Bilal390

1. Is there anyway to ignore output pin of an FC by not assigning address to it? I tried doing this with FB and it works fine. But in case of FC it gives me error message that address is not filled.

STEP7 Online Manual

You must always assign actual parameters to the formal parameters of an FC (for example, an actual parameter "I 3.6" to the formal parameter "Start").

Functions (FC)

Important Differences Between the Output Parameters of FCs and FBs

In function blocks (FB), a copy of the actual parameters in the instance DB is used when accessing the parameters. If an input parameter is not transferred or an output parameter is not write accessed when a FB is called, the older values still stored in the instance DB /Instance DB = memory of the FBs) will be used.

Functions (FC) have no memory. Contrary to FBs, the assignment of formal parameters to these FCs is therefore not optional, but rather essentially. FC parameters are accessed via addresses (pointers to targets across area boundaries). When an address of the data area (data block) or a local variable of the calling block is used as actual parameter, a copy of the actual parameter is saved temporarily to local data area of the calling block for the transfer of the parameter.

Bilal390

2. Can I negate the output/input pin of FB/FC?

Bilal390

3. Is it possible to add ladder logic elements (contact or coil) to an output pin of an FB/FC?

Thanks all for your kind help. These were things I could do with Unity Pro. Looks, I have to modify my Unity code to run on Siemens.

Thanks
Bilal