Internal calibration vs external calibration

If you are looking for highly accurate lab balances, you may have noticed that some balances offer optional internal calibration. If you need to use precise weighing instruments for complex applications, you understand the need for calibration. But if you have to choose between two sizing options, how do you choose? What are the differences? What are the positives and negatives? 

All balances should be calibrated, but the higher the resolution of the weighing instrument (such as analytical or semi-micro balances ), the more important the calibration is. We’ll explain the differences in calibration types to help you choose the best option for your applications.

Calibration can be defined as the act of verifying the readings of an instrument against a known standard (in the case of balances, a known mass) that reflects the metrological standard. Calibration essentially validates the results given by the instrument. The results can be considered accurate and reliable, helping to reduce measurement errors and uncertainties.

External calibration

External calibration is the process of calibrating a balance manually with predetermined masses. Users place the weighing instrument in calibration mode (manually or through the menus of a digital scale), place the calibration masses on the scale, and verify that the displayed weight is correct. For examples of external calibration, you can watch our external scale calibration tutorials on our youtube channel, or you can read the product manual.

To perform the external สอบเทียบเครื่องมือวัด calibration, you need calibration masses suitable for your balance (a semi-micro balance needs much smaller increments than a large pan precision balance). Calibration sets include several calibration poods, a box to store them, and gloves or tweezers to handle them. Calibration masses should be treated with extreme caution; they need to be cared for properly to stay the same weight. External calibration depends on two factors: the condition of the calibration masses and the correct calibration of the instrument.

This is a manual process, so be sure to incorporate the time needed to perform a correct external calibration into your routine when using a weighing instrument. Most scales can be calibrated externally. Some balances leave the choice to the user and include internal and external calibration. Some instruments and organizations require external calibration to be performed in service by authorized companies.

Internal calibration

Internal calibration is a process that uses the balance’s internal mechanism to calibrate itself. This is typically done with menus using the scale’s display and keyboard. This option adds to the cost of the scale, but users do not need to purchase a calibration set to calibrate the scale.

Some balances with internal calibration include automatic internal calibration. This drives up the price of the balance and is typically offered only for laboratory balances (precision, analytical, and semi-micro, for example). Users can set the scale to automatically calibrate at predetermined time intervals, if there are changes in the environment where the scale is used if there is a power outage, etc. 

This feature can be very handy in busy labs; users do not have to go through the calibration process and nobody will forget, so the balance gives reliable results and users can concentrate on sample preparation or other tasks.

So which option should i choose?

It depends. If you have the time to perform calibration routinely and a limited budget, balances with external calibration are the best options. If you don’t want to buy and maintain a set of masses or spend valuable hours calibrating your balance, in-house calibration saves you time. 

If you know the scale will be exposed to many small changes in the environment that could affect the scale’s accuracy, the automatic internal calibrator can save you time and money in the long run. Consider how much time you’ll spend calibrating the scale and whether that time would be better spent on other tasks.

Is internal or external calibration better?

External adjustment requires adequate adjustment and proper maintenance of both weight and weight. It’s fast and easy, but it takes effort to maintain perfect calibration. Internal calibration is most appropriate if the situation is different, or if the circumstances prevent the stability of the hand to adjust.

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