The Keysight 34921T is a detachable terminal block designed for the 34921A 40-channel multiplexer and L4421A 40-channel LXI armature multiplexer. It provides screw-type connection points for discrete sensor and signal wiring while incorporating a built-in isothermal thermocouple reference junction to minimize thermal offset errors in temperature measurements.
Technical Specifications
• Switch Rating: 300 V, 1 A
• Carry Current: 2 A
• Wire Size Support: Up to 20 AWG (fewer than 100 connections) or 24 AWG (more than 100 connections)
• Connector Interface: Screw-type terminals with 50-pin D-sub compatibility
• Reference Junction: Built-in isothermal thermocouple reference with temperature sensor located on bottom side of PC board
• Physical Dimensions: Approximately 8 × 8 × 4 inches (1 lb) or 10 × 5 × 3 inches (2 lb)
– Key Features
• Detachable design for flexible external wiring configuration
• Safety interlock shorts specific pins to protect against inadvertent high-voltage routing to the D-sub connector
• Factory labeling includes model number, abbreviated module name, and space for slot number annotation
• Discrete wiring facilitation with screw-terminal connections
– Typical Applications
• Multi-channel thermocouple measurement systems requiring accurate thermal reference compensation
• Multiplexed data acquisition with organized discrete wiring schemes
• Sensor signal conditioning and routing in test and measurement systems
– Compatibility & Integration
The 34921T integrates with the Keysight 34980A mainframe to enable multi-module scanning up to 560 two-wire (differential) channels or 640 one-wire (single-ended) channels. Primary compatibility extends to the 34921A and L4421A multiplexers, with additional support for the 34922A, 34923A, and 34924A multiplexer modules.
