Alphalab GM1-ST DC Gaussmeter

Overview

The Alphalab GM1-ST DC Gaussmeter is a precision single-axis magnetic field measurement instrument engineered for reliable, high-resolution quantification of static (DC) magnetic flux density in industrial, quality control, and R&D environments. Utilizing a calibrated Hall-effect sensor integrated into a compact, rigid yet bendable probe tip, the GM1-ST operates on the principle of transverse voltage generation across a semiconductor element under perpendicular magnetic flux—enabling direct, linear, and polarity-sensitive measurement of magnetic fields up to ±19,999.9 Gauss (±1.99999 Tesla). Its fixed-range 5½-digit display eliminates manual range switching, delivering stable, real-time readings updated four times per second without warm-up delay or user configuration. Designed for immediate deployment, the instrument requires no initial calibration or zeroing setup beyond its built-in auto-zero function—making it suitable for rapid spot checks, comparative magnet grading, and in-situ field mapping where repeatability and traceability are essential.

Key Features

• True 5½-digit resolution (±19,999.9 G) with polarity indication—no range selection required
• 0.1 G minimum resolution enables detection of subtle field drifts, aging effects, or inconsistencies across magnet batches
• Integrated Hall probe with 1.5 mm profile allows insertion into narrow air gaps (e.g., between pole pieces or within magnetic assemblies)
• 100 cm flexible cable permits probe repositioning; tip can be gently bent into an “L” shape for confined-space measurements (e.g., inside solenoids or electromagnetic coils)
• Auto-zero function subtracts ambient background field from subsequent readings; supplemented by fine offset adjustment (0.1 G steps, ±19,999.99 G range)
• NIST-traceable calibration certificate supplied with each unit, supporting ISO/IEC 17025-compliant laboratory documentation requirements
• CE-marked design compliant with IEC/EN 61326-1 for electromagnetic compatibility and electrical safety in industrial settings
• Low-power 9 V alkaline battery operation (~40 hours typical life) with visual low-battery indicator

Sample Compatibility & Compliance

The GM1-ST is optimized for measuring DC magnetic fields generated by permanent magnets (including NdFeB, SmCo, and ferrite types), electromagnets, magnetic separators, and magnetic holding fixtures. Its probe geometry accommodates surface-field verification on magnet faces, inter-pole gap characterization, and axial field profiling within cylindrical bores. The instrument meets the functional accuracy requirements for routine QC tasks referenced in ASTM A977/A977M (Standard Test Method for Magnetic Properties of High-Coercivity Permanent Magnet Materials) and supports GLP/GMP-aligned data integrity practices through its stable analog front-end and non-volatile display logic. While not FDA 21 CFR Part 11-enabled (as it lacks digital data logging), its NIST-traceable calibration and documented uncertainty budget support audit readiness in regulated manufacturing environments.

Software & Data Management

The GM1-ST operates as a standalone, hardware-only measurement system with no embedded memory or PC interface. All readings are displayed in real time on the integrated LCD and are not stored or exportable. This architecture ensures immunity to firmware corruption, software version conflicts, or cybersecurity vulnerabilities—critical for cleanroom, explosion-proof, or EMI-sensitive locations. For laboratories requiring digital recordkeeping, users may manually log values using validated electronic notebooks or integrate the GM1-ST into custom test stands via optional analog output modules (sold separately). Calibration records—including date, standard reference, and deviation values—are maintained independently per unit and archived alongside the physical NIST-traceable certificate.

Applications

• Verification of magnetic strength consistency across production lots of sintered or bonded permanent magnets
• Mapping stray fields near MRI shielding enclosures or magnetic separation systems to verify compliance with occupational exposure limits (e.g., ICNIRP guidelines)
• Characterizing residual magnetism in machined ferrous components post-demagnetization
• Validating field uniformity in magnetic chucks, lifting magnets, and magnetic conveyor systems
• Measuring field decay over time in aging magnet assemblies used in aerospace actuators or medical device motors
• Calibrating secondary field sensors or validating finite-element modeling outputs in magnetics design workflows

FAQ

Is the GM1-ST suitable for AC or pulsed magnetic field measurements?
No. The GM1-ST is strictly a DC gaussmeter. It does not respond to time-varying fields above ~1 Hz and is not rated for transient or alternating field applications.
Can the probe be replaced or recalibrated independently?
The Hall sensor is permanently integrated into the probe assembly and is not user-replaceable. Recalibration must be performed by an Alphalab-authorized service center using traceable standards; field recalibration is not supported.
What is the temperature coefficient of accuracy?
The specified ±1% accuracy applies only within 16–29°C ambient. Outside this range, accuracy degrades to ±2% (–4°C to +65°C), reflecting thermal drift of the Hall element and signal conditioning circuitry.
Does the instrument meet MIL-STD or automotive OEM specifications?
While not certified to specific MIL-STD-810 or OEM-specific magnetic test protocols (e.g., GMW3172), its performance envelope and NIST traceability enable compliance with internally defined acceptance criteria when validated per customer qualification procedures.
Is the rubber boot removable for cleaning or sterilization?
Yes—the soft-touch rubber overmold is mechanically clipped and fully detachable, allowing for alcohol wipe-down or ISO Class 5-compatible cleaning without damaging the underlying housing or display.