wlederer

What is the benefit of using Structured programming?

30 posts in this topic

I am not sure, that this is specific to Mitsubishi. Does anybody compared other  PLC performance running structured versus traditional? I don't remember such reports.

Generally, the idea of structured programming is good. But, in reality, the big PLC manufacturers have no interest in investing money for improving their tools for structured programming. Most programmers use ladder anyway, because it is simple and works fine.

Why should managers hire engineers and spend extra money? Will income increase? I compared Mitsubishi FX and found that the ladder program perform better. It is possible that with Mitsubishi Q or L result will be different. It depends on compiler. 

Generally, the problem is that the hardware is not standardized. The automation market is badly segmented and investment in the software standardization does not make profit.

 

Share this post


Link to post
Share on other sites

Dear wlederer,

1. The PLC manufacturers has an interest in big sales. The structured programming reduce the time for project development and it's comissioning, especially if the project has a huge volume. Thus, the system integrators are able to implement more projects in the same time interval, i.e. they will use more SPS during the same period. Other words, the goal of investment is present for both sides (manufacturer and customer), both will get more money profit in annual.

2. You may ask, why the first item does not work? 
The PLC manufacturer managers does not understand anything in PLC programming issues. The developers of programming software tool does not understand anything in it too. Only software engineer may know in what he is really need! That to obtain a good result in programming software development a close feedback from the PLC engineers is necessary. But the first pair is convinced that they are much more clever and coolest than the last.

3. Even if the PLC manufacturer has managed to create a successful development tool, it's not enough for the final effect (to increase the profit). It's need to organize an effective education for its customers, i.e. for the PLC programmers, working for system integrators. But how the manufacturer can do it, if he does not have an own department of automation project development thus own engineers (teachers) does not have an experience of implemention real projects?? In this case such education of wide circle of customers can be provided only with participation of talented PLC programmers, working for system integrators, that are alone learned and tested all possibility of the SW. But what system integrator would like to multiply competitors for himself??  

I could share here with items 4, 5 etc. that prevents for Mitsu (and some other manufacturers) to create an excellent programming tool. And for customers does not allow to get and use a good programming tool, to get a good education and knowledge in effective using of new programming products and all their capabilities. But for whom these arguments will be useful?..

***

If you or somebody else there want to feel and understand in what are the benefits of structured programming, I could offer two way. The first is I can share the ready programs, written by me, that it might given a chance to learn and analyze the technique of programming alone. The issue for english speaking people is all comments in these programs are in Russian... The second is a tutoring. This way requires a time and serious efforts by my side. The advantage of this way is that together we will develop a new existing project(s). The drawback is that this way is costly for pupils, because a time of tutor and his nervous is the money. 

For a PLC programmer has a meaning to pay from own pocket for this tutoring in case he'd like to rise his level higher and to leave from the current company to get a higher salary. For the employer has a meaning to pay for the tutoring in case he understand that such tutoring will bring him a greater money than he spent. In practice, the first category is not ready to pay, at minimum, due their current salary does not allow to pay for the tutoring, both and they are don't sure that it will allow to find a better job. The second category don't ready to pay, because: 1) they are don't feel and understand a huge difference between seminars and workshops, providing by PLC manufacturer, and a tutoring; 2) they are prefer official certificates by manufacturers in comparision to get a market superiority on which they are making money;3) they are not sure that when they will spend the money for study of the employe, they are not losing the spent money toghether with the employe...

Kind regards,

Share this post


Link to post
Share on other sites
On 8/2/2018 at 9:47 PM, ParaffinPower said:

I think this is a problem specific to Mitsubishi, confirming my opinion that it should be thrown in the bin.

I agree.....Used GX IEC for years and found it shocking at times.

Used TrioBasic which helped me develop text based programming -

And now I use Omrons Sysmac Studio - i like the ability to use ladder and Inline ST very useful -

Horses for Courses - while SS isn't perfect - The problems i used to have with GX IEC and Mitsubishi in general seem like a distant memory.

Share this post


Link to post
Share on other sites

Why use Structured Text (ST) programming for your PLC applications?

ST is a very flexible and universal programming language. ST program code can easily be copied between different PLC types and be sent via e-mails as it is based on text and not graphics as the LADDER programming does. 

The ST program code is similar to text sentences and work is carried out the same way as a word processor program (as e.g. Microsoft Word) which makes it easier to work on. Consequently, the same working methods are applied as in a word pro-cessor program. 

Because of its very structured nature, ST is ideal for tasks based on complex math, code reuse or decision-making (e.g. automatic energy optimization, algorithms, data collection and regulation). 
Having the experience with PLC Programming the transition to other programming languages within PLC Control and automation will be easier; i.e. programming ro-botics or Visual Basic Programming.
Within later years still more companies have switched to ST Programming which is due to the fact that ST provides a series of advantages compared to the four other PLC programming languages (LAD, SFC, FDB and IL).

These advantages are as follows: 

- ST Programming code can relatively easy be copied between different PLC types.
- It is the easiest PLC language for mathematical calculations, formulas and algorithms and large amounts of data (bigdata) 
- PLC solutions are more demanding today than 20 years ago 
- Many widespread PLC programming languages (C++, C#, PASCAL, VB) reminds very much of the ST program structure. 
- The other PLC languages (LAD, SFC, and FBD) require that parts of them are programmed in ST. 
- It takes up less space when the PLC code must be documented, described and printed compared to the other PLC languages. 
- It is easiest PLC language to version control via comments in the program code or via GIT or Subversion 

Reference: The book “PLC Controls with Structured Text (ST) - IEC 61131-3 and best practice ST programming”

Share this post


Link to post
Share on other sites
12 minutes ago, Empty said:

Why use Structured Text (ST) programming for your PLC applications?

The Structured Text and the Structured Programming are completely different concepts.

1 person likes this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now