Constraints Specific To User-Defined Web Pages - Siemens SIMATIC S7-1200 Manual

Also be sure to also save the file from the editor in UTF-8 character encoding:
You use STEP 7 to compile everything in your HTML pages into STEP 7 data blocks. These
data blocks consist of one control data block that directs the display of the Web pages and
one or more fragment data blocks that contain the compiled Web pages. Be aware that
extensive sets of HTML pages, particularly those with lots of images, require a significant
amount of load memory space for the fragment DBs. If the internal load memory of your CPU
is not sufficient for your user-defined Web pages, use a memory card to provide external
load memory.
To program your HTML code to use data from the S7-1200, you include AWP commands as
HTML comments. When finished, save your HTML pages to your PC and note the folder
path where you save them.
Refreshing user-defined Web pages
User-defined Web pages do not automatically refresh. It is your choice whether to program
the HTML to refresh the page or not. For pages that display PLC data, refreshing periodically
keeps the data current. For HTML pages that serve as forms for data entry, refreshing can
interfere with the user entering data. If you want your entire page to automatically refresh,
you can add this line to your HTML header, where "10" is the number of seconds between
refreshes:
<meta http-equiv="Refresh" content="10">
You can also use JavaScripts or other HTML techniques to control page or data refreshing.
For this, refer to documentation on HTML and JavaScript.
9.3.2

Constraints specific to user-defined Web pages

The constraints for standard Web pages also apply to user-defined Web pages. In addition,
user-defined Web pages have some specific considerations.
Load memory space
Your user-defined Web pages become data blocks when you click "Generate blocks", which
require load memory space. If you have a memory card installed, you have up to the
capacity of your memory card as external load memory space for the user-defined Web
pages.
If you do not have a memory card installed, these blocks take up internal load memory
space, which is limited according to your CPU model.
You can check the amount of load memory space that is used and the amount that is
available from the Online and Diagnostic tools in STEP 7. You can also look at the properties
for the individual blocks that STEP 7 generates from your user-defined Web pages and see
the load memory consumption.
Note
If you need to reduce the space required for your user-defined Web pages, reduce your use
of images if applicable.
Easy Book
Manual, 11/2011, A5E02486774-04
Web server for easy Internet connectivity
9.3 Easy to create user-defined web pages
185