asm stl instruction

Hi,

These FB's used to be coded in STEP5 but this takes up a lot of user memory space.

To save memory space Siemens have hard coded the FB's directly in the operating system memory not in program eprom.

The command in all of the hard coded FB's is ASM KH0000 because there is really no S5 command in the languageavailable for what it is doing. What is actually does is jump to a system memory location and run probably a bit of machine code.

All you get as a user is the parameter interface. These are the parameters you must pass to the FB and the parameters it will return after it has run.

You cannot look at the code or modify it or delete it.

The example you have MUL16 is a Muliplication block because the processor is not capable of multiplying large numbers.

The S5 manual for your specific plc will explain the FB parameters and how to use it and will be available to download from the Siemens website.

Hope this helps

Shanny

New questions published by Hazzem is split to a separate threads with the subject

• can be the RET_VALUE the time of the previous cycle of OB1. and
• Is the compress fuction in S7 executable or not in the OB1?.

Best regards
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