized into three ports: P0., P1., P2.
• Each line independently configurable as input or output
• 5 V TTL/CMOS compatible; input range -0.3 V to 5.8 V
• Output drive: 3 mA source (default), 8.5 mA sink per channel
• Maximum simultaneous source current across all outputs: 65 mA
• Default state: high-impedance inputs at startup and reset
• Software-timed sampling and updates
Counter
• Single 32-bit event counter on P2.7/PFI 0
• Falling edge counting to 5 MHz maximum input frequency
• Minimum pulse widths: 100 ns high, 100 ns low
Power & Electrical
• Input voltage: 4.50 VDC to 5.25 VDC (configured state)
• Active current: 80 mA typical, 500 mA maximum
• +5 V output: 230 mA maximum (4.00 V to 5.25 V range, disabled during USB suspend)
• Suspend current: 500 μA maximum (DIO lines disconnected)
Interface & Connectivity
• Full-Speed USB 2.0 (12 Mbit/s) via Series B receptacle
• Standard connectors: two 16-position screw terminals (16–28 AWG compatible)
• OEM version: 34-pin IDC connector option
• Supports LabVIEW, LabWindows/CVI, and Visual Studio via NI-DAQmx driver
– Key Features
• Individually configurable digital I/O lines
• 32-bit event counter with 5 MHz bandwidth
• Bus-powered operation; no external supply required
• Compact form factor: 84 g, 6.35 cm × 8.51 cm × 2.31 cm
• Screw terminal wiring for field installation
– Typical Applications
• Digital process control and relay actuation
• Switch state monitoring and edge detection
• Event counting in industrial test systems
• Hardware-in-the-loop validation
• Benchtop automation and data logging
– Compatibility & Integration
The USB-6501 integrates with NI-DAQmx drivers across Windows, macOS, and Linux. Development support spans LabVIEW, LabWindows/CVI, and Visual Studio, enabling rapid deployment in academic laboratories, manufacturing, and field test environments.
