Displaying a graphical interface from a web browser

[Giancarlo]

I am using one SlimLine MPS052 * 100 programmable with CODESYS to which a mixed 20 I / O expansion module is connected. I state that I have installed CODESYS version 2.3.9.46 and I have made a program for the management of the digital and analog I / O of the expansion module. The program works well, both logic and analog inputs are acquired as well as both logic and analog outputs are managed.

The problem is that I can't view the visualization page from the Browser, I tried to download the latest java, with Firefox, Chrome etc. etc. Do you have any suggestions and / or example programs?

[Massimo]

Here is a sample program that manages all I / O of the 20I / O mixed signal expansion module, I have set up a web page of visualization and command, here it is screenshot view in the browser.

Warning ... The most common mistake is not to call the main WebVisu page by the name PLC_VISU. To view the page from the browser this is mandatory, then the other pages can have the name you want.

I enclose the complete project in which the program PLC_PRG (Print program) is performed by a task instead of being performed automatically, this avoids the appearance of watch dog errors (Project download).

[Fabio]

eseguito da un task anzichè eseguito in modo automatico, questo evita la comparsa di errori di watch dog…
What do you mean? Why should the watch dog error appear?

[Sergio Bertana]

Like all PLCs, too SlimLine has a watch dog control over the program execution time. Programs run automatically have a fixed and non-modifiable time. It has been seen that accessing from the web page lengthens the execution time of the program to the point that the watch dog control intervenes and stops its execution.

By executing the program in a task, it is possible to define whether or not you want to control the watch dog and / or define the time on that program. Hence the problem that an extension of the execution time causes the error is avoided.

[Andrea]

I developed an application with two web pages, the home with the famous name PLC_VISU and the second with the name PLC_VISU_SCHED on the home page there is a button that calls up the second page, up to here everything is OK, the home page works fine and all the values ​​are read and updated, on the second page a strange thing happens, all the fields present are not updated with respect to the values ​​present in the variables on the PLC, therefore all the fields present have the value "0".

I add that the input in the various fields works correctly and are stored in the respective PLC variables. Do you have any suggestions to solve the problem?

[Sergio Bertana]

I can't explain what your problem may be, meanwhile the problem also manifests itself in the debug window of the CODESYS environment or only in the browser?

I tried to do a simple project VisuTest that simulates the situation that you complain, but I have no problem whatsoever, try to run the project download and verify yourself.

[Andrea]

Actually the thing is very strange, the only difference is that in that page I refer to the variables contained in a data structure, the same one suggested in the forum for the management of the weekly scheduler.

PS The link above does not work, open a pdf.

[Sergio Bertana]

Thanks for the report I corrected the link. If you want you can send your project to support and we'll take a look.

[Alessandro]

Perhaps a stupid question: when I create web pages, with internet explorer, using Java, I can easily see them but with chrome I can't. Could the cause of the problem be that chrome no longer supports NPAPI?

Is there another way to see pages using Chrome?

[Sergio Bertana]

A question but do you use Explorer and Chrome on the same PC or on two different PCs? because usually the problem could be in the security setting in the Java panel (Screenshot). But this setting is common to all browsers on the same PC.

You took a look at this topic ?

[Moreno]

For a DataLogger project I tried to create a rather complex WebVISU page with about 80 variables. To work, the only problem is that when the page is open, the PLC slows down in a monstrous way.

My RUN led which normally flashes every second with the page open flashes about every 3 seconds. This is an intrinsic problem of CODESYS, I had noticed the same problem also on PLCs of other brands.

Another problem is that the JAVA applets are increasingly deprecated and even FireFox, starting from version 42, has definitively abandoned JAVA and to reactivate it you need to jump through hoops.

[Author]

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