Tips for Programing Simatic Step7

Hello Long;

Once you have worked through the tutorials proposed by William_B, you could also have a look at the following Application Examples generated by Siemens for the S7-300. There are over 500 of them, and they are somewhat similar in design to the S7-200 Tips and Tricks:

https://support.industry.siemens.com/cs/search?ps=100&search=s7-300&type=ExampleOfUse&lc=en-WW

Hope this helps,

Daniel Chartier

Hello, 

First be sure of a fact that you won't know all tips and tricks.

Actually nobody can.  Simply if you decided to read all S7 manuals, Step7 will become obsolete before you finish. 

What I would like to say that experience will learn you alot, reading more and more, and reach to the solution of your problem in a very short time.

Finally please have a look at this link. 

Hello,

Try this link. 

Hi

In a nutshell:

1. Name things in consistent way - you will be able to find them easier after a time:

physical inputs: I_XXX (provide schematic indnet in the name so you have cross-reference

program vs drawings)

outputs: Q_XXX

FC/FB Inputs/Outputs/InOuts/Stat/Temp: I_XXX, Q_XXX, IQ_XXX, UPPERCASE, MixedCase

this way you will see in the code what is what in the FC/FB (if it is fc inout/output/local variable)

Analogues:

They have raw scaling 0..27648 (or -27648..27648). use SCALE function to convert them to

engineering units

NOTE: for 4..20mA inputs ignore small negative values (up to -1000) - if value is much lower

flag wire break.

When Input shows +-32767 flag an error.

for Outputs use UNSCALE to convert from engineering units back to analog output format.

most important OB blocks (OBs are called by operating system):

OB1 - main block

OB35 - time interrupt (called at fixed intervals, usually 100ms)

OB100 - PLC restart (called once when PLC powered up)