Hi,

I have

buffer: ARRAY [1..1024] OF BYTE;

and need bit access in to small part this array, I created this:

Jednotky : POINTER TO  ARRAY[1..20] OF BOOL;
jednotky   : ARRAY[1..20] OF BOOL;
pJednotky := ADR(buffer);
Jednotky := pJednotky^;

At view array jednotky :

Jdnotka[1] : BOOL := INVALID 16#F0

Jdnotka[2] : BOOL := INVALID 16#F3

Jdnotka[3] : BOOL := false;

It's number contains in buffer. But i Think that CoDeSys partitions on 20 singl bits. Way? How to repair?

Hi Paul,

Thats a quite normal behavior in CoDeSys. A boolean needs a byte of memory space so your pointer points to the 20 first bytes. Whats about typing ```

buffer[1].0

```? This code accesses the first bit of first index.

regards

Ralph

But I need access over some variable. Buffer[0].somevar is not possible.

What specifically are you trying to accomplish? Maybe there is a better way of doing it. Also CoDeSys is not case sensitive, it appears to me that you have the same variable defined twice.

True you can only reference a bit by a constant not ba a variable

a simple trick is to do the following:

tmp := shr(INbyte, N);

Bit := tmp.0;

in the open source library OSCAT.LIB you can find functions like this to get a bit referenced by a variable.

w www.oscat.de w