Campbell Scientific TM320 Temperature and Humidity Data Logger

Overview

The Campbell Scientific TM320 Temperature and Humidity Data Logger is a rugged, field-deployable environmental monitoring instrument engineered for long-term, unattended measurement of ambient temperature and relative humidity. Based on capacitive polymer humidity sensing and precision thermistor-based temperature detection, the TM320 operates on well-established physical principles—namely, dielectric constant variation in response to moisture absorption and resistance–temperature correlation in NTC thermistors. Designed for continuous operation in industrial, laboratory, pharmaceutical, cold-chain logistics, and HVAC validation environments, it delivers traceable, time-stamped measurements compliant with foundational environmental monitoring requirements under ISO 17025-accredited calibration practices and FDA-relevant data integrity expectations.

Key Features

• High-resolution dual-parameter logging: Simultaneous acquisition of temperature (−20 to 70 °C) and relative humidity (0–95 %RH, non-condensing), with stated accuracy of ±0.5 °C and ±2 %RH respectively.
• Configurable sampling interval: Programmable from 1 second to 24 hours in 10-second increments—enabling optimization for transient event capture or extended archival monitoring.
• Robust local data storage: Internal memory capacity of 32,000 timestamped records ensures uninterrupted logging over months—even during network outages or power interruptions.
• Flexible data retrieval: Integrated USB 2.0 interface enables direct PC connection for rapid configuration and download; optional SD card slot supports one-step bulk export without proprietary drivers.
• Real-time user feedback: Backlit LCD display shows current readings, min/max values, alarm status, battery level, and elapsed run time—no software required for basic verification.
• Dual power architecture: Operates on standard 4×AA alkaline cells (typical life >12 months at 15-minute intervals) or an external AC adapter for permanent installations.
• Industrial-grade enclosure: Polycarbonate housing rated IP54 for dust resistance and limited water exposure—suitable for controlled rooms, warehouses, cleanrooms (Class 8), and transport validation scenarios.

Sample Compatibility & Compliance

The TM320 is not a process sensor but a standalone environmental recorder intended for ambient air monitoring in static or low-velocity environments. It is unsuitable for direct immersion, high-velocity airflow (>2 m/s), or condensing conditions. Its performance specifications align with common reference standards for environmental monitoring instrumentation—including ASTM E2251 (Standard Specification for Temperature and Relative Humidity Sensors Used in Environmental Chambers), ISO 14644-3 (Cleanroom testing), and USP <1058> (Analytical Instrument Qualification). While the device itself carries CE marking for EMC and LVD compliance, users are responsible for establishing metrological traceability through periodic calibration against NIST-traceable references per ISO/IEC 17025 guidelines.

Software & Data Management

Data configuration and retrieval are supported via Campbell Scientific’s free LoggerNet-compatible utility (Windows only) or third-party CSV-compatible applications. The device generates timestamped .CSV files compatible with Excel, MATLAB, Python (pandas), and LIMS platforms. Audit trail functionality—including user-initiated start/stop commands, alarm log entries, and configuration changes—is preserved in metadata headers. Though the TM320 does not natively support 21 CFR Part 11 electronic signature or audit trail encryption, its raw data output can be integrated into validated systems that enforce ALCOA+ (Attributable, Legible, Contemporaneous, Original, Accurate) principles when deployed within GxP-regulated workflows under documented SOPs.

Applications

• Pharmaceutical stability chambers and warehouse environmental qualification (IQ/OQ/PQ)
• Cold chain validation for vaccine and biologics distribution (per WHO TRS 961 Annex 9)
• ISO Class 5–8 cleanroom environmental monitoring programs
• University and government lab ambient condition logging for equipment qualification
• Building automation system (BAS) commissioning and HVAC performance verification
• Archival climate monitoring in museums, libraries, and archival storage facilities
• Field-deployed environmental baselines for ecological or agricultural studies

FAQ

Is the TM320 suitable for use in saturated or condensing environments?
No. The sensor is rated for 0–95 %RH non-condensing operation only. Prolonged exposure to condensation may degrade the polymer humidity element and invalidate calibration.
Does the device support real-time remote data streaming?
No. The TM320 is a stand-alone logger with no built-in wireless or Ethernet connectivity. Remote access requires manual retrieval or integration with external gateways (e.g., Campbell’s CR1000X with cellular modem).

Can the internal clock be synchronized to NTP or GPS time sources?
No. Time is set manually via software prior to deployment and drift is typically <±2 seconds/month at 25 °C.

What is the recommended calibration interval?
Campbell Scientific recommends annual calibration under normal use; however, frequency should be risk-assessed per ISO/IEC 17025 Clause 7.7 and aligned with internal quality procedures, especially in regulated environments.

Is the SD card slot compatible with all SDHC formats?
Yes—tested with SDHC cards up to 32 GB. Cards must be formatted as FAT32 prior to first use.