testo 174H Miniature Temperature and Humidity Data Logger

Overview

The testo 174H miniature temperature and humidity data logger is a compact, standalone environmental monitoring instrument engineered for long-term, unattended recording of ambient thermal and hygric conditions. Based on robust capacitive humidity sensing and precision NTC thermistor technology, the device operates according to standardized psychrometric principles and complies with fundamental metrological requirements for relative humidity and temperature measurement per IEC 60751 (for resistance thermometers) and ISO 4618 (humidity sensor stability classification). Its dual-channel architecture enables synchronous acquisition of both parameters at user-defined intervals—critical for validating storage environments, transport conditions, or controlled laboratory spaces where traceability and data integrity are mandated by GLP, GMP, or ISO/IEC 17025 frameworks.

Key Features

• Compact form factor (65 × 40 × 18 mm) with integrated wall-mount bracket for flexible installation in cabinets, cold rooms, shipping containers, or cleanroom pass-throughs.
• Non-volatile flash memory ensures full retention of up to 16,000 timestamped measurement records—even during complete battery discharge or power interruption.
• Real-time LCD display shows current temperature and relative humidity values, along with status indicators for alarm thresholds and logging activity.
• User-configurable logging interval from 1 minute to 24 hours via PC software—enabling optimization between resolution and memory longevity.
• High-stability capacitive RH sensor with long-term drift compensation; typical annual drift < ±0.5 %RH under standard indoor conditions (23 °C / 50 %RH).
• IP20-rated enclosure suitable for dry, non-dusty indoor environments; not intended for outdoor or high-condensation applications.

Sample Compatibility & Compliance

The testo 174H is designed exclusively for ambient air monitoring and does not support immersion, duct mounting, or aggressive chemical exposure. It meets CE marking requirements and conforms to RoHS Directive 2011/65/EU. While not certified to ATEX or IECEx standards, its low-power design and absence of intrinsic ignition sources make it appropriate for use in non-hazardous zones. For regulated industries—including pharmaceutical cold chain logistics, medical device storage, and archival climate control—the device supports audit-ready data export in CSV format, with timestamps traceable to UTC via host PC synchronization. Though not natively 21 CFR Part 11 compliant, raw data files can be archived within validated LIMS or ELN systems that implement electronic signature and audit trail functionality.

Software & Data Management

Data retrieval and configuration are performed using the proprietary testo Comsoft Basic software (Windows XP–Windows 7 compatible), which provides intuitive visualization tools including time-series plots, statistical summaries (min/max/avg), and configurable limit alarms. Export options include CSV and PDF report generation. All measurements are stamped with internal real-time clock (RTC) data; clock accuracy is ±2 seconds per day at 25 °C. The USB interface enables direct connection without external drivers—no additional hardware or dongles required. Firmware updates are distributed through testo’s official support portal and require manual initiation to preserve configuration integrity.

Applications

• Monitoring temperature and humidity excursions during pharmaceutical product storage (e.g., stability chambers, warehouse zones per ICH Q1A–Q5C guidelines).
• Verifying environmental compliance in museum artifact storage, library archives, and conservation labs per ISO 11799.
• Validating HVAC performance in office buildings, server rooms, and laboratories under ISO 14644-1 Class 8 cleanroom baseline conditions.
• Tracking shipment conditions for sensitive electronics, diagnostic reagents, or biologics across multi-leg logistics chains.
• Supporting internal quality audits where documented environmental history is required for ISO 9001:2015 Clause 7.1.5 or ISO 13485:2016 Clause 7.5.10.

FAQ

Does the testo 174H support external probes or analog inputs?
No. It features only built-in NTC and capacitive sensors; no expansion ports or probe interfaces are provided.
Can the device be calibrated in-house?
Field calibration is not supported. Users must send the unit to an accredited testo service center or third-party lab for traceable adjustment against NIST- or DAkkS-certified reference standards.
Is the battery replaceable by the end user?
Yes—the CR2450 coin cell is user-replaceable; however, battery replacement interrupts active logging and resets the internal clock unless synchronized immediately post-replacement.
What happens when memory reaches capacity?
The logger defaults to overwrite mode (FIFO), discarding oldest entries to accommodate new measurements—this behavior is fixed and non-configurable.
Is Bluetooth or wireless connectivity available?
No. Communication is limited to wired USB 2.0; no Wi-Fi, BLE, or cellular telemetry options exist for this model.