PMM HP-050 Triaxial Magnetic Field Probe

Overview

The PMM HP-050 is a high-stability, triaxial isotropic magnetic field probe engineered for precision low-frequency electromagnetic field characterization in laboratory, industrial, and regulatory compliance environments. It operates on the principle of three orthogonal induction coil sensors, each independently optimized for sensitivity and phase linearity across its specified bandwidth. Unlike Hall-effect or fluxgate-based alternatives, the HP-050 employs passive air-core coils with low thermal drift and minimal hysteresis—ensuring traceable, repeatable measurements from 10 Hz to 5 kHz. Its design targets applications requiring quantitative assessment of magnetic emissions from power electronics, transformers, medical devices (IEC 60601-2-25), and low-frequency infrastructure (e.g., railway traction systems per EN 50500). The probe’s passive sensing architecture eliminates self-noise contributions from active electronics, supporting high signal-to-noise ratio (SNR) measurements down to 10 nT without external amplification.

Key Features

• Triaxial isotropic response with <±0.3 dB deviation at 50 Hz under 200 nT excitation, verified per IEC 62110 Annex B calibration methodology
• Passive induction coil sensors with integrated low-noise preamplifier stage housed within the probe body—no external bias or warm-up required
• Built-in EEPROM calibration memory storing full frequency-dependent sensitivity coefficients, enabling plug-and-play traceability without manual coefficient entry
• Electric field rejection >20 dB achieved via symmetrical winding geometry and differential signal conditioning—critical for mixed E/H-field environments
• Thermal stability characterized at 0.015 dB/°C, allowing reliable operation across ambient temperatures from 5 °C to 40 °C without recalibration
• Rugged anodized aluminum housing (350 mm length, 133 mm diameter) with IP54-rated ingress protection for field-deployable robustness

Sample Compatibility & Compliance

The HP-050 is compatible with all standard spectrum analyzers, data acquisition systems, and PMM’s proprietary EHP-50 series measurement platforms via 50 Ω BNC output. It requires no external power supply—its integrated preamplifier draws minimal current from the connected instrument’s bias-T or dedicated low-noise power module. The probe meets essential requirements for electromagnetic compatibility (EMC) testing per CISPR 16-1-4 and supports conformity assessments aligned with IEC 61000-4-8 (power frequency magnetic field immunity testing) and IEEE Std 644–2021 (standard procedures for measurement of power frequency electric and magnetic fields). Calibration certificates are issued with NIST-traceable uncertainty budgets and comply with ISO/IEC 17025:2017 requirements when performed by accredited laboratories.

Software & Data Management

When used with PMM’s EHP-50 Control Software (v4.2+), the HP-050 enables real-time vector magnitude computation, spectral density mapping (nT²/Hz), and time-domain logging with timestamped metadata. All calibration parameters—including axis-specific amplitude and phase corrections—are automatically loaded from the onboard EEPROM. Export formats include CSV (with header-annotated units and traceability IDs), MATLAB .mat, and XML-compliant EMF reporting templates compliant with national environmental monitoring frameworks (e.g., Germany’s 26. BImSchV Annex 4). Audit trails record operator ID, calibration date, and instrument firmware version—supporting GLP and FDA 21 CFR Part 11 compliance when deployed in regulated quality assurance workflows.

Applications

• Low-frequency magnetic field mapping around HV substations and underground power cables per ICNIRP 2010 reference levels
• Pre-compliance EMC testing of industrial drives, UPS systems, and welding equipment per EN 61000-3-2 and EN 61000-3-12
• Biological exposure assessment in occupational settings (e.g., MRI facility perimeter surveys, maglev maintenance zones)
• Validation of magnetic shielding effectiveness in research laboratories and semiconductor cleanrooms
• Long-term environmental monitoring of geomagnetically induced currents (GICs) in energy grid infrastructure

FAQ

Does the HP-050 require periodic recalibration?
Yes—PMM recommends annual recalibration against a primary standard coil system in an accredited laboratory to maintain traceability to SI units.
Can the probe be used in pulsed magnetic fields?
It is suitable for repetitive transient fields with rise times ≥100 µs; for sub-microsecond pulses, consult PMM Application Note AN-HP050-03 for deconvolution guidance.
Is the probe compatible with third-party DAQ systems?
Yes—any system supporting 50 Ω input impedance, DC-coupled analog input, and voltage sensitivity ≥100 µV/nT can interface directly; PMM provides detailed pinout and scaling documentation.
What is the maximum continuous field exposure limit?
The probe is rated for continuous exposure up to 50 µT RMS; sustained operation above this level may induce minor coil heating and temporary sensitivity drift.
How is isotropy verified during calibration?
Using a three-axis Helmholtz coil system per IEC 62110, with angular rotation at 15° increments over full spherical coverage and vector error analysis per ISO/IEC 17025 clause 6.4.3.