Magnetometers

Teslameters and gaussmeters for laboratories and production

SENIS makes handheld and benchtop instruments for measuring magnetic fields in laboratories, production lines and magnet systems. Choose a model for your field range, required accuracy, probe access and method of recording the results.

Most SENIS digital teslameters use an integrated three-axis Hall probe to measure Bx, By and Bz together and display the total field. The range also includes the 3NTA2 nanoteslameter with an AMR probe for very low DC magnetic fields.

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Which teslameter fits my measurement?

Start with how you will use the instrument:

• Live USB logging on a Windows PC: consider the 3MTS for three-axis display, recording and CSV/XLS export with the supplied software. For your own software, use the documented SENIS communication protocol delivered with the instrument.
• Portable magnet measurements without a PC: consider the battery-powered 3MH1-E for its device display and recording to SD card. Compare the required accuracy with the selected range; for tighter DC accuracy requirements, consider the 3MH4.
• Laboratory measurements: compare the required field range and allowable error with the 3MH4 and 3MH6-E specifications. A tighter accuracy specification is worth paying for when your measurement requires it. For very low DC fields (up to 0.5 mT), consider the 3NTA2.
• Integration into production equipment: compare the 3MH3 and 3MH4 connections and configured ranges. The display-free 3MH2 is a future option, subject to availability.

Compare performance · Check probes and access · Compare data connections

Find your contact and request a quotation. If you are unsure about the required accuracy or configuration, describe what you need to measure.

Compare field ranges and performance

The accuracy figures below are DC specifications. Frequency bandwidth does not establish AC measurement accuracy; ask SENIS for performance at your field amplitude and frequency.

1. 3MTS high-field ranges: on the ±3 T range, accuracy is 2% of range up to ±2 T and 3% up to ±3 T; the ±20 T value is 3–5%.
2. 3MH1-E: the ±4 T range is extrapolated from measurements up to ±2 T. Its accuracy may differ above 2 T. The four ranges above follow the current datasheet.
3. 3MH4 and 3MH6-E: the maximum 2.5 kHz bandwidth applies at 7,500 samples/s. The quoted DC accuracy applies at 10 samples/s. These are different operating settings. For the ±20 T range, factory calibration is performed up to ±2 T; the optional high-field calibration is performed up to ±9 T. Confirm accuracy for the selected high-field configuration.
4. 3MH3: up to 300 samples/s for 3-axis acquisition and up to 900 samples/s for 1-axis acquisition.

What resolution do I need?

Resolution describes the smallest field change the instrument can distinguish. Accuracy describes how closely the measured result agrees with the reference field. Choose both for the measurement you need to make. The figures below use different noise definitions and operating conditions; they are a guide to individual instruments, not a like-for-like ranking.

Full specifications are available through the linked product pages.

Calibration and recalibration

SENIS recommends an annual recalibration interval for the models in this guide. Typical recalibration time, subject to workload, is 4–6 weeks for the 3MH4 and 3MH6-E and 2–3 weeks for the 3MTS and 3MH1-E. Ask for the complete turnaround for your shipment and configuration.

For the 3MH6-E, probes calibrated up to ±2 T can be sent for recalibration without the electronics; probes calibrated for higher fields must be sent with the electronics. Contact SENIS or your regional distributor before sending equipment.

Calibration scope and certificates depend on the configuration. The standard 3MH4 and 3MH6-E configuration includes calibration for one selected range; additional calibrated ranges and an ISO/IEC 17025 certificate are quoted separately. For the 3MTS, specify the calibration coverage and certificate required; the 3MH1-E is factory-calibrated up to 2 T; and the 3NTA2 is calibrated up to 0.1 mT. For high-field configurations of the 3MH2, 3MH3, 3MH4 and 3MH6-E, discuss factory calibration up to ±2 T and the optional external calibration up to ±9 T. Specify the ranges and certificate required in the quotation.

Where can I buy?

If your location is covered by an official SENIS distributor, request your quotation and place your order through that distributor. For other countries and areas, contact SENIS Switzerland directly. Find your regional contact.

Tell us the magnetic field range, required accuracy, available probe space, cable length and how you want to record the data. This helps us specify the instrument, probe and calibration for your application. If you are unsure about the required accuracy or configuration, describe what you need to measure.

Find your contact and request a quotation

Frequently asked questions

Can one probe cover 0.5 mT to 0.5 T?

For the 3MTS, the same installed probe is used across the selectable ranges: changing from its ±100 mT range to its ±500 mT range does not require a second probe. Whether it meets your needs across 0.5 mT–0.5 T still depends on the required accuracy, especially at the low end. The 3MH1-E, 3MH4 and 3MH6-E also offer selectable ranges; specify the probe and calibration with the instrument.

For example, 1% of full scale on the 3MTS ±100 mT range is ±1 mT. That does not provide a precise measurement of a 0.5 mT field merely because the field falls inside the range. For low-field work, compare a smaller range and its specified accuracy and resolution. With the 3MH1-E ranges, a 0.5 T field requires its ±4 T range because it exceeds ±400 mT.

Can one instrument resolve 0.5 µT and measure up to 2 T?

The 3MH1-E can cover both tasks using different ranges. It has one probe with two integrated sensors. It specifies 0.5 µT standard deviation on the ±4 mT range at 10 samples/s with 1 s averaging; this is not absolute accuracy. No calibration certificate is issued for the ±4 mT range. A field of 2 T uses the ±4 T range, calibrated up to 2 T; above 2 T, calibration is extrapolated and accuracy may differ. The 0.5 µT figure does not apply on the ±4 T range. Confirm the required accuracy and configuration with SENIS.

Which probe fits the space available?

For narrow gaps, type H probes for the 3MH4, 3MH2 and 3MH3 are 0.75 mm thick and 2.0 mm wide, with lengths of 8, 47 or 71 mm. The type C probe used with the 3MH6-E and 3MH4 is 0.9 mm thick and 4.0 mm wide. The 3MTS probe including its holder is 1 mm thick; the 3MH1-E probe thickness is 1.6 mm.

The 3MTS comes in two versions: a fixed-holder probe or a probe on a cable. These are different instrument configurations, not interchangeable probes. The 3MH1-E has an interchangeable probe that can be used on an extension cable. The 3MH6-E uses interchangeable type C probes. For the 3MH4, specify the probe and its calibration together with the instrument.

Cable options depend on the model: 3MTS-2, 1, 2 or 5 m; 3MH1-E, an extension cable with length confirmed when ordering; 3MH4/3MH6-E/3MH2, lengths from 2 to 10 m; 3MH3, 2 to 20 m; and 3NTA2, up to 40 m. Discuss the geometry and required cable length when requesting a quotation.

Can I record data or connect my own software?

Choose the connection for the way you need to use the data. Recording a file for later export and acquiring measurements directly into your own system are different workflows.

With the documented SENIS communication protocol, delivered with the instrument, you can program your own acquisition in any language, for example C, C++, C#, Python, Delphi or LabVIEW. With your own software, the 3MTS can also be used on Linux; for other models and for network integration, ask SENIS to confirm the complete setup.

Teslameter or gaussmeter?

Both names refer to instruments for measuring magnetic flux density. Tesla and gauss are different units: 1 gauss equals 100 µT. The 3MTS, 3MH1-E, 3MH4 and 3MH6-E can display readings in both tesla and gauss.

How does a SENIS Hall probe work?

Integrated Hall elements measure magnetic field components in three directions. A temperature sensor supports compensation, and the electronics convert the signals into field readings. Probe geometry, calibration and the measurement conditions affect the result. The 3NTA2 uses an AMR probe rather than a Hall probe.