New to Siemens S7......and programming

[scimdarren]

Thanks, very good site that I have not stumbled on yet, unfortunately,
the module did not cover my issue.
I want to save/manually enter a value in a memory bit double word, once I have done this I want to use an FC106 or FC105 (scaling functions) to give me my signal.

My problem is a lack of understanding of how to enter the value?

Many Thanks

Darren

 

[JesperMP]

You probably want to use the FC106 (Unscale) function.

You must have a REAL variable with the engineering value, and it will be converted to a WORD that should fit the typical range of the analog output cards (-27648 .. 0 .. +27648). You must specify the HI_LIM and LO_LIM that is the range of the analog output, "100.0" and "0.0" for an output that must go from 0-100% for example.

When you find the FC106 in the standard library under TI-S7 converting functions, highlight it and hit F1 to get help on the usage.

 

[scimdarren]

Thanks, SFC106 worked!
Right, now I actually want to perform PID, out of the frying pan and.....!
I have just opened SFB41, a PID block, how to I address it? I get 3 red question marks that I cannot extinguish? How do I get round this?

Darren

 

[JesperMP]

Every time you get the red question marks on an IO pin, put the mouse cursor over the pin, and STEP7 will tell you which type(s) the variable on the pin can be.

 

[SimonGoldsworthy]

If the three red question marks are above the block (assuming you are using ladder), this is where you enter the instance data block number. An instance data block is required for function blocks as they use the data block for storing their i/o parameters as well as static data. You can minimise the number of data blocks in use by using multiple instances - if you need to use these and are not familiar with them, ask when you hit a problem and I'm sure you will get some more help.

 

[scimdarren]

Thanks... to everyone that has replied so far, please bear with me, the pdf manuals are vast and time consuming to find info during the working day, that is why I am very grateful for the 'quick' answers I get here!

Unrelated to my last post, I appear to have a bug in my program:

On opening my project, I get the window:
The project '30805' contains errors in the internal data structure

When clicking on Details:

S7KAFAPX.EXE: Internal error during saving (action 'LAD/STL/FBD') of the data of server 'S7xautomx.dll'

Anyone encountered and dealt with this before?

Darren