testo 175 T3 Dual-Channel External Thermocouple Data Logger (Type K/T)

Overview

The testo 175 T3 is a robust, dual-channel external thermocouple data logger engineered for long-term, unattended temperature monitoring in industrial, HVAC, pharmaceutical, and laboratory environments. It supports simultaneous high-precision measurement via two independent thermocouple inputs—compatible with standard Type K (NiCr–Ni) and Type T (Cu–CuNi) sensors—enabling differential or multi-point thermal profiling without hardware duplication. Its core architecture follows the principle of distributed sensing: the logger itself houses no integrated temperature sensor; instead, it functions as a calibrated, time-synchronized acquisition unit that digitizes analog thermoelectric voltage signals from externally connected probes, applying cold-junction compensation (CJC) and NIST-traceable linearization algorithms per IEC 60584-1. This design ensures metrological integrity across the full operational range (−50 °C to +1000 °C), contingent upon probe selection. With an IP65-rated enclosure, internal non-volatile memory retaining 1 million timestamped readings, and automatic data retention during battery replacement, the device meets fundamental requirements for GLP-compliant thermal validation and continuous process verification.

Key Features

• Dual isolated thermocouple inputs supporting simultaneous Type K and Type T probes—no cross-talk or shared reference junction interference
• Non-volatile flash memory preserving all stored data during power loss, battery replacement, or extended storage
• Backlit LCD display showing real-time channel values, user-defined alarm thresholds, min/max statistics, battery status, and over-limit indicators—no PC required for field verification
• Configurable logging interval from 10 seconds to 24 hours, enabling adaptive resolution for transient events or seasonal trend analysis
• Integrated wall-mount bracket with security lock slot for tamper-resistant fixed installations in mechanical rooms, cleanrooms, or utility corridors
• Three-year battery life (typical use: 15-minute interval at +25 °C) using standard AAA alkaline cells—field-replaceable without tools or calibration interruption

Sample Compatibility & Compliance

The testo 175 T3 does not perform measurements autonomously; its accuracy and range are determined entirely by the connected thermocouple probe. testo offers a validated portfolio of surface, immersion, air, and penetration probes—each with documented uncertainty budgets traceable to national standards. When paired with appropriate probes, the system supports applications requiring compliance with ASTM E2877 (for thermal mapping), ISO 14644-3 (cleanroom temperature uniformity), and USP (storage condition monitoring). The device’s firmware and optional ComSoft CFR 21 Part 11 software module provide audit trails, electronic signatures, and role-based access control—fulfilling FDA 21 CFR Part 11 Annex 11 and EU GMP Annex 11 requirements for regulated environments. All units ship with factory calibration documentation (DIN EN ISO/IEC 17025 accredited) and CE marking per applicable EU directives.

Software & Data Management

Data configuration and retrieval are managed via testo’s ComSoft software suite. ComSoft Basic (freely downloadable) enables instrument setup, threshold definition, and CSV export—including Excel-compatible templates with embedded metadata (date/time, channel ID, units, probe type). ComSoft Professional adds statistical process control (SPC) charts, deviation reporting, automated PDF report generation, and database integration (ODBC). For pharmaceutical and biotech users, ComSoft CFR 21 Part 11 implements full ALCOA+ principles: attributable, legible, contemporaneous, original, accurate, complete, consistent, enduring, and available records—with electronic signature enforcement, change history logging, and 21 CFR Part 11-compliant user management. Data transfer occurs via USB 2.0 interface (cable optional) or removable SD card (optional), both supporting encrypted file transfer and write-protection modes.

Applications

• Heating, ventilation, and air conditioning (HVAC): simultaneous supply/return air or inlet/outlet pipe surface temperature logging for energy efficiency audits and ASHRAE-compliant commissioning
• Pharmaceutical cold chain validation: dual-point monitoring of refrigerator/freezer interiors or transport container thermal gradients per WHO TRS 961 and EU GDP guidelines
• Industrial process control: furnace chamber profiling, reactor jacket temperature differentials, and sterilization cycle verification (e.g., autoclave load mapping)
• Food safety HACCP monitoring: time-temperature profiling of cooking, chilling, and holding stages per FDA Food Code §3-501.14
• Building envelope diagnostics: comparative surface temperature analysis across insulation interfaces or thermal bridges under steady-state conditions

FAQ

Does the testo 175 T3 include built-in temperature sensors?
No—the device contains only thermocouple input circuitry and requires at least one external Type K or Type T probe to operate.
Can I use third-party thermocouples with this logger?
Yes, provided they conform to IEC 60584-1 specifications for Type K or Type T; however, accuracy and calibration validity depend on probe quality and traceability.
Is the memory capacity shared between both channels?
Yes—1,000,000 readings represent total storage across both channels; logging interval and active channels determine effective duration.
What happens if the battery dies mid-recording?
All logged data remains intact in non-volatile memory; the device retains time/date continuity upon battery replacement.
Is USB cable included in the standard package?
No—USB cable and SD card are optional accessories; the base package includes wall mount, lock, batteries, and calibration certificate.