Clarify what Codesys is, starting with the company 3S-Smart Software Solutions, PLCopen and SoftMotion in order to understand what each manufacturer offers in terms of Motion Control. And seeing that just because a product is based on Codesys and PLCopen Motion doesn’t mean they’re the same.
Who’s who and what’s what?
Starting from the beginning, in 1994 the company 3-S Smart Software Solutions GmbH was founded, which created the Codesys system (Controllers Development System) which is a hardware-independent development tool and compliant with the IEC 61131-3 standard. In 2020 the product name became the company name and 3-S Smart Software Solutions became Codesys GmbH.
On the other hand, the independent organization PLCopen was founded in 1992, shortly after the IEC 61131-3 programming standard was published. That arose because at that time there were as many types of programming as there were PLC manufacturers. Thanks to the standard, programming languages for PLCs, PACs, embedded controllers and industrial PCs are defined based on well-known methods such as text-based programming languages such as IL (Instruction List) and ST (Structured Text), or on graphic languages, such as the LD (Ladder Diagram), CFF (Continuous Function Chart), FB (Function Block) and SFC (Sequential Function Chart / Grafcet).
PLCopen Motion Control is a standard developed by the PLCopen organization, which provides libraries with standardized and reusable FBs for multiple hardware platforms in the field of motion control.
And finally SoftMotion, which is a CODESYS product, consists of a set of libraries that implement and adhere to PLCopen Motion standards, providing a standardized interface and functionality for motion control on software-based control platforms with Codesys, such as any IPC (Industrial PC) with a real-time operating system and a synchronous fieldbus, such as EtherCAT, SERCOS III, EtherNet/IP (CIP Synch), Profinet IRT, and PowerLink, to connect to servo drives and other I/O devices.
There are also manufacturers that have maintained their own systems, complying with IEC 61131-3. But without relying on PLCopen Motion.
So, are all the Codesys solutions used the same?
No, no two are identical, but they are all very similar. They all start from the same base, but each manufacturer opts for one or another tool, which it develops, to facilitate the work of the programmer. As an example, to facilitate the commissioning and maintenance of axles, TwinCAT has a tool that facilitates operation.
From the screen shown in the figure, we can handle an axis without writing a single line of code, see its statuses and values of speed, position, etc. Which comes in handy. Another manufacturer will have one or the other wizards for the configuration of the axes.
In the case of EcoStruxure Machine Expert, screens are available for the configuration and testing of a Delta robot or other devices, such as the one in the following image, where the object can be visualized in 3D while it can be moved manually, or to configure a SCARA robot, it will be enough to choose the product reference and all its parameters will be set automatically.
Or the wizard to configure the intelligent transport system (Multi Carrier) that will be different in each case but will perform the same function.
In the MLC system, a Face Plate is offered that displays the most representative of the axle.
Each manufacturer customizes their Codesys to their hardware and conveniences, etc.
You can also see differences in irrelevant topics such as the icons for servo drives or servo motors, in the following images you can see the differences between the representation of the icons of two manufacturers, each with its Codesys.
In this case, the icons used by the Schneider Electric Software (Left Figure) and the Bosch Rexroth Software (Left Figure) are shown.
From what we have seen so far, we could say that for practical purposes all the systems based on CodeSys are very similar, but it may be more comfortable for us to work with some than with others and I think that, rather than a question of performance, it would be a matter of habit.
Libraries are what make the difference.
What will really make one platform different from another are its libraries and in this case is where the famous PLCopen Motion Control comes into action, which almost all manufacturers implement.
Although they are the same, if we look at their function blocks, some may have small differences and offer something else that may or may not be useful, such as the MC_Power of the TwinCAT or the MC_Power of the EcoStruxure Machine Expert. One allows you to enable the axis so that it can only operate in one direction of rotation and the other in both. I have never come across a case in which being able to enable it in only one direction would have solved something for me, but I’m not saying that it couldn’t be useful in some very specific application.
Or in the SoftMotion libraries there is a detail that is very useful and avoids a few lines of code and it is the “ContinuousUpdate” input that, if activated, continuously monitors the input parameters so that if there is any change it is made. effective immediately. Without this input, the change in value must be detected by code and if it occurs, a new edge must be generated at the Execute input.
But in general, within what PLCopen Motion Control and SoftMotion are, it is very difficult to find important differences that make us opt for one or the other system.
Another thing is if, instead of PLCopen Motion Control libraries, we consider other libraries that are more typical of some manufacturers. The ones I know very well are those that come from the company that was the leader in packaging at European level, ELAU, which was bought by Schneider Electric and that are implemented by the equipment called PacDrive 3, the libraries called Axis Module. In this case, it is a totally different system that facilitates programming and offers much more, especially in the section of CAM profiles and the handling of rotary axes, you can see the great know-how that these libraries accumulate.
This is an important factor to consider when choosing the control platform.
Computers that have their own libraries usually also have PLCopen Motion Control libraries, so the programmer decides which ones to use.
Summary / Conclusions.
- The control platforms based on CodeSys are not identical, but they are very similar. It is difficult to find strong enough reasons to choose one or the other (without considering other aspects such as the product portfolio of each manufacturer)
- Motion Control libraries based on PLCopen Motion Control, including those from SoftMotion, don’t make a difference either, practically all of them offer the same functionality.
- Some manufacturers have additional libraries that offer greater performance and easier programming, such as Schneider Electric’s Axis Module, without excluding PLCopen Motion Control
- We will hardly be able to choose the most suitable platform considering only the small differences seen in this article. We will have to value other aspects more, such as product range and service.
