Campbell Scientific CR6 Data Acquisition System
| Brand | Campbell Scientific |
|---|---|
| Origin | USA |
| Model | CR6 |
| Processor | 32-bit ARM Cortex-M4 with hardware floating-point unit (100 MHz) |
| Internal Memory | 4 MB RAM, 6 MB flash for OS, 1 MB serial flash for program execution |
| MicroSD Card Support | Up to 16 GB |
| Real-Time Clock Accuracy | ±3 minutes/year (±10 µs with GPS synchronization) |
| USB Interface | USB 2.0 Full-Speed (12 Mbps), host/device capable |
| Ethernet | 10/100BASE-T |
| Communication Protocols | PakBus, SDI-12, SDM, RS-232, RS-485, CPI (Campbell Peripheral Interface) |
| U-Port Capabilities | Simultaneous analog/digital input, static vibration measurement (100 Hz – 6.5 kHz), bridge excitation (±2.5 V or ±2.5 mA), thermistor support (5 kΩ reference), frequency measurement up to 200 kHz |
| Analog Input | 12 single-ended or 6 differential channels |
| ranges | ±5000 mV, ±1000 mV, ±200 mV |
| Analog Output | 12-bit DAC (±2.5 V or ±2.5 mA) |
| Digital I/O | 12 configurable ports (3.3 V / 5 V logic) |
| Power Input | 12 V DC battery, solar (16–32 V DC), or USB |
| SW12V outputs | 2 × 12 V @ 1100 mA (20 °C) |
| Overvoltage Protection | All terminal strips include transient voltage suppression |
| Operating Temperature | −25 °C to +50 °C (extended range options available) |
| Dimensions | 20.3 × 10.2 × 6.1 cm |
| Weight | 0.42 kg |
| Compliance | CE, FCC Part 15 Class B, RoHS |
Overview
The Campbell Scientific CR6 Data Acquisition System is a high-performance, low-power environmental and industrial monitoring platform engineered for precision, reliability, and long-term unattended operation. Built around a 32-bit ARM Cortex-M4 processor with hardware floating-point acceleration, the CR6 executes complex data logging routines at 100 MHz while maintaining sub-microsecond timing resolution—critical for synchronized multi-sensor deployments. Its measurement architecture integrates advanced signal conditioning, galvanically isolated analog inputs, and proprietary U-port technology—the first in Campbell’s lineup to natively support static vibration analysis via high-fidelity frequency-domain sampling (100 Hz to 6.5 kHz). Unlike legacy dataloggers, the CR6 implements true simultaneous sampling across differential analog channels with 24-bit resolution, delivering effective noise floors as low as 50 nV (±200 mV range, differential, reversed measurement). Designed for harsh outdoor environments, it operates continuously from −25 °C to +50 °C and features comprehensive overvoltage protection on all terminal strips—ensuring survivability against lightning-induced transients and ESD events common in remote field installations.
Key Features
- U-port architecture enabling concurrent analog, digital, and static vibration measurements—including CSI-exclusive vibration spectral analysis without external signal conditioning
- Dual 12 V switched power outputs (1100 mA each at 20 °C) for powering sensors, telemetry radios, or peripheral actuators
- Integrated 10/100BASE-T Ethernet with native PakBus routing, supporting peer-to-peer networked datalogger arrays and remote firmware updates
- Full-featured USB 2.0 interface (12 Mbps) for direct PC connection, configuration, and high-speed data retrieval—no driver installation required on modern Windows/macOS/Linux systems
- CPI (Campbell Peripheral Interface) expansion port for daisy-chained CDM-series distributed modules, extending channel count without compromising timing integrity
- MicroSD card slot supporting up to 16 GB of removable non-volatile storage with wear-leveling and automatic file rotation
- Native support for SDI-12, SDM, RS-232, and RS-485 protocols—enabling seamless integration with third-party meteorological, hydrological, and geotechnical sensors
- CRBasic programming environment compatibility, including backward compatibility with CR1000/CR3000 OS syntax and full PakBus networking stack
Sample Compatibility & Compliance
The CR6 interfaces with a broad spectrum of scientific and industrial sensors—including thermistors, strain gauges, load cells, accelerometers, anemometers, rain gauges, water level transducers, and gas analyzers—via its programmable U-port and configurable digital I/O banks. Its analog input circuitry meets ASTM E74-21 requirements for force calibration system accuracy when used with certified load cells, and its real-time clock synchronization capability (≤10 µs drift with GPS discipline) satisfies ISO/IEC 17025 traceability prerequisites for time-stamped environmental monitoring. The device complies with FCC Part 15 Subpart B (Class B), CE Directive 2014/30/EU (EMC), and RoHS 2011/65/EU. While not inherently 21 CFR Part 11 compliant, audit-ready data integrity is achievable through CRBasic’s embedded event logging, checksummed data files, and optional secure remote access configurations aligned with GLP/GMP documentation workflows.
