Weighing indicators & controllers

Depending on the place of use, a weighing indicator must meet very different demands: Beyond general protection against contact, a dusty environment requires at least IP protection class 5x, and an outdoor installation requires at least protection against splash water. In the food and pharmaceutical industries, housings must be made of stainless steel and be designed for cleaning with a steam jet. In the chemical industry, resistance to certain acids and bases is also required.

In an environment with powerful electric motors, transformers or switchgear, care must be taken to ensure high compatibility with electromagnetic interference. When used in hazardous area, the weighing terminal must have suitable approval according to the ATEX guidelines.

SysTec weighing indicators / terminals are characterized by robust stainless steel housings with protection class IP65 and IP69K. The fascia plate with integrated membrane keyboard is resistant to all common solvents and cleaning agents. Due to their design, the terminals are insensitive to electromagnetic interference up to field strengths of more than 50V/m. SysTec weighing indicators are available with ATEX approval for zones 2 and 22; IT3000EX and IT8000EX also with approval for zones 1 and 21.

The most important feature of a weighing indicator / terminal is, of course, the scale connection. Depending on the application, it must be possible to connect one or more scales to a weighing terminal. In addition to analog strain gauge load cells, digital load cells from various manufacturers or digital weighbridges and precision scales are increasingly coming into focus. The applications range from simple static weight recording to dynamic high-speed checkweighers.

SysTec weighing indicators - depending on the chosen model - can be equipped with one or two internal scale interfaces for the connection of analog load cells. Alternatively, weighing interfaces are available for the connection of digital load cells and scale bases from HBM, Flintec, Satorius/Minebea or others. For applications with multiple scales, such as tank farm or silo monitoring, the number of scale connections can be increased to over 30 via external multiplexers. Furthermore, the extremely high measuring rate of over 800/s makes SysTec indicators and controllers particularly suitable for dynamic weighing systems.

If the weight is read from the scale for the purpose of commercial transactions (trade) or for the determination of a fee, the scale is subject to W&M approval. This also applies in particular to scales used to determine the price by weight and for the production and inspection of prepackaged goods. The weight indicator used must be 'verifiable', i.e. have a type examination certificate corresponding to the application.

SysTec weighing indicators and controllers have an EC type examination certificate as non-automatic weighing instrument (NAWI) with a resolution of up to 10,000 increments, as well as EC type examination certificates for use as automatic catchweighing instrument, automatic gravimetric filling instrument (AGFI), automatic checkweighing instrument and for continuous / discontinuous totalizing.

In addition, SysTec weighing systems have approvals for use in legal metrology in many non-European countries, such as the USA, Canada, Australia, Russia and many more.

Depending on the type of application, it must be possible to connect various peripheral devices to the weighing indicator. In detail, these can be a protocol and/or label printer or a second weight display. Data transmission to the on-site EDP system is almost obligatory today, as is connection to an existing PLC via field bus. It is not only important that the weighing terminal has a sufficient number of physical interfaces, it must also support the correct procedures and/or fieldbus protocols.

Depending on the chosen unit, SysTec weighing electronics can be equipped with one to six interfaces. In addition to the classics such as RS232 and RS422/485, Ethernet TCP/IP and USB are also available. For the fieldbuses, the system integrator can choose between Profibus DP, Profinet, EtherNet IP and Modbus TCP. Of course, the classic digital and/or analog inputs/outputs are also available for simple applications.

Very often, weighing indicators are used in industrial applications not only for the simple capturing of weight, but they must also be able to carry out additional tasks. For example, in a filling installation, the filling valve is controlled directly by the scale, which automatically calculates the switch-off point and closes the valve precisely before the target quantity is reached. Tolerance check, subsequent top-up filling or rejection and, if necessary, logging on printer, EDP or in file are further tasks that must be performed by the weighing indicator in a filling system. When selecting a suitable weighing terminal, care must be taken to ensure that suitable application software is available for the weighing indicator and that it meets all relevant requirements.

A wide choice of very sophisticated application programs is available for the SysTec weighing indicators. These range from data capturing and piece counting to batching programs for the filling of containers of all types with liquids or solids, recipe scales, receiving/shipping scales, truck scales, belt weighers and high-speed checkweighers. All applications are highly configurable and can thus be adapted to almost any requirement encountered in practice. And should there ever be an application that cannot be covered by a standard program, the programs can be customized with manageable effort or even designed as an individual solution by a team of experienced software engineers according to customer specifications.

The best application program is not much good if it cannot be operated easily and intuitively. This requires clear structuring of the process, where all important functions are easily accessible, as well as clear status displays and prompts in the operator's language.

SysTec weighing electronics are equipped with a large color display and their developers had a clear focus on optimal operability. The input menus are in operator language and have a help function that can be called up via function key, which provides additional information on the respective parameters. All function keys are labeled according to their current function (soft keys). Any error message is displayed to the operator in plain text in the same way as the current process step of the program (e.g. 'Filling fast...'). Where it makes sense, the application program shows an additional graphic that visually supports the plain text message.

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