Check weighing scales are used to monitor the weight of the product and number of checked packaged products. Typically the product passes along the conveyor to the weighing station where the product is weighed. In the question is about a defined weight, the scale will now compare the weight directly to the set value and to the given tolerances. When the tolerances are exceeded, the scales provides a separate signal so that the product can be pushed sideways or sorted into different compartments.
Check weighing scales are type approved measuring instruments to directive MID 2014/32/EU and are usually verified with (weighing) inspected weights. If data transmission is used in an external system, the scales terminal is provided with a log memory that stores the registered weights complete with identification information (e.g. running number and time stamp). If weighing data is used for invoicing, in an external system, it is also necessary to ensure that this identification information is also transported as far as to the invoice, so that this backup chain is not broken. If necessary, weighing must be able to retraced from the customer's system and it checked from the log memory.