S5-->S7

I want to convert a software from S5 (95U)to S7 (300).Some of addresses that in Block address list were used.Like this;

:L KH 7EB4 ( DB90 )
:LIR 0
:L KF+0
:!=F
:R C 0
:BEC
What is the equivalent of this part in S7?

Another question;
In OB1
:JU PB1
:JU PB2
:JU OB31 ( reset watchdog timer )
:JU PB3
:JU PB4
:JU OB31 ( reset watchdog timer )
etc...
What is the equivalent JU OB31 in S7?
Thanks in advance...

Hello tulip;

There is no exact equivalent to the LIR/TIR (Load/Transfer Indirect Register) in S7. There have been better explanations on earlier threads that I can give, for example here:
http://www.plctalk.net/qanda/showthread.php?t=39561&highlight=LIR

To reset the watchdog timer, you can have a look at SFC43:
4 SFCs for Controlling Program Execution

Description​

​

With SFC43 "RE_TRIGR" (re-trigger watchdog), you can re-trigger the cycle time monitoring.​

Look it up in the Standard and System Functions manual. But in general S7 systems do not require the watchdog timer to be reset, this was a limitaion of smaller S5 systems when too many blocks were being called at the same time.
One thing you have to ensure to get a good conversion is an understanding of the platforms you are converting from, and converting to. Much code in the S5 is now taken care of in the S7 processor directly.

Hope this helps,
Daniel Chartier

The S5 DB90 part is testing to see if DB90 exists, here is the equivilant in S7:

Can you help me about how to use an SFC 24 ?

Hello tulip;




Hope this helps,
Daniel Chartier

Thanks for your efforts..