TwinCat structure of bools from status int

I have an INT variable containing the value of a status word. I have also created a structure of 16 BOOL. Instead of having to manually set each structure element to my INT.bit, I am attempting to use the trick of addressing two variables at the same address.

Example:
ABB_StatWord_Intermediate AT %MB1000: INT;
ABB_Status AT %MB1000: ST_ABB_STATUS_WORD;


My Structure looks like:
TYPE ST_ABB_STATUS_WORD :
STRUCT
Ready: BOOL;
SwitchedOn: BOOL;
OpEnabled: BOOL;
Fault: BOOL;
VoltEnabled: BOOL;
QuickStopActive: BOOL;
Bit6: BOOL;
Warning: BOOL;
Bit8: BOOL;
Bit9: BOOL;
Bit10: BOOL;
Bit11: BOOL;
Bit12: BOOL;
Bit13: BOOL;
Bit14: BOOL;
Bit15: BOOL;

END_STRUCT
END_TYPE


This is not working, as the first two structure elements bascially becom INVALID.

What am I missing?

TwinCAT does not "pack" Booleans of a structure. Each Boolean of the structure takes 1 byte in memory.

You would probably have to create a function that transfers each bit of the word into the individual elements of the structure.

Does this Beckhoff Infosys article help in any way? https://infosys.beckhoff.com/englis...1033/tc3_plc_intro/18014401038825355.html&id=


Does using the BIT type in your structure vs. BOOL change anything? I don't have T/C open at the moment so I can't test it.



Pi

I have been in this situation before and if memory serves me I think that changing the BOOLs to BITs in your structure will fix the problem as Pireciter suggested.

At the end of the day, I am only interested in 6 or so of the bits. I just did it the normal way:
ABB_Status.Ready := ABB_StatWord_From_OverEcat.0;
ABB_Status.SwitchedOn:= ABB_StatWord_From_OverEcat.1;
etc.

I will play with some of this info at home.

Thanks

Are you using TwinCAT 2 or 3?

TwinCat2

It looks like TwinCat2 does not support the BIT.


So I found a work around that seems to work very well.
I created an instance of the structure and a 16 element array of BOOL addressed at the same location:
VAR_GLOBAL
MyInt : UINT;
MyBoolArray AT %MW100: ARRAY [0..15] OF BOOL;
MyStruct AT %MW100: ST_ABB_STATUSWORD;
END_VAR

My Test structure definition is:
TYPE ST_ABB_STATUSWORD :
STRUCT
Bool0 : BOOL ;
Bool1 : BOOL ;
Bool2 : BOOL ;
Bool3 : BOOL ;
Bool4 : BOOL ;
Bool5 : BOOL ;
Bool6 : BOOL ;
Bool7 : BOOL ;
Bool8 : BOOL ;
Bool9 : BOOL ;
Bool10 : BOOL ;
Bool11 : BOOL ;
Bool12 : BOOL ;
Bool13 : BOOL ;
Bool14 : BOOL ;
Bool15 : BOOL ;

END_STRUCT
END_TYPE


I then created a simple FB:

FUNCTION_BLOCK FB_IntToBoolArray
VAR_INPUT
InputInt : INT;

END_VAR
VAR_OUTPUT
OutputBoolArr: ARRAY [0..15] OF BOOL;

END_VAR
VAR
END_VAR


OutputBoolArr[0] := InputInt.0 ;
OutputBoolArr[1] := InputInt.1 ;
OutputBoolArr[2] := InputInt.2 ;
OutputBoolArr[3] := InputInt.3 ;
OutputBoolArr[4] := InputInt.4 ;
OutputBoolArr[5] := InputInt.5 ;
OutputBoolArr[6] := InputInt.6 ;
OutputBoolArr[7] := InputInt.7 ;
OutputBoolArr[8] := InputInt.8 ;
OutputBoolArr[9] := InputInt.9 ;
OutputBoolArr[10] := InputInt.10 ;
OutputBoolArr[11] := InputInt.11 ;
OutputBoolArr[12] := InputInt.12 ;
OutputBoolArr[13] := InputInt.13 ;
OutputBoolArr[14] := InputInt.14 ;
OutputBoolArr[15] := InputInt.15 ;

###############


This works very well. I did this on my home test/practice CX8090, I will implement it back into the project/system I was working on today.