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FAQ Machine manufacturers, programmers

 

Selmo Engineering

 

Are software, PLC and HMI replaced during retrofits?

 

Software always, PLC and HMI not necessarily. For retrofit projects, the technical status of the installed hardware must be assessed. If, for example, a TwinCat 3 controller with associated panel is installed, it is not necessary to replace the controller and HMI. However, if it is an older TwinCat 2 control unit, Selmorecommends  replacing the hardware, as support for these control unit types will expire in 2024.

 

 

Why replace functioning software?

 

Functioning software is rarely maintenance and user-friendly software. Older machines in particular, which have been in production for years and are to be integrated into a digital production system, present a challenge. The machines are usually not or only partially digitally visible. Selmo enables bit-precise diagnosis of the machine and thus reduces downtimes in the event of a fault. This cannot be guaranteed by manually programmed software.

 

 

What information must be known about the existing machine in order to be able to model it?

 

The machine process must be known, even if only in the form of videos and photos. This information is already sufficient to model the process in the logic layer. Ideally, the electrical diagram should be available for modeling in the "hardware level" grid layer. If not, then the majority can be modeled using an IO setup. Controls and information from subsystems are collected on site.

 

 

How can Selmo expand systems?

 

Selmo also offers the option of modeling and generating individual, independent step chains. For example, if a conveyor belt of a transport system is extended by a turning unit, the sequence for this unit can be modeled. The generated step chain is then integrated into the inventory software.

 

 

Can the software also be changed manually later?

 

Yes, the software can also be changed manually. However, this is not expedient, as any benefit of the Selmo method is lost.

 

 

Can safety-relevant PLCs be generated?

 

No. Safety programs must be created with the manufacturer-specific software. Selmo guarantees maximum functional stability and safety, but not in terms of personal safety.

 

 

Why is it advantageous or necessary to always monitor ALL bit patterns of a step chain?

 

This guarantees that the system is in the exact expected state and that no unnoticed deviations occur. This requires a sufficient number of sensors in the system to be able to monitor every status. This guarantees the maximum functional stability of the software.

 

 

What does the Selmo method do for my engineering?

An engineering boost. For you, your partners and your customers. Conventional, modern system modeling sometimes reaches its limits because production systems are becoming increasingly complex. Many interfaces offer many potential sources of error. The Selmo method is different: it starts directly with the requirements description. The process is the focus, serves as a common view of the system and is also the model from which the system software is generated. Because interfaces are eliminated, engineering time is significantly reduced and the scope for interpretation is minimized. This is how Selmoleads  to a major increase in efficiency and quality.

 

 

 

Selmo studio

 

What does the free engineering tool Selmo studio do?

 

The creation of step chains and PLC software is faster and easier with the innovative modeling tool. Selmo studio reduces the complexity of PLC programming to the essentials: What should the machine do and how is it mapped? Once the programmer and process expert has understood the simple principles of Selmo, Selmo studio is an engineering turbo.

 

 

How much faster is Selmo than manual programming?

 

As an experienced programmer, you can program a simple step chain with a few cylinders in around three to four hours - if you know the process flow and how a step chain works. With Selmo, you only need to model the processes and assemblies and link them via the BitControl. Then you can quickly generate and import them into the PLC. The HMI is automatically generated from the programming code. An HMI developer would need several hours for this. If existing processes are required on different PLCs, then a generic model of the process is ideal. With Selmo studio and the generator for different PLCs, Selmo supports machine builders who today have to program different software for the same mechanics.

 

 

What are the main functions of Selmo studio?

 

Selmo studio implements the Selmo standard. It is a modeling tool, PLC and HMI generator in one. With the modeler function, you can create step chains (finite automata) and document your machine system digitally. It uses discrete state modeling for this. Transition-related sequence programming is no longer necessary. The integrated generator creates the sequence logic software and the user interface fully automatically. Unlike other solutions, Selmo allows you to process and display every possible bit pattern of a step chain.

 

 

What are the main advantages of Selmo studio?

