The Tektronix VX4287 is a 32-channel differential analog/digital input module for VXIbus systems. This single-width, C-size module configures under program control as 32 digital inputs, 32 comparator inputs with time tagging, or 16 analog and 16 digital inputs combined. Each channel supports individually programmable threshold voltages, active high/low logic selection, and channel isolation control. The module delivers flexible signal acquisition with two input voltage ranges, analog comparator triggering, digital strobe and arm capabilities, and debounce filtering across grouped channels.
Technical Specifications
Input Configuration
• 32 differential inputs, independently configurable
• Input voltage ranges: ±25 V (12.5 mV resolution, 125 mV accuracy) and ±50 V (25 mV resolution, 200 mV accuracy)
• Autorange per channel to most sensitive range
• Input impedance: 100 kΩ (both + and − inputs)
• Maximum input voltage: ±150 V (+ input), 80 V (− input)
• Common mode voltage: ±50 V and ±25 V programmable; protected to ±90 V
• CMRR: > 50 dB
Analog Comparator Mode
• Programmable trigger conditions (greater than or less than threshold)
• Per-channel hysteresis = half voltage range magnitude
• Time tagging on comparator events
Digital Input Mode
• TTL-compatible logic thresholds
• Arm/Strobe input: 50 ns minimum pulse width, programmable polarity
• Two debounce counters: Counter 1 (channels 0−7, 16−23); Counter 2 (channels 8−15, 24−31)
• TTLTRG* trigger assertion per VXIbus Synchronous Trigger Protocol
– Key Features
• Single-width, C-size form factor fits C-size or larger VXIbus mainframes
• Per-channel programmable threshold and logic sense
• Individual channel isolation under program control
• Firmware version 1.00 and above compatible
– Typical Applications
• Multi-channel signal conditioning and acquisition in automated test systems
• Mixed-mode signal monitoring with simultaneous analog and digital capture
• Trigger and timing synchronization in VXIbus instrument clusters
– Compatibility & Integration
Conforms to VXIbus Specification. Operates in C-size and larger VXIbus mainframes.
