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The IEC Operators • 289

Arithmetic Operators

Note:

If you define functions in your project with the names CheckDivByte,

CheckDivWord, CheckDivDWord and CheckDivReal, you can use them to check the value of the divisor if you use the operator DIV, for example to avoid a division by 0. The functions must have the above listed names. See in the following an example for the implementation of function CheckDivReal:

Operator DIV uses the output of function CheckDivReal as divisor. In a program like shown in the following example this avoids a division by 0, the divisor (d) is set from 0 to 1. So the result of the division is 799.

12.2.5MOD

Modulo Division of one variable by another of the types: BYTE, WORD, DWORD, SINT, USINT, INT, UINT, DINT, UDINT. The result of this function will be the remainder of the division. This result will be a whole number.

WAGO-I/O-SYSTEM 759 WAGO-I/O-PRO 32

290 • The IEC Operators

Bitstring Operators

Example in IL:

Example in ST:

var1 := 9 MOD 2;

Example in FBD:

12.2.6INDEXOF

Perform this function to find the internal index for a POU.

Example in ST:

var1 := INDEXOF(POU2);

12.2.7SIZEOF

Perform this function to determine the number of bytes required by the given data type.

Example in IL:

arr1:ARRAY[0..4] OF INT;

Var1 INT

LD arr1

SIZEOF

Example in ST:

var1 := SIZEOF(arr1);

12.3 Bitstring Operators

12.3.1AND

Bitwise AND of bit operands. The operands should be of the type BOOL, BYTE, WORD or DWORD.

WAGO-I/O-SYSTEM 759 WAGO-I/O-PRO 32

Example in IL:

Example in ST:

var1 := 2#1001_0011 AND 2#1000_1010

Example in FBD:

Note:

If you have a program step in the SFC like the following

and if you use 68xxxor C-code generators, please note the following: The allocation of the value of the second input variable at the AND operator module to variable z will not be executed ! This is due to the optmized processing in the SFC in case of value FALSE at the input variable.

12.3.2OR

Bitwise OR of bit operands. The operands should be of the type BOOL,

BYTE, WORD or DWORD.

Example in IL:

var1 :BYTE;

Example in ST:

Var1 := 2#1001_0011 OR 2#1000_1010

Example in FBD:

WAGO-I/O-SYSTEM 759 WAGO-I/O-PRO 32

292 • The IEC Operators

Bitstring Operators

Note:

If you have a program step in the SFC like the following

and if you use 68xxxor C-code generators, please note the following: The allocation of the value of the second input variable at the AND operator module to variable z will not be executed ! This is due to the optmized processing in the SFC in case of value FALSE at the input variable.

12.3.3XOR

Bitwise XOR of bit operands. The operands should be of the type BOOL, BYTE, WORD or DWORD.

Example in IL:

Var1 :BYTE;

Example in ST:

Var1 := 2#1001_0011 XOR 2#1000_1010

Example in FBD:

12.3.4NOT

Bitwise NOT of a bit operand. The operand should be of the type BOOL, BYTE, WORD or DWORD.

Example in IL:

Var1 :BYTE;

LD 2#1001_0011

NOT

WAGO-I/O-SYSTEM 759 WAGO-I/O-PRO 32

Example in ST:

Var1 := NOT 2#1001_0011

Example in FBD:

12.4 Bit-Shift Operators

Note:

The code generator for the Infineon C16x target system carries out bit-shift calculating operations with modulo 16.

12.4.1SHL

Bitwise left-shift of an operand : erg:= SHL (in, n)

The input variables erg, in and n should be of the type BYTE, WORD, or DWORD. in will be shifted to the left by n bits and filled with zeros on the right.

Note:

Please note, that the amount of bits, which is regarded for the arithmetic operation, is pretended by the data type of the input variable !. If the input variable is a constant the smallest possible data type is regarded. The data type of the output variable has no effect at all on the arithmetic operation.

See in the following example in hexadecimal notation that you get different results for erg_byte and erg_word depending on the data type of the input variable (BYTE or WORD), although the values of the input variables in_byte and in_word are the same.

Example in ST:

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