 

It is available for free download, including demos and modeling examples. With Selmo studio, inputs and outputs are modeled as zones. The modelled sequence with all steps and zones is generated directly as standardized, error-free and hardware-independent PLC code in accordance with IEC 61131-3. In future, programmers will be able to import the code into any controller type that complies with this international standard. Selmo studio generates not only the syntactically error-free PLC code from the sequence description, but also the HMI. The operator receives a standardized, system-independent operating concept: A Selmo system provides information at all times on what is currently happening, what needs to be done and what is missing in the event of a fault. Selmo minimizes downtimes for your customers and maximizes system availability. This increases customer satisfaction. You gain more focus for your successful tasks.

 

 

What are the benefits of Selmo modeling?

 

Up to now, process and machine sequences in graphical form have usually served as the basis for programming the sequence. The description is doubly complex: First graphically-informally to create a common understanding of the process and then formally in PLC code for realization. With Selmo studio, PLC and HMI code is created directly from the process description. Only sensors and actuators need to be assigned to the individual steps in the grid layer. As a result, the process engineer-programmer interface disappears completely; the duplication of effort is eliminated.

 

Does generating also help me with software checks?

 
Unit and integration tests are carried out conventionally to check software for errors. Standard syntax checks detect many manually caused "typos". Logical or syntactically correct typing errors, however, must be laboriously searched for using unit tests. In order to find any deviations from the graphically described process, these have to be restarted after every software change. Selmo studio takes over this translation work for you and generates syntactically correct, error-free software. As with any other programming or modeling method, the process steps must of course be formulated correctly in advance.

 

 

How can I imagine the generation of the HMI?

 
Selmo studio generates not only the PLC code from the model, but also the HMI. Inputs and outputs are modeled as zones. You can define which zones require an HMI button for operation. The modeled sequence with all steps and zones is generated directly and the diagnostics are derived from it. The operator or your customer receives a standardized, system-independent operating concept. There is no longer any system downtime for maintenance without an error message. Each step chain reports the error and indicates what is missing in order to continue switching. In this way, Selmo studio minimizes downtimes and maximizes your customers' system availability.

 

What is the benefit of always using the same Selmo software structure?

 
In order to make the software maintainable, large plant operators specify software standards or structures. These specifications have to be implemented at great expense and adhered to consistently. After all, acceptance is the goal. PLC code generation with Selmo studio, on the other hand, automates compliance with the standard: The code always has the same structure, regardless of function. The Selmo standard makes the code easy to understand, as it is always structured in the same way - whether for an assembly line or a woodworking machine.

 

 

How do my customers and I benefit from hardware-independent software design in accordance with IEC 61131-3?

 
The same systems often have to be supplied with different control systems for different target markets because many system operators rely on a single control system. The software has to be rewritten or manually adapted for each required control system. Selmo studio, on the other hand, generates the PLC code in accordance with IEC 61131-3, allowing programmers to import the code into any type of controller that complies with this international standard.

 

 

Is there a support team that I can contact?

 

Yes - but we assume that you have general PLC programming knowledge. The Selmo support team is available by e-mail support (to  einfach@selmo.at) or via our contact form(https://selmotech.com/de/contact-us) from 9:00 to 15:00. We will be happy to make you an individual offer for workshops, training and consulting. Selmo license partners receive free training and ongoing support.

 

 

I want to give user feedback. Where do I go?

 

We are a start-up that makes our tool available to you at low cost. Our innovation is constantly being developed further. We therefore look forward to your feedback. It doesn't always have to be positive. On the contrary: we learn from the toughest critics. Use our contact form(https://selmotech.com/de/contact-us) to tell us what you would like to see in the next versions of Selmo .

 

 

Is Selmo training material available?

 

 

We offer individual training courses online and offline - at your premises or directly at our premises. Training is provided on the Selmo way of thinking about processes. Tutorials with application examples are being planned and will be  publishedstep by step in our Help Center (helpcenter.selmotech.com). Use our Selmo demo there to get a first impression of the Selmo benefits. Further functions and practical examples will follow. We want to respond to the market and its needs - and not the other way around.

 

 

What basic knowledge do I need to model and generate step chains with Selmo studio?

 

Basically, Selmois  easy to use. Even process engineers with little PLC knowledge can use it to model simple step chains and generate them with a single click. The challenge lies in rethinking the process logic based on transition conditions in favor of state modeling. If the process has been thought through logically and precisely, most of the work is already done for simple step chains. For larger systems or retrofit projects, the expertise of Selmo system engineers and licensees is  required. The implementation of PLC programs requires experience with PLC development environments. Our support and the planned tutorials enable you to implement simple applications yourself.

