Siemens SIMATIC S7-1200 - Page 1080

Web server
12.7 User-defined Web pages
S7-1200 Programmable controller
1080 System Manual, V4.2, 09/2016, A5E02486680-AK
Struct members of requesttab struct
Block tag
Data type
Description
page_index
UINT
Number of the current web page
fragment_index UINT Number of the current fragment - can be set to
a different fragment
// Request Commands
continue BOOL Enables current page/fragment for sending and
continues with the next fragment
repeat BOOL Enables current page/fragment for resending
and continues with the same fragment
abort
BOOL
Close http connection without sending
finish BOOL Send this fragment; page is complete - do not
process any additional fragments
// Request states
The request states are read-only
idle
BOOL
Nothing to do, but active
waiting
BOOL
Fragment is waiting to be enabled
sending
BOOL
Fragment is sending
aborting
BOOL
User has aborted current request
Operation
Whenever your program makes changes to the control DB, it must call the WWW instruction
with the number of the modified control DB as its parameter. The global commands and
request commands take effect when the STEP 7 user program executes the WWW
instruction (Page 1059).
The STEP 7 user program can set the fragment_index explicitly, thus causing the Web
server to process the specified fragment with a request command. Otherwise, the Web
server processes the current fragment for the current page when the WWW instruction
executes.
Possible techniques for using the fragment_index include:
● Processing the current fragment: Leave fragment_index unchanged and set the continue
command.
● Skip the current fragment: Set fragment_index to 0 and set the continue command.
● Replace current fragment with a different fragment: Set the fragment_index to the new
fragment ID and set the continue command.
To check global states or request states that might be changing, the STEP 7 user program
must call the WWW instruction to evaluate the current values of these states. A typical usage
might be to call the WWW instruction periodically until a specific state occurs.
Note
If the STEP
7 user program sets more than one request command, the WWW instruction
processes only one in this order of precedence: abort, finish, repeat, continue. The WWW
instruction clears all of the request commands after processing.