The Measurement Computing CIO-DIO24H is a high-drive TTL digital I/O board for PCI bus systems, delivering 24 independently programmable lines based on the 82C55 parallel-interface chip. Three configurable ports—two 8-bit (A and B) plus one 8-bit port divisible into two 4-bit sections (C-HI and C-LO)—enable flexible input/output assignment for industrial control, data logging, and automated test applications. All I/O bits initialize to high-impedance input on power-up and reset, with optional SIP resistor networks supporting pull-up or pull-down biasing.
Technical Specifications
• Digital I/O Channels: 24 lines
• Interface Chip: 82C55 (Mode 0 emulation)
• Port Architecture: Port A (8-bit), Port B (8-bit), Port C (8-bit or dual 4-bit)
• Input Type: LSTTL compatible; Input High 2.0 V min to 5.5 V max; Input Low −0.5 V min to 0.8 V max; Input Current ±10 µA
• Output Type: Buffered high-drive TTL (74S244 drivers); Output High 2.4 V min @ −15 mA; Output Low 0.55 V max @ 64 mA; Sink Current 64 mA; Source Current 15 mA
• Power Consumption (+5 V): 400 mA typical, 625 mA maximum
• External Interface: 37-pin male D-type connector
• Interrupt Support: Jumper-selectable IRQ 2–7; rising-edge triggered external input; active-LOW enable
• Form Factor: Half-size PCI card
– Key Features
• Individual port programming for input or output configuration
• Jumper-selectable interrupt routing (IRQ 2–7)
• High input impedance (74LS-equivalent)
• High output drive capability with 74S244 buffers
• SIP resistor network provisions for termination flexibility
– Typical Applications
Industrial automation and control, real-time data logging systems, automated test equipment, and legacy PCI-based laboratory instruments requiring flexible digital switching and monitoring.
– Compatibility & Integration
PCI bus systems with plug-and-play support (Windows 2000, Windows XP). Programmed via InstaCal utility, MCC DAQ software bundle, and Universal Library with full documentation and driver support.
