Siemens Simatic STEP 7

Historically, the languages for S7 were

STL = Storage Language (AWL in German) (equ. IL in IEC 61131-3)
LAD =  Ladder Logic (KOP in German) (equ LD  in IEC 61131-3)
CSF = Control System Flowchart (FUP in German) (equ. FBD  in IEC 61131-3)

These three came from the S5 world, and they are all included in the basic
STEP7 programming package. Also, they are (mostly) convertible, i.e. you can
write in CSF and switch to LAD or vice versa (well, in most cases ...), but
you can always use STL which is the "mother" of all the others.

Then there are add-on packages which are (among others) :

S7-GRAPH, a sequential flowchart, coming from GRAPH5 (or GRAFCET as named
elsewhere) (equ. SFC  in IEC 61131-3)
SCL = Structured Control Language (equ. ST in IEC 61131-3)
S7-HIGRAPH, a non-linear state diagram logic

Also, be aware - and this is most important - that you can mix the languages
(including the add-ons) as required, in any Siemens program. You can use the
language you feel most suitable for each task in the project.

Now, which languages are or can be used for "common machine control" ? This
depends - of course - greatly on the specific machinery we talk about, and
also on other factors like interchangeability (is IED 61131-3 a must?), and
perhaps also on other requirements like the possibility to migrate to other
platforms like AB or Mistubishi etc. pp.

If you ask for my personal favourite, I would suggest to have a look at
S7-Higraph. We use this language frequently for complex (handling) machines,
and find it very helpful. It is, however, neither standardized in IEC nor
interchangeable with other PLCs. - For simple (basic) logic we use LAD and
CSF, and for basic functions we (have to) use STL.

Hope this helps.

Btw. here is a link to the Higraph description
http://www2.automation.siemens.com/simatic/industriesoftware/html_76/produkte/software-s7-higraph.htm

Michael

Thanks for the answer. I will make some test ASAP. I'll get back and let
the group know which way I went.


--
Daniel