The National Instruments VXI-DIO-128 is a 128-channel parallel digital I/O module for VXIbus systems. It provides 64 input and 64 output channels configured as eight 16-bit programmable peripheral interfaces (PPIs) controlled by 82C55A chips. Each PPI reconfigures into two 8-bit ports for flexible channel assignment. The module accepts input signals up to ±42 V with programmable thresholds and -32 to +31.75 V logic threshold range. Digital outputs are open-drain, capable of switching 42 V at up to 250 mA sink current. Input impedance measures 160 kΩ. As a single-slot C-size VXI module, it connects via front-panel 96-pin connectors and is VXI Plug&Play compliant with factory-default logical address 4 and dynamic address reconfiguration support.
Technical Specifications
• Channels: 128 total (64 input, 64 output)
• Architecture: Eight 16-bit PPIs (82C55A chips) expandable to sixteen 8-bit ports
• Digital Input: ±42 V range, -32 to +31.75 V logic threshold, 160 kΩ impedance, programmable threshold voltage
• Digital Output: Open-drain, 42 V switching capability, 250 mA sink current
• Form Factor: Single-slot C-size VXI module
• Connectors: 96-pin front-panel I/O connector
– Key Features
• Eight 82C55A PPI chips (four for input, four for output)
• Reconfigurable 16-bit and 8-bit port mapping
• Wide input voltage acceptance with programmable thresholds
• High-current open-drain outputs
• VXI Plug&Play compliance with dynamic logical address assignment
• NI-DAQ driver software included
– Typical Applications
• Industrial control and relay driving
• Switch signal acquisition
• Laboratory test automation
• Process monitoring and production testing
• Interfacing with panel meters, solid-state relays, LEDs, electromechanical relays, and I/O racks
– Compatibility & Integration
Supported programming environments include LabVIEW, LabWindows/CVI, Measure, ComponentWorks, and VirtualBench. Compatible with WINNT, WIN95, and WIN platforms. NI-DAQ driver software enables straightforward integration into automated test systems.
