PMM EHP-50B & EHP-50C Triaxial ELF Electromagnetic Field Probe

Overview

The PMM EHP-50B and EHP-50C are precision triaxial electromagnetic field (EMF) probes engineered for accurate, broadband assessment of extremely low frequency (ELF) electric and magnetic fields in occupational and environmental monitoring applications. Operating across a continuous frequency range from 5 Hz to 100 kHz, these probes comply with the fundamental measurement requirements defined in IEC 61786-1:2013 for electromagnetic field meters used in human exposure evaluation. Each probe integrates three orthogonal magnetic field sensors—induction coils—and three orthogonal electric field sensors—parallel-plate capacitors—physically aligned and co-located within a compact cubic housing (70 mm × 70 mm × 70 mm). This geometric configuration ensures vectorially complete field sampling without spatial averaging errors, enabling true root-mean-square (RMS) magnitude calculation and directional analysis per axis. The probe communicates exclusively via fiber-optic link to the PMM 8053A field analyzer, eliminating galvanic coupling and ensuring immunity to ground loops or RF interference during high-sensitivity measurements.

Key Features

• Triaxial simultaneous measurement of electric (E-field) and magnetic (H-field) components with full vector resolution
• Integrated digital signal processor (DSP) supporting real-time Fast Fourier Transform (FFT) spectral analysis with seven user-selectable resolution bandwidths (RBW)
• Built-in EEPROM storing factory calibration coefficients, frequency-dependent sensitivity tables, and traceable level calibration data
• Fiber-optic interface compliant with PMM 8053A analyzer—ensures electrical isolation, noise immunity, and extended cable reach (up to 100 m)
• Autonomous operation enabled by high-capacity rechargeable battery: up to 168 hours (7 days) in low-duty-cycle monitoring mode; typical runtime exceeds 12 hours under continuous acquisition at full bandwidth
• Onboard microcontroller managing sensor excitation, analog-to-digital conversion synchronization, battery charging regulation, and status LED signaling
• Compact, isotropic cubic design optimized for minimal field perturbation and repeatable positioning in compliance testing scenarios

Sample Compatibility & Compliance

The EHP-50B/C probes are validated for use in complex EMF environments including power substations, traction systems (railway electrification), industrial induction heating equipment, welding facilities, and medical MRI support infrastructure. Their dual-field capability supports simultaneous assessment against both ICNIRP 2010/2020 and IEEE C95.1 reference levels for public and occupational exposure. Measurement protocols align with EN 50499:2016 (assessment of EMF in workplaces) and EU Directive 2013/35/EU on electromagnetic fields. All calibration data is traceable to national metrology institutes (e.g., INRIM, Italy) and includes uncertainty budgets per ISO/IEC 17025:2017 requirements. The probe’s mechanical construction meets IP54 ingress protection for field-deployable robustness.

Software & Data Management

When paired with the PMM 8053A analyzer, the EHP-50B/C enables full spectral visualization, marker-assisted peak identification, and time-domain logging with timestamped metadata. Data export supports CSV and binary formats compatible with MATLAB, Python (NumPy/Pandas), and industry-standard EMF reporting tools. Firmware updates are performed via optical interface using PMM’s certified configuration utility. Audit trails—including operator ID, calibration date, measurement duration, and instrument serial numbers—are automatically embedded in exported datasets to support GLP/GMP-aligned documentation workflows. Optional software modules provide automated report generation compliant with national regulatory templates (e.g., German BGV B11, French ICNIRP implementation guidelines).

Applications

• Ongoing compliance verification of workplace EMF exposure near transformers, switchgear, and busbars
• Pre-commissioning surveys for renewable energy installations (e.g., solar inverters, wind turbine converters)
• Verification of shielding effectiveness in laboratories, control rooms, and medical imaging suites
• Research-grade characterization of harmonic content in distorted supply networks (e.g., VFD-driven motors, rectifier loads)
• Long-term ambient monitoring campaigns for epidemiological studies requiring traceable, low-drift instrumentation
• Calibration reference transfer between accredited labs and field service teams

FAQ

What distinguishes the EHP-50B from the EHP-50C?

The EHP-50B is optimized for magnetic field measurements only, while the EHP-50C supports simultaneous electric and magnetic field detection within the same physical probe.
Is fiber-optic connectivity mandatory?

Yes—the EHP-50B/C lacks any electrical output interface and requires the PMM 8053A or compatible fiber-linked host unit for operation and data retrieval.
Can the probe be used with third-party analyzers?

No—firmware, protocol stack, and optical encoding are proprietary to PMM systems; interoperability is limited to PMM-certified hardware.
How often does the probe require recalibration?

Annual recalibration is recommended per ISO/IEC 17025 and manufacturer guidelines; calibration certificates include full frequency-response verification from 5 Hz to 100 kHz.
Does the probe support time-weighted average (TWA) calculations?

Yes—when operated with the 8053A, it calculates TWA values in accordance with ICNIRP and EU Directive 2013/35/EU exposure limit algorithms.