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Programming

BC8050 und BC8150 51Version: 3.0.0

Due to the fact that another variable type (INT) follows the first byte, in the BX/BCxx50 it was assigned the

next free even address. In order to achieve the same data structure on both systems, a dummy byte has to

be inserted in the PC project (see example2).

Example 2: A structure on the BX/BCxx50 and on the PC with the same memory allocation

Variable BX/BCxx50 memory PC memory (TwinCAT)

Byte %..B0 %..B0

Byte

(dummy)

%..B1 (not necessarily required, since the system

deals with this itself if the variable does not exist)

%..B1

INT (1) %..B2 %..B2

INT (2) %..B4 %..B4

Data structure

TypePB_Data

STRUCT

wVar_1:WORD;

iValue_1:INT;

iValue_2:INT;

iValue_3:INT;

END_STRUCT

END_TYPE

Creating a variable structure

VAR_Global

strData_OutAT%QB1000:PB_Data;(*PLCVariables*)

bInput_01AT%IX0.0:BOOL;(*Inputfromaterminal*)

END_VAR

Small programming example

strData_Out.wVar_1.0:=bInput_01;

Note

Do not use real values in a mixed data structure

A mixed data structure should not contain real values. If this is nevertheless the case, the

high and low words must be swapped in the BX/BCxx50 or in the TwinCAT master project.

It is better to use an array of Real values or to transfer the Real values individually.

Note

Larger fieldbus data blocks

You can transfer larger fieldbus data blocks, in order to have a reserve for your structure.

Disadvantage: These reserves are then transferred with each fieldbus telegram, resulting in

overload of the fieldbus communication.

Beckhoff BC8050 User Manual

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