The experimenters all know that the rigor of the experiment and the standardization of the research require the experimenters to carefully maintain each experimental instrument.
The daily maintenance of electronic scales involves preheating and calibration before each use.
Why is calibration of electronic scales so important?
This article will start fromCharacteristics of the internal structure of the balanceLet me explain to youThe principle and necessity of balance calibrationAnd introduce it to youOHAUSThe AutoCal automatic calibration function and its advantages of electronic scales.

1

What is a weighing sensor and how does the weighing sensor in a balance work?

The electronic balance used in daily experiments is a precision instrument.
The weighing sensor is the core electromechanical device in electronic scales and is also a type of metal object.
When it is subjected to a load, it will deflect or bend. But this overall change is very small.
The following diagram is an example of a simple electromagnetic force compensation weighing sensor. The left image shows its unloaded state, and the right image shows its loaded state.
Through the diagram, we can see that applying a load causes the weighing sensor to bend or deflect.

Such deformation may be caused by the weight of the object or downward force, and the weighing sensor will convert such physical deformation that is difficult to observe with the naked eye into quantifiable electrical signals.

2
Can the thermal expansion and contraction of metals be ignored?

*Changes in temperature can cause thermal expansion and contraction of objects.

From a physics perspective, all objects we come into contact with every day, whether they are solids, liquids, or surrounding gases, are composed of tiny particles called atoms.
In solids, atoms are arranged in a specific way and are not allowed to move too much. However, when a substance is heated, energy is absorbed. This absorbed energy increases the kinetic energy of the atoms that make up it, which in turn causes the atoms to occupy more space, leading to the expansion of the object. On the contrary, when heat is removed, the kinetic energy stored in the atoms of a given material decreases, causing the material to contract.

This phenomenon is called thermal expansion and contraction.
Generally speaking, the expansion and contraction of materials such as metals can be almost negligible and will not have any consequences. However, in high-precision applications, even extremely subtle thermal expansion and contraction can pose challenges.
Electronic scales are very precise and sensitive. Even minor changes in the external environment can cause the weighing sensor to bend and deflect when not in operation.

3
Why is calibration necessary?

In order to obtain reliable results for each weighing on an electronic balance, we must reduce the impact of environmental changes. Balance calibration is such a necessary means.
Calibration refers to the application of known quality to check the measured values against reality(Known)Whether the values match.
calibration(Sometimes)Using external weights to complete, but there are several drawbacks to external calibration:

1. The operation is cumbersome and time-consuming;
2. External weights must be stored and handled properly - in some cases, contact with human skin can transfer a certain amount of oil onto the weights that exceeds the allowable tolerance range.

4
What is internal calibration?

The internal calibration or adjustment function that comes with the balance.
Internal calibration is a mechanism built into a balance, consisting of a motor and one or more weights of known mass installed inside the balance.
Users can initiate a process in which internal weights are automatically loaded onto the weighing sensor and the measured values are checked based on the expected values.
If these values are different, the balance will adjust itself to obtain the correct measurement value for the given load.
The internal calibration mechanism eliminates the need to purchase and maintain external weights, which is usually more effective than external adjustments.

AutoCal
OHAUS balance automatic calibration function

AutoCal is an automatic calibration mechanism embedded in the balance by OHAUS using its internal calibration function.Compared to regular internal calibration functions, it has a higher level of intelligence and automation.
An electronic balance with AutoCal function that can perform self-monitoring.
When the AutoCal mechanism detects temperature changes or reaches the set automatic calibration time interval, it will automatically trigger internal calibration.

AutoCal Automatic Calibration Live
The balance will automatically calibrate during non working hours

Function review
AutoCal automatic calibration mechanismThe balance can maintain weighing services in the current environment and can be used for daily use at any time.
No need for manual calibration and adjustment of the balance by the user, saving a lot of time for the experimenter and not affecting the smooth progress of the experiment.

Poke the video,
Entering the world of OHAUS electronic scales
Learn more about AutoCal's features!
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① Explorer series

② Adventurer AX Series

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