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Webserver s7-1200 fails to update tags in web-browser with use of javascript

Created by: Software Engineering at: 9/18/2014 11:15 AM (6 Replies)

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9/18/2014 11:15 AM	Rate (2)
Software Engineering Posts: 5 Rating: (5)	Dear all, Situation: The main goal is to change the e.g. background of the web-browserby usingthe :="Output_0": boolean from the PLC. As you can see the script is updating every second. If I display the :="Output_0": boolean in just HTML, the value is visible (0 or 1) but only updates when F5 get pressed and not automatically every second. Problem: The :="Output_0": boolean won´t automatically update. It is only updating by using F5 or meta refresh. Question: How can we update a PLC boolean automatically without using F5 or meta refresh? Thanks in advance for all the suggestions/answers. IO_Variable.html ================= <!-- AWP_In_Variable Name='"Output_0"' -->:="Output_0": Index.html ================= <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>Webserver Website - Test Application</title> <meta http-equiv="Content-Language" content="en" > <meta http-equiv="Content-Type" content="text/html; charset=utf-8" > <meta http-equiv="Content-Script-Type" content="text/javascript" > <script src="Script/jquery-2.1.1.min.js"></script> <!-- <meta http-equiv="refresh" content="1; URL=Index.html"> --> <link rel="stylesheet" type="text/css" href="Stylesheet/Stylesheet.css"/> </head> <script type="text/javascript"> // Reload the data from IO_Variable.html automatic $(document).ready(function(){ //query the variable every 0,1 second $.ajaxSetup({ cache: false }); setInterval(function() { $.get("IO_Variable.html", function(result){ $('#Variable').text(result); }); },100); }); var test = 1; var tmp; function setbackground() { window.setTimeout( "setbackground()", 1000); // 1000 milliseconds delay var ColorValue = "FFFFFF"; // default color - white (index = 0) //tmp = Math.round(Math.random() * 1); tmp = :="Output_0":; if (tmp == test) { ColorValue = "00FF00"; } if (tmp != test) { ColorValue = "FF00FF"; } document.getElementsByTagName("body")[0].style.backgroundColor = "#" + ColorValue; } </script> <body onload ="setbackground();"> <p align="center" style="margin-top: 100px"> <font size="100" face="sans-serif"> <label id="Variable" name="Variable">:="Output_0":</label> </font> </p> </body> </html>
Software Engineering Posts: 5 Rating: (5)	Last edited by: Software Engineering at: 9/18/2014 11:33 AM Last edited by: Software Engineering at: 9/18/2014 11:28 AM
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9/18/2014 11:19 AM	Rate (0)
AutoGen_685543 Member Joined: 11/19/2013 Last visit: 3/10/2020 Posts: 1 Rating: (0)	I have the same problem. Hopefully somebody can help!

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9/18/2014 12:40 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 11/18/2024 Posts: 15405 Rating: (2446)	You both are assuming the tiny web server in the s7-1200 family is just like every other web server and has live data. It does not. Others have posted some tools and techniques to use additional frames and such to update data in a hidden frame and display somewhat live. However, be aware the web server requires a lot of cpu time as well as greatly increases the communications load on the PLC. This will affect your plc program running speed (scan time). If you need more web server speed, there is a plc configuration setting to increase communication load support. The default is 20%. It may need to be higher, perhaps 30-40% depending on how often and how many tags you are updating. Check the forums for user provided answers to your questions. They already exist but I do not have them bookmarked. I know the limitations of the plc and would generally prefer the program to run faster and use an HMI rather than a web page to inform and communicate with the end user.
	science guy
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9/18/2014 4:30 PM	Rate (1)
Software Engineering Posts: 5 Rating: (5)	Hello, Thanks for the answer. The other forum items you suggest tell something about a page refresh but not anything about a PLC variable refresh (which is specific to Siemens). Idon’t have any problems with refreshing the webpage (also not with iFrames), butI have a problem with refreshing the PLC variable. As you can see in the example project, the JavaScript page refresh is working perfect, but the PLC variable is not read again during the page refresh. The main questions remains: - How can we automatically update a PLC variable in the webserver/web-browser without using F5, meta refresh or a button on the screen? - What is the correct declaration/notation of a variable in JavaScript? ( HTML is :="Output_0": , but JavaScript is ??? ) - And why is the PLC variable not updating in the JavaScript refresh update loop? Is this maybe a malfunction in the Siemens Webserver which can be solved in a firmware update? Thanks!
Software Engineering Posts: 5 Rating: (5)
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9/24/2014 12:59 PM	Rate (0)
D_Craig Member Joined: 11/28/2013 Last visit: 9/11/2024 Posts: 10 Rating: (0)	Hello, there is an example for automatic update with java for S7-1200 under following link http://support.automation.siemens.com/WW/view/de/58862931 It runs with IE11. For Firefox you have to replace in file "Data_String.js" the ID "Data_string_frame"with the name "PLC_Frame" in 5 cases. and one example for S7-1500 http://support.automation.siemens.com/WW/view/de/68011496 Maybe it helps you BR

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9/24/2014 1:16 PM	Rate (0)
Kahl Platinum Member Joined: 12/16/2012 Last visit: 11/14/2024 Posts: 654 Rating: (130)	Hi! Have you seen this? https://www.dmcinfo.com/latest-thinking/blog/id/8567/siemens-s7-1200-web-server-tutorial--from-getting-started-to-html5-user-defined-pages
	ALPHR Technology Europe
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9/24/2014 3:31 PM	Rate (2)
Software Engineering Posts: 5 Rating: (5)	Thanks for the feedback. Yes, I have seen all the examples you suggest. But in non of them I can find how to update a direct boolean like :="Output_0": without using F5, meta refresh or iFrames. The example shows indeed how to update a value and displaying it on the screen (that works in my test project), but I would like toupdate the:="Output_0": with javascript in order to use it in a function like: tmp = :="Output_0":; if (tmp == test) { ColorValue = "00FF00"; } The question remains:automatic refresh the:="Output_0": boolean with javascript like shown in my previous posted test project without the use ofF5, meta refresh or iFrames. Itseems to bedifficult and I'm wondering if it is actually possible with the current webserver firmware.
Software Engineering Posts: 5 Rating: (5)
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