Discover the secret that Fieldbus module manufacturers don’t want you to know
It’s a common misconception that to make your industrial equipment (Sensors, PLCs etc.) Fieldbus compatible, you need a dedicated hardware module to allow your embedded microcontroller to talk to whichever bus network (Profinet, EtherCAT, Modbus etc.) your equipment is intended to use. While this is a tried and trusted approach, it has many disadvantages, some of which are not so obvious. In this blog, we take a closer look at these before proposing an easier, cheaper, and much more flexible way that allows your industrial equipment to speak the language of whichever Fieldbus you want, simply by changing a few lines of code.
For your device to communicate with another with a piece of equipment across a Fieldbus network, it must be able to ‘speak the language’ of that Fieldbus, and an array of dedicated application-specific integrated circuits (ASIC) or hardware modules are available for this purpose. While this approach is low-risk and relatively easy to implement, it creates its own problems. This most obvious restriction is that it ties your device to a specific Fieldbus network. For example, if you design a Profinet module into your device, it can then only ever communicate with other Profinet devices. This immediately limits the market for your device only to customers with processes using Profinet. For your device to operate on other Fieldbus networks (e.g., Modbus), you need to do a costly and time-consuming board redesign using a different ASIC or hardware module. Furthermore, the functionality of your device is limited by the number of features available in the Profinet hardware module that you choose. Since access to an embedded software stack is usually very difficult (sometimes the manufacturers do not allow it to be modified at all), adding new features can be impossible. It also puts you at the mercy of your supplier, who can dictate the terms and conditions of how you use their module. For example, some insist on a royalty payment for every piece of equipment you produce which uses their module, and this can be a costly overhead to be factored in when setting the price of your equipment. It also makes you vulnerable to interruptions in their supply chain – if they cannot meet your orders, production may have to stop.
Software-enabled Fieldbus
Hardware module manufacturers are understandably delighted with themselves, having created such a stranglehold on the Fieldbus market, so they won’t want you to be aware of another way to make your device Fieldbus compatible – software! This approach involves simply sourcing and downloading a Fieldbus software stack onto your device microcontroller that allows it to talk directly to your chosen network and which bypasses the need for you to purchase an expensive hardware module. Even better, by tweaking the code in the stack, your device can communicate with any Fieldbus you wish. This completely opens your market because your device can be made to work on the bus networks used in virtually every industrial process, with no hardware redesigns to slow you down. It also removes supply-chain risks because you only need to purchase the software stack once, and by having full access to the code, you have the freedom to add multiple different features to your device.
If you’re interested in implementing Fieldbus using software, you should know that RT-Labs have a considerable amount of experience in industrial communications and have been supporting companies in implementing a Fieldbus software stack in their industrial equipment for many years. They have the in-depth knowledge required to make virtually any implementation possible, and can even help you with any hardware modifications you are thinking of making to your board.