The Racal Instruments 1261B is a high-performance VXIbus mainframe chassis available in 7U benchtop and 9U rack-mount configurations. It delivers fourth-generation cooling and advanced power delivery to support demanding VXI module installations with superior thermal management and electrical performance.
Technical Specifications
Chassis Configuration
• 7U benchtop format for space-limited applications
• 9U rack-mount format for standard installations
• 13-slot mainframe architecture
Cooling System
• Fourth-generation pressurized plenum cooling—highest capacity of any general-purpose VXI mainframe
• Molded card guides direct airflow through modules front-to-back and side-to-side
• Snap-on covers divert airflow from unused slots
• Three rear-pluggable fans with fault tolerance; two fans maintain high cooling on single-fan failure
• HI/LO cooling switch on basic units to balance noise and reliability
• Variable-speed fan control (with system monitor) adjusts speed based on worst-slot temperature rise
• Maximum cooling selection via rear switch
Power Supply
• Advanced design with minimal ripple and noise; plugs directly into backplane
• High dynamic current capability for crisp waveforms and accurate measurements
• Over-voltage and under-current protection
• 1261B-Linear variant: separate linear power supply for RF and microwave applications with ultra-low noise
• 1261B-Linear available power: 760 W
• 1261B-Linear maximum power consumption: 1130 W
• 1261B-Linear input voltage: 115 Vrms ±10%
• 1261B-Linear input frequency: 47 Hz to 63 Hz
Monitoring Systems
• Optional Standard Monitor System (SMS): automated checks of VXIbus voltages, currents, airflow, and temperature against factory limits; bi-color LED annunciators; independent power rail
• Optional Enhanced Monitoring System (EMS): microcontroller-based with VXIbus message interface, front panel alphanumeric display, individual slot voltage and temperature monitoring; independent power rail
– Key Features
• Independent monitoring power rails—monitoring systems do not consume VXI slots
• Fault-tolerant architecture maintains performance during cooling system failures
• Pressurized plenum design ensures uniform thermal distribution across all module positions
• Linear power supply variant eliminates switching noise for sensitive RF measurements
– Typical Applications
Automated test systems, RF and microwave measurement benches, space-constrained rack installations, production test environments requiring high cooling capacity and low power supply noise.
– Compatibility & Integration
VXIbus-compliant module support across 13 slots. Enhanced monitoring system provides backplane-based reporting and soft front panel interface for system integration.
