Hello,

How can I pass a variable value from a FB_A to FB_B.

FB_A

var_a1 := 2;

FB_B

var_b1 := var_a1; ??

Is it possible? If yes, how?
Thanks

There are several ways to do so. The easiest way would be to declare var_a1 as output of FB_A:

PROGRAM PLC_PRG
VAR
InstanceA:FB_A;
InstanceB:FB_B;
END_VAR
InstanceA();
InstanceB();
...
FUNCTION_BLOCK FB_A
VAR_OUTPUT
var_a1:INT;
END_VAR
var_a1 := 2;
FUNCTION_BLOCK FB_B
VAR
var_b1:INT;
END_VAR
var_b1 := InstanceA.var_a1;

Hello,
thanks for your answer. I tried already but is not working. I made a screenshot.

It works well on my project...
Please try the attached Project...

Now I see: you have two different instances of the same FB_A.
Replace the call in FB_B by this:

var_b1 := InstanceA.var_a1;

FB_Vars.project [133.29 KiB]

I see! Now is working properly.

The problem was that the program (PRG) was missing before the instance.

 var_b1 := PRG_COM.InstanceA.var_a1;

Thanks