Software & Data Management
Data acquisition and system configuration are managed through Campbell Scientific’s industry-standard software suite: LoggerNet (for centralized network management), PC400 (for local setup), and the CRBasic Editor (for deterministic, deterministic-cycle programming). All CR6-generated data files are stored in binary format with embedded metadata—including sensor calibration coefficients, timestamped configuration changes, and hardware revision identifiers—ensuring full reproducibility. Optional LoggerNet Server enables automated FTP/SFTP upload, email alerts on threshold breaches, and integration with SCADA platforms via Modbus TCP or RESTful API adapters. Raw data exports support CSV, TOB1, and NetCDF formats, facilitating ingestion into MATLAB, Python (via pycampbellcr1000), or statistical process control (SPC) packages. Firmware updates retain user programs and calibration tables, minimizing field downtime during maintenance cycles.
Applications
- Long-term ecological research: eddy covariance flux towers, soil moisture–temperature profiling networks, and phenocam synchronization
- Civil infrastructure monitoring: bridge deck vibration spectra, tunnel convergence tracking, and dam seepage pressure arrays
- Renewable energy asset management: wind turbine yaw alignment validation, solar panel soiling rate quantification, and battery bank state-of-charge trending
- Regulatory compliance monitoring: EPA Method 9 opacity observers, ambient air quality (PM2.5, NOx) station telemetry, and wastewater treatment plant effluent parameter logging
- Geotechnical instrumentation: inclinometer string readouts, piezometer networks, and seismic array trigger coordination
- Industrial process control: HVAC system performance benchmarking, compressed air leak detection via acoustic emission, and predictive maintenance sensor fusion
FAQ
Does the CR6 support IEEE 1588 Precision Time Protocol (PTP)?
No—the CR6 relies on GPS-disciplined oscillator (GPSDO) synchronization for sub-10 µs time accuracy. PTP is not implemented, but PakBus time-synchronization commands enable microsecond-level coordination across CR6-based sensor clusters.
Can the CR6 execute custom signal processing algorithms in real time?
Yes—CRBasic supports user-defined functions, Fast Fourier Transform (FFT) libraries, and conditional logic loops. Complex spectral analysis (e.g., RMS vibration magnitude, dominant frequency extraction) can be computed onboard and logged at user-defined intervals.
Is the microSD card hot-swappable?
No—microSD insertion/removal requires a controlled shutdown sequence via CRBasic CardRemove() and CardInsert() instructions to prevent filesystem corruption.
What is the maximum cable length for RS-485 communication?
Up to 1,200 meters at 100 kbps using twisted-pair shielded cable (AWG 24), per TIA/EIA-485-A specifications. Termination resistors (120 Ω) are required at both ends of the bus.
How does the CR6 handle power failure recovery?
Upon power restoration, the CR6 resumes logging from its last known cycle with no data loss. Internal supercapacitors maintain RTC and RAM contents for ≥10 seconds, allowing graceful shutdown and preservation of unsaved buffer data.
