Never zero your probe again
Offset errors in typical Hall probes occur for several reasons:
- Thermoelectric effects, which cause the offset to change with temperature.
- Imperfect contact placement geometry on the sensor, which creates so-called “misalignment voltage” errors that are harder to correct for.
These errors result in probe “drift,” impacting measurement repeatability.
Typical Hall probes must be regularly placed in a zero-gauss chamber to zero out offsets that develop over time.
TruZero™ technology
Lake Shore’s TruZero™ technology eliminates the need to perform these frequent zeroing operations, saving time and ensuring that measurements are always accurate.
This multi-part technology is accomplished through multiple mechanisms:
| 2Dex™ Hall effect sensors used in FP Series probes are highly symmetrical and uniform, resulting in inherently low zero-field offset voltages | |
| Special insulation used in the cable for optimum dielectric performance. | |
| An advanced sensor excitation “spinning” technique progressively switches between different measurement configurations. | |
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| An onboard algorithm combines the sequential Hall voltage readings in a way that eliminates any offsets due to misalignment and thermoelectric effects. This method also reduces flicker noise, meaning that readings are both more accurate and more precise. | |
This means there is never a need to “zero” the probe before making a measurement. TruZero™ technology allows fast, worry-free, and always accurate measurements.
TruZero™ demonstration
An experiment was conducted to observe the qualitative benefit delivered by TruZero technology.
- Model 475 and F71 placed in a temperature controlled room.
- Probes placed in zero gauss chambers where magnetic field is practically zero.
- 475 zeroed at the beginning of the experiment.
- Temperature cycled over multiple hours.
Outcomes
F71
- Very slight zero-offset drift with temperature
- No apparent drift with time
- Measurement resolution measured in nT
475
- More significant zero-offset drift with temperature
- Noticeable drift over several hours
- Measurement resolution measured in µT
Note: periodic recalibration of probe and teslameter is still required to maintain an accurate conversion from Hall voltage to a field value. Not all errors can be removed completely with TruZero. Very small residual errors, much smaller than Earth field, may remain.
