S7 - Using FC Parameters

JayD

Member
J
Join Date
Aug 2009
Location
Australia
Posts
53
Hey All,

Hoping for some help with using FC parameters as parameters for another 2nd FC within the 1st FC.

I understand that FC parameters are passed as DB pointers and am unable to directly use them as an input parameter to another FC.

What I currently do is to copy the parameter to temp and then use the temp as the new parameter. Can anyone suggest a better alternative?

Cheers
JD
 
All FC parameters are passed as Area pointers, not DB pointers. Can you post a simple example showing the passing on of parameters ?

Create your example code, create a new library (as opposed to a project), insert an S7Program into the library then copy the blocks to the library. Archive the library and then attach to your post.
 
My issues is again with UDTs, not with basic elements. A UDT parameter(In or In_Out) of a main FC can't be used as an In to a sub FC. See the example code...

Is there a way of copying the pointer and providing that as the input to a sub FC?
 
JayD said:
Is there a way of copying the pointer and providing that as the input to a sub FC?
Click to expand...

Yes, but as the sub FC is now receiving an any pointer, the code in the sub FC cannot use the UDT element names. You could refer to the elements using indirect addressing, but, if the UDT changes you will have to manually edit the block to change the offsets. The example I've shown in the attached library copies the udt to the temp area so you can process using the UDT names, the temp area is then copied back to the udt.
 

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