Codesys: Instantiate a VAR_IN_OUT inside the FB?

[theColonel26]

Is it possible to instantiate a VAR_IN_OUT inside the FB?


The VAR_IN_OUT in question is function block that I call inside another function block, but I want to be able to access it outside of the parent FB.



I want to beable to do something like the following at a program level.

FB_A_Instance1.FB_Child.Setpoint := 123.56;

or am I just going to have to create an instance of FB_Child outside the FB_A and then pass it into FB_A?

 

[mk42]

Is it possible to instantiate a VAR_IN_OUT inside the FB?


The VAR_IN_OUT in question is function block that I call inside another function block, but I want to be able to access it outside of the parent FB.



I want to beable to do something like the following at a program level.

FB_A_Instance1.FB_Child.Setpoint := 123.56;

or am I just going to have to create an instance of FB_Child outside the FB_A and then pass it into FB_A?

In the Siemens world, we call that a multi-instance FB, where an instance of FB_Child is declared as a STAT of FB_A. Inside FB_a you would access it as #FB_Child_Instance.Setpoint, but you would also have to actually call FB_Child_Instance as an FB somewhere in FB_A.



I would assume Codesys allows that as well, but I have no experience there.

 

[AustralIan]

You can't reference FB_A_INST.x, where x is a var_in_out at all. So, the answer is no.
Passing it a child from outside is a normal way to do it.

 

[jagjag1]

Pointer

Myabe you can create an input as a pointer to lreal

VAR_INPUT
i_plrSetpoint : POINTER TO LREAL;
END_VAR


in the program you call it like this:
IF i_plrSetpoint^>100 THEN
;
END_IF

Hope this helps

Is it possible to instantiate a VAR_IN_OUT inside the FB?


The VAR_IN_OUT in question is function block that I call inside another function block, but I want to be able to access it outside of the parent FB.



I want to beable to do something like the following at a program level.

FB_A_Instance1.FB_Child.Setpoint := 123.56;

or am I just going to have to create an instance of FB_Child outside the FB_A and then pass it into FB_A?