 

 

Do I have to generate with Selmo studio or can I just model and then program manually?

 

You can just as well just model and program yourself. Our tool is an aid for digital project planning and for quickly creating PLC code for step chains. Always implement step chains automatically in the same structure, without deviations due to individual programming. Use our tool as you need it. It can be used and tested free of charge.

 

 

How do I get the exact sequence logic of the machine?

 

The sequence logic is derived from the informal process description and is based on the description of the machine sequence. It is simple step-by-step thinking without the distraction of driver details. With Selmo, we achieve  a common understanding for everyone involved from the very first moment.

 

 

How can step chains be executed in parallel? 

 

 

Which signals should be monitored and how are they defined? 

 

 

On which control systems does Selmo studio already run with the integrated code generator?

 

The Selmo model itself is hardware-independent. Selmo studio currently supports all controllers based on the TwinCAT 3 system from Beckhoff. Our development experts are working on supporting other controllers. As of January 2021: Integration into the CODESYS software platform is on the verge of a breakthrough. Work is underway on further CODESYS-based PLCs. As Siemens does not support the import of PLCOpen, Siemens will be specially integrated on request. Selmo strives for platform independence for its customers and license partners and prefers open systems as a first step.

 

 

Is the generated PLC code readable for the PLC programmer?

 

Except for the core blocks, which are in a compiled library, the generated PLC code is readable. You receive machine software that is generally understandable. The PRG block is a structure that is easy to understand. The integration takes place via the block call and the individual inputs and outputs are attached to the block. The function block works like a switching mechanism and is comparable to an IC. When the inputs are connected, the logic reacts with the outputs and display information. In principle, we rely on diagnostics on the HMI instead of an online search in the program code.

 

 

Do changes always have to be made with the code generator?

 

No, changes do not necessarily have to be made in the code generator. However, we at Selmo recommend it, because any change to the generated PLC code can jeopardize the system integrity.

 

 

Is it possible to read back code - for example due to manual changes?

 

No, reading back code is not possible and not intended. Changes to the logic should always be made via the process, via the model and generator.

 

 

How do I access Selmo studio and the Selmo demos?

 

You can register for Selmo studio free of charge and without obligation in our download area, download 3D demos and test Selmo in practice: https://selmotech.com/de/demo-downloads

 

 

Do I pay for generating or for modeling?

 

Modeling can always be tested free of charge, including the generation function. You can test the system for a short time using your step chain. You also benefit from all Selmo functions during the test phase. The step chains are generated in a PLCOpen XML file, which is simply imported into the PLC. You only pay once you are satisfied that the step chain runs. You can then apply for a license key(https://landing.selmotech.com/selmo-studio). The offer for your step chain will be sent to you. You only pay once you have accepted it.

 

 

How much does a step chain cost?

 

You pay for the generator's performance based on the number of steps and assemblies in a step chain. You will receive a quote for this when you apply for the license key. An online calculator for calculating step chains is planned.

 

 

How do I get the step chain to run for an unlimited time?

 

Via a license key, which you can either request yourself in the "Selmostudio" tool - or via our website: https://landing.selmotech.com/selmo-studio

1. you have downloaded the free Selmo studio, modeled it and generated the PLC code.

2. you have transferred the PLC code to the target system.

3. you can read out the request ID there. You need this to be able to use the PLC code generated by Selmo for an unlimited period of time.

4. fill out the form with all the required information and send it to us.

5. you will receive an offer from us and an invoice upon acceptance. The amount depends on the number of sequences, steps and zones to be licensed.

 

 

Do I have to pay for the step chain each time I generate?

 

No. The calculation is based on the number of steps and zones. You only ever pay the difference to the amount already paid.

Example 1: Sequence costs € 599 - you extend the sequence (step chain) accordingly - new sequence costs = € 700 - you pay € 201 to use the new sequence.

Example 2: Sequence costs € 599 - You change the order of the steps in the sequence (step chain) and the name of the zones = € 599 - You pay € 0 and can use the newly generated sequence immediately.