Precision Balances

To assist you in your precision balance purchasing decision, the PCE Instruments (PCE) technical sales and support team has put together the below criteria for selecting a precision balance. However, should you require additional assistance with finding the right precision balance for your application, please don't hesitate to contact PCE at or +44 (0) 2380 987 035 for PCE Instruments UK , or at or +1 (561) 320-9162 for PCE Americas Inc.

When evaluating different precision balances, ask yourself the following questions:

- What is the anticipated weight of the lightest sample?
This helps you determine the minimum capacity needed for your precision balance.

- What is the anticipated weight of the heaviest sample?
This helps you determine the maximum capacity needed for your precision balance. Please note that typically the higher the maximum load that a balance will accommodate, the less accurate the weighing capability of the balance will become. There are high-capacity high-resolution precision balances; however, the cost may be prohibitive.

- What are the anticipated dimensions of the sample?
This helps you determine the size of the platform or weighing pan needed for your precision balance. The platform or pan size should relate to the maximum load and measuring accuracy of the balance, as the platform or pan should be constructed to ensure the ideal placement of the sample in the center of the surface. If the load is placed outside the center of the pan, leverage can occur. While the load cells of most precision balances can compensate for the effects of leverage up to a certain angle, samples larger than the pan size must be positioned more carefully to ensure the center of gravity falls within the center of the pan. Traditionally, the more accurate a balance is, the smaller the platform or pan size is.

In some instances, a precision balance will feature an underfloor weighing function for weighing objects unable to be placed on the scale due to the object's size or shape. A precision balance with an underfloor weighing function will feature a hook on the bottom for suspending loads.

- What level of accuracy is required for your weighing purposes?
This helps you determine the resolution needed for your precision balance. If the measuring accuracy of the precision balance is not indicated separately, the basic formula to assess the accuracy of a precision balance is that the measurement deviation is the resolution value multiplied by 3 or 4. If better accuracy is desired, consider a buffer factor of 10 for the precision balance. For example: If a balance has a resolution 0.1 g, then a measurement uncertainty of approx. ± 0.3 g ... ± 0.4 g has to be assumed (unless otherwise described). However, if a measuring accuracy of 0.1 g is desired, then you should look for a precision balance with a resolution of 0.01 g (factor 10).

Depending on the application, a calibration weight set may come in handy for verifying the accuracy of the precision balance and, if necessary, to adjust the balance accordingly. Like any piece of weighing equipment, a precision balance can drift over time and increase the measuring error.

- What is the goal of weighing the sample?
This helps you determine if advanced functionality beyond weighing is needed for your precision balance. This question can only be answered by the balance's end user. Some examples of advanced functions include: sum, tare, recipe, piece counting, hold (animal weighing), density measuring, suspended weighing and drying (moisture content measuring). For some users, the piece counting function is essential for performing an inventory quickly. At the same time, other users need the piece counting function for checking product completeness. For the product completeness application, a light or indicator is required to confirm the desired result. While both kinds of users would like to use the piece counting function, each type of user has a different purpose. Not every precision balance with a piece counting function will include a light or indicator. That is why the purpose of weighing should be clearly defined by the end user and only then, according to the user's specific criteria, a precision balance should be selected.

- What do you plan to do with the weight data after the weighing process is complete?
This helps you determine if an interface is needed to connect your precision balanced to a PC or printer. An interface allows the weighing data to be transferred. Examples enabling data transfer include USB, RS-485 and RS-232 ports, Bluetooth and WLAN interfaces, analog outputs and removable memories (like SD cards or USB sticks).

- What documentation requirements must the precision balance meet for your organization's quality assurance program?
An optional ISO calibration certificate is available as an accessory to most PCE-branded precision scales for an additional fee. An ISO calibration certificate is a document with a PRESET / ACTUAL comparison of your device. An ISO calibration certificate documents the measurement deviation, linearity error, repeatability and measurement error of the excessive load.

- What is your price limit?
This helps you determine if a precision balance falls within your budget. After answering the above questions, you may have your purchasing decision narrowed down to a handful of different models of precision balances. It should be taken into account that the appropriate precision balance should simplify, expedite and/or make the weighing process safer or better. Therefore, it is not always worthwhile to choose the most affordable precision balance.