Hi,

I have programmed a up/down counter (UDC) module on CoDeSys.

My problem is : I would like to use the same function_block for all my UDC modules but the addresses of the variables (such as "AT %QX0.0") change from one module to another. All the modules are UDC-type but %QX0.0 become %QX2.0 for module 2 and so on...

Is it possible to automatically allocate the addresse of the variables so I can use the same function_block for the different modules ?

Thank you for any response.

Hi,
just do not use absolute addresses inside the UDC function block

FUNCTION_BLOCK UDC
VAR_OUTPUT
  qxSomeOutput : BOOL;  (* that's all you need *)
END_VAR

To get the outputs of a module instance, use the instance identifier :

VAR
  AnUDCInstance : UDC;
  AnUDCOutput   : BOOL;
END_VAR
(* --- *)
AnUDCOutput := AnUDCInstance.qxSomeOutput;

With CoDeSys, you need absolute addresses für physical inputs / outputs only. All other data the compiler is able to allocate dynamically.

Have success
Rolf

.

Ok thank you but how do I link "AnUDCInstance.qxSomeOutput" to a physical address after that ?

I mean I know that I could write "%QX1.0:=AnUDCInstance.qxSomeOutput" so the physical Ouput take the value of my variable but how can I do this automatically or with some kind of function ?

Because to every I/O of the function block it exists the I/O of the Wago module but with a different address for every module...
Hope I'm clear enough...

Benoit.

Hi,

VAR
  AnUDCInstance : UDC;
  AnUDCOutput AT %QX0.0 : BOOL;  (* This assigns a physical address *)
END_VAR
(* --- *)
AnUDCOutput := AnUDCInstance.qxSomeOutput;  (* This brings the UDC output to the absolutely addressed target *)

Rolf

ok, nice!

May I write directly :

AnUDCInstance.qxSomeOutput AT QX0.0

Or do I have to assign a physical address to a variable and then put the data of my function block in the variable like the way you did ?

Thankt you!

Hello Benoit,
sorry for the late reply. Had been off for a few days.
```

AnUDCInstance.qxSomeOutput AT QX0.0

``` probably willl not work. I can't imagine, how the compiler could assign an absolute address to just a little part of a function block.
The safe way is to have just variables with certain addresses, to which you assign the output var of the FB instance, as I suggested it in one of my posts.
Rolf