The National Instruments PXI-6527 is a 48-channel parallel digital I/O module delivering 24 optically isolated inputs and 24 solid-state relay outputs for PXI systems. Built on the 8255 chipset, this interface handles voltage signals from 0 to 28 VDC with 60 VDC isolation between channels and from the computer, making it ideal for industrial control and data acquisition where electrical noise and ground loops pose risks.
Technical Specifications
-# Digital Inputs
• 24 optically isolated channels
• Input range: 0 to 28 VDC
• Logic levels: 0–1 V (low), 2–28 VDC (high)
• Input current: 1.5 mA maximum at 5 V; 8 mA maximum at 24 V
• Isolation: 60 VDC from computer and between channels
• Differential isolated terminals per channel (signal and reference)
-# Digital Outputs
• 24 solid-state relay channels
• Maximum switching voltage: 60 VDC (30 Vrms)
• Maximum switching current: 120 mA
• Isolation: 60 VDC from computer and between channels (30 Vrms)
• Power-up state: Open (high) by default; individually configurable
• Output logic: Low closes connection; high opens connection
-# General
• Bus interface: PXI
• Total channels: 48
• Chipset: 8255
– Key Features
• Change notification generates messages on user-selected input transitions (rising, falling, or both), eliminating constant polling and reducing CPU overhead.
• Debouncing filter eliminates glitches and spikes on input lines, preventing erroneous state changes.
• Flexible output control sources or sinks current depending on external load configuration; external pull-up resistors and isolated supplies support either mode.
• TTL and non-TTL compatibility across both input and output channels.
• Channel isolation protects the PXI system from external signal damage while reducing noise.
– Typical Applications
Industrial control systems, relay switching, equipment monitoring, test automation, laboratory signal interfacing, and noise-sensitive measurement environments.
