CENTER 314 Digital Thermohygrometer

Overview

The CENTER 314 Digital Thermohygrometer is a dual-sensor, handheld environmental monitoring instrument engineered for precision measurement of ambient temperature (T1) and relative humidity (RH), with integrated support for external K-type thermocouple input (T2). Its measurement architecture employs calibrated capacitive polymer humidity sensing elements and high-stability NTC/RTD-based temperature transducers, ensuring repeatable performance across industrial, laboratory, and facility management applications. Designed for field-deployable reliability, the device complies with CE marking requirements for electromagnetic compatibility (EMC) and low-voltage directive (LVD) conformity—critical for use in EU-regulated environments including cleanrooms, HVAC validation, and warehouse environmental monitoring. The instrument operates on a single 9V alkaline battery and features an auto-power-off function to extend operational life between replacements.

Key Features

• Triple-parameter real-time display: simultaneous readout of T1 (ambient temperature), RH (relative humidity), and T2 (external K-type probe temperature) on a high-contrast 4-digit LCD screen
• High-capacity internal data logger storing up to 16,000 timestamped records, supporting post-acquisition trend analysis and compliance documentation
• RS-232 serial interface enabling direct connection to Windows-based PCs for continuous data streaming, automated logging, and integration into existing quality management systems (QMS)
• Dedicated Windows-compatible software package providing configurable sampling intervals, graphical plotting, export to CSV/Excel, and customizable report generation
• Extended-range K-type thermocouple input (−200°C to +1370°C) with linearized output and compensated cold-junction reference, suitable for furnace, sterilization, and thermal process verification
• Robust mechanical design: impact-resistant ABS housing, ergonomic grip, and included protective leather case for transport and storage
• Comprehensive measurement functions including MAX/MIN tracking, data hold, and automatic zero calibration for humidity sensor drift compensation

Sample Compatibility & Compliance

The CENTER 314 is intended for non-invasive, ambient air condition monitoring and surface or process temperature verification via optional K-type probes. It does not require sample preparation or consumables. Its humidity sensor is optimized for typical indoor and light-industrial atmospheres; prolonged exposure to condensing conditions, corrosive gases (e.g., H₂S, Cl₂), or particulate-laden airstreams may affect long-term stability and is therefore not recommended without appropriate filtration or protective sheathing. The instrument meets CE Directive 2014/30/EU (EMC) and 2014/35/EU (LVD), and its measurement performance aligns with general-purpose metrological expectations defined in ISO 17025-accredited laboratories for environmental parameter verification. While not certified to IEC 60584-1 (K-type thermocouple standard) or ISO 4677 (humidity sensor calibration), it delivers traceable performance suitable for routine QC checks, preventive maintenance logging, and GLP-aligned environmental recordkeeping.

Software & Data Management

The bundled Windows application provides full control over data acquisition parameters—including sampling rate (1 s to 3600 s), trigger conditions (threshold-based logging), and file naming conventions. All logged datasets include embedded timestamps synchronized to the host PC clock. Export functionality supports CSV, TXT, and Excel (.xlsx) formats, facilitating import into LIMS, ERP, or statistical process control (SPC) platforms. Audit trail capabilities are limited to local file metadata (creation/modification time); for FDA 21 CFR Part 11 compliance, users must implement supplementary electronic signature and access-control layers at the system level. The RS-232 protocol uses standard ASCII framing (9600 bps, 8N1), compatible with third-party SCADA and building management systems (BMS) when configured with appropriate serial-to-IP gateways.

Applications

• HVAC system commissioning and seasonal performance verification
• Pharmaceutical warehouse and cold-chain storage environmental qualification (IQ/OQ support)
• Electronics manufacturing cleanroom humidity surveillance
• Food processing ambient condition monitoring per HACCP prerequisite programs
• Thermal validation of ovens, autoclaves, and drying tunnels using K-type probe extension
• Educational laboratory experiments requiring multi-point environmental correlation
• Facility maintenance logs for predictive analysis of climate-related equipment degradation

FAQ

Is the CENTER 314 calibrated before shipment?

Yes, each unit undergoes factory calibration against NIST-traceable reference standards for both T1 and RH channels. A basic calibration certificate is included; full ISO/IEC 17025-certified calibration is available as an optional service.
Can the internal humidity sensor be recalibrated in the field?

No—capacitive RH sensors are not user-recalibratable. However, the instrument supports zero-point humidity adjustment using saturated salt solutions (e.g., NaCl at 75.3% RH @ 25°C) for periodic verification.
What is the maximum cable length supported for RS-232 communication?

For reliable operation without signal degradation, the RS-232 cable should not exceed 15 meters. Use shielded twisted-pair cabling and ensure proper grounding to minimize noise in electrically noisy environments.
Does the device support USB connectivity?

No—only RS-232 serial interface is provided. A USB-to-RS232 adapter (FTDI chipset recommended) is required for modern laptops lacking native COM ports.
How frequently should the K-type probe be verified for accuracy?

Industry best practice recommends verification at least once per shift in critical thermal processes, or prior to each use in GxP environments, using a calibrated dry-block or ice-point reference.