[?]: OBs in S7-300 program

SIMATIC S7-200/300/400, Step7, PCS7, CFC, SFC, PDM, PLCSIM,
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Location: Pakistan

[?]: OBs in S7-300 program

Post by VINESH KUMAR » Sun Nov 14, 2010 7:23 am

Dear all

I am new in plc s7-300 i have made a program for our plant with cpu 313c i use only ob1 to call functions.i neeed help which other obs should i use for best performance and how please help

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Re: OBs in S7300 PROGRAM

Post by mogz » Sun Nov 14, 2010 11:28 am

Depends what you want / need to do in your program.

OB's include -

OB 10 - 17 Time of day interrupts
OB 20 - 23 Timed interrupts
OB 30 - 38 Cyclic interrupts
OB 40 -47 Hardware Interrupts
OB 80 - 87 Asynchronous Error Interrupts
OB 102 - 101 CPU Start Up

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Re: [?]: OBs in S7-300 program

Post by sanruku » Mon Nov 15, 2010 9:08 am

VINESH KUMAR wrote:I am new in plc s7-300
Hi & welcome in the exciting world of SIMATIC programming.
As you may know, SIMATIC is manufactured by Siemens, a very big company, known all over the world.

So, there are some bad news & some good news about that.

First, the bad news:
PLC programming as a science as well as an art. This means that you have to:
1) read a LOT of manuals
2) read a LOT of code
3) have a good knowledge of engineering
4) write a LOT of programs

This means that you have to be always up-to-date, always learning new stuff and always do your own research.
It also means that is a difficult profession.

Well, the good news about that is that you can learn a LOT by visiting this - really big - site:

Take your time to navigate through it, there are literally millions of pages providing real application examples, manuals, FAQ, and last but no least the "FORUM"!!!...

So, it is a wise move to register yourself in the "FORUM", and start using the most exciting invention since man first created fire:
the SEARCH function!!!!

As I said, at first it can be difficult - even intimidating - for a newcomer to get a hold of the site...
But be patient, grasshopper, and you will soon find that all this knowledge is freely available by the wise PLC creator...
(although not all of it freely, but there are other places that solve that minor problem)

Oh, I nearly forgot: the best part of this particular profession (apart from the engineering title) is that YOU'RE GETTING PAID ENOUGH!!!

So, although one is new to the game, one should invest time and effort and all good things in order to learn.


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