Field devices in the form of sensors, actuators and controllers form the basis of every industrial production process. However, automation is only possible through their networking and communication via protocols such as PROFIBUS. Reliable and seamless communication between the field devices and other components is therefore essential for the smooth and economical operation of devices and systems.
For data exchange via PROFIBUS, the networked field devices require a communication interface via which they send or receive commands or communicate and receive process data. This can be integrated into the automation devices in the form of a communication controller. There are various options for this:
ASICs specializing in communication, such as the netX SoCs from Hilscher, which can be used for other protocols in addition to PROFIBUS, are suitable for highly integrated solutions. These can already be taken into account in the basic design of a field device. For manufacturers, this solution offers maximum customization capability.
As the next stage of development, the communication interface can also be integrated into field devices as an embedded module. In addition to the ASIC, which is already located on the PCB, these have other electronic components such as connectors. Embedded modules mean less development and integration work for the device manufacturer.
It is also possible to integrate a ready-to-use communication interface for PROFIBUS with PC cards that already have all the peripheral components. Classic application examples for this can be found in industrial PCs for system or machine control, in HMI (Human Machine Interface) panels for machine monitoring, or in more application-specific solutions. Hilscher's cifX cards, for example, are available in a wide variety of form factors - from the smallest PC cards on the automation market in M.2 format for compact devices to classic formats such as for 19-inch systems.
The choice of communication interface
The various options for integrating PROFIBUS interfaces into sensors, actuators or controllers differ mainly in terms of the development effort required, which in turn has a major influence on the price and time-to-market. It is therefore important for device manufacturers to weigh up the options and take various factors into consideration, such as
New development or existing device: The easiest way to retrofit existing devices is via ready-to-use components such as PC cards. Thanks to the many different form factors, there is a suitable solution for every application, from compact robot arms to IPCs. For the new development of field devices, an ASIC or embedded module is usually the better option in order to integrate the communication interface as deeply as possible into the device and, for example, to cover additional tasks via the additional netX-internal application processor.
Unit quantities: The significantly higher development costs for embedded modules and chips for the design-in are generally not worthwhile for low quantities. The rule is: the higher the number of units, the higher the development costs can be.
Available space: The smaller the available space, for example with small sensors, the more difficult it is to integrate the communication interface as a prefabricated component. In addition to the space requirement itself, factors such as the heat development of the component, which can overheat more quickly in confined environments, also play a role here. With classic HMI terminals or industrial PCs, these factors tend to play a subordinate role.
Environmental influences: Field devices are often located in harsh environments and can therefore be exposed to dust, moisture, vibrations or even heat, among other things. Despite these influences, the continuous availability of industrial communication must be ensured in order to avoid machine or system failures. When selecting the communication interface, attention should therefore also be paid to appropriate robustness.
