The USB-ERB24 is a 24-channel electromechanical relay interface device that delivers computer-controlled switching via USB 2.0 full-speed connectivity. Each of the 24 Form C (SPDT) relays independently exposes Normally Open, Normally Closed, and Common terminals through screw connections, enabling flexible circuit integration across automation, control, and laboratory applications. Relays are organized in two 8-channel banks and two 4-channel banks, each bank independently configurable for logic polarity (invert/non-invert) and power-on state (pull-down/pull-up) via onboard switches.
Technical Specifications
Relay Performance
• 24 Form C (SPDT) relays rated 6 A at 240 VAC or 28 VDC
• Maximum switching voltage: 240 VAC, 28 VDC
• Contact resistance: 100 mΩ maximum (initial)
• Operate time: 10 ms maximum; Release time: 5 ms maximum
• Life expectancy: 10 million mechanical operations minimum
• Dielectric isolation (relay contacts): 300 VAC, 50/60 Hz, 1 minute
• Dielectric isolation (PCB output lines): 500 VAC, 50/60 Hz, 1 minute
Power and USB
• USB input: 4.75 V to 5.25 V DC, 10 mA maximum draw
• External power input: 6.0 VDC to 12.5 VDC (nominal 9 VDC)
• Recommended supply: 9 VDC, 3 A regulated power supply
• Typical power consumption: 820 mA (all relays ON, 100 mA downstream); 200 mA (all relays OFF)
• Maximum power consumption: 900 mA (all relays ON, 100 mA downstream); 230 mA (all relays OFF)
• External power output (daisy-chain): 4.0 A maximum; voltage drop: 0.5 V maximum
Control
• Per-bank logic polarity selection: non-invert (0 = not energized) or invert (0 = energized)
• Per-bank power-on configuration: pull-down (relays de-energized) or pull-up (relays energized)
• Switch settings readable via software
– Key Features
• USB Type-B connector for direct computer integration
• Four independently configured relay banks
• Screw terminal connectivity for all relay contacts
• User-configurable relay behavior without firmware updates
• Low USB bus current draw enables hub-compatible operation
– Typical Applications
Automation systems, laboratory instrument control, switched-load testing, process control, and multi-channel signal routing in data acquisition environments.
– Compatibility & Integration
USB 2.0 full-speed operation. Daisy-chain capability via external power output. Compatible with downstream hub devices drawing up to 100 mA.
