STEP 7 - Monitor FC with call up path

[DrDrreeeaaa]

Hello All

Does anyone know how to monitor a specific instance of an FC in STEP 7?

I have read the Siemens documentation, about specifying the call environment... I don't really understand it, practically.

For instance, it talks about specifying a block call up path for monitoring the FC. What if there are more than one FCs in the block that is described in the call up path?

And how does it work when you specify a DB in the call up path window? Is this only for FBs or does it have some relevance to FCs?

Thanks

Michael

 

[djs]

Depends on the S7 processor. The S7-400 can not monitor a FC. The S7-300 can. In the S7 logic editor, right click on the instance of the FC you want to monitor and a pop-up menu will appear allowing you to open a monitoring window.

 

[controlsdude]

there is a monitoring tool where you just add variables that you want to see for any fc, fb, etc... Its part of the step 7 program.

 

[ceac]

First, there is some confusion between FCs and FBs.

An FC is a block of code without non-volatile memory. You can define variables inside the FC, but once it finishes processing the variables are erased from memory.
An FB is the same thing as an FC with the exception that you give it a DB to be it's own non-volatile memory.

So, you can monitor an FC and the results of an FC anywhere. If you are connected to your PLC, you can open the FC (or the FB/FC that contains the FC you want to monitor) and click on the glasses in the menu bar of the code editor.

FBs are a bit more complicated. You can call the same FB with different DBs (instance DBs) and therefore have different results. So to monitor an FB, you open the FC/FB that contains the FB you want to monitor and right click on the line that has the FB. Normally something like CALL FB250, DB250. On the pop-up menu a Monitor selection will be available. Clicking it will let you monitor the FB with the desired DB.

Hope to have helped.