The OMB-DAQ-56 is a USB-powered personal data acquisition module engineered for portable signal capture and real-world measurement tasks. Built around a 22-bit A/D converter, it provides 20 single-ended and 10 differential analog input channels within a compact form factor. Direct thermocouple measurement with integrated cold junction compensation supports eight industry-standard thermocouple types across temperature ranges from -200°C to +1400°C. Powered exclusively from the USB bus, the module requires no external power supplies and communicates via high-speed USB up to 5 m from the host PC. Scalability is inherent—up to 100 modules cascade through USB hubs to deliver 8000 total measurement channels from a single computer.
## Technical Specifications
**Analog Input**
• 22-bit A/D converter resolution
• 20 single-ended input channels
• 10 differential input channels
• Programmable voltage ranges: ±31 mV to ±20 V full scale
• Input resistance: >10 MΩ (single-ended), >20 MΩ (differential)
• Bias current: 120 dB @ 60 Hz
• Channel-to-channel crosstalk: <-120 dB (DC to 100 Hz)
**Thermocouple Measurement**
• Cold junction compensation accuracy: ±0.5°C
• Type J: -100 to 700°C, ±1.1°C
• Type K: -200 to 1200°C, ±1.2°C
• Type T: -100 to 400°C, ±1.1°C
• Type E: -100 to 500°C, ±1.0°C
• Type R: -400 to 1400°C, ±2.5°C
• Type S: 400 to 1400°C, ±2.6°C
• Type B: 700 to 1400°C, ±3.3°C
• Type N: -100 to 700°C, ±1.5°C
**Interface & Power**
• USB connectivity; bus-powered operation
• Optional external supply: 6 to 16 Vdc when using bus-powered hubs
• Maximum cable distance: 5 m (16.4 feet)
• Multi-module capacity: up to 100 modules per PC, 8000 total channels
## Key Features
• Doubles the I/O capacity of the OMB-DAQ-55 in identical physical dimensions
• Direct thermocouple support eliminates external signal conditioning
• High input impedance and low bias current minimize loading effects
• Exceptional channel isolation and common-mode rejection
• Zero external power infrastructure required
## Typical Applications
• Industrial temperature monitoring and data logging
• Multi-point voltage acquisition and transducer interfacing
• Portable environmental and thermal testing
• Research instrumentation requiring flexible channel expansion
• Field diagnostics and system validation
## Compatibility & Integration
The module operates as a USB device requiring only driver software and standard hub infrastructure. Cascading up to 100 units through commercial USB hubs eliminates the need for specialized expansion chassis or external power distribution systems.
