The value of an operand is loaded into the accumulator using LD. The size of the accumulator adapts automatically to the data type of the operand. This also applies to the derived data types.

Example: In this example the value of A is loaded into the accumulator, the value of B then added and the result saved in E.

LD A

ADD B

ST E

The current value of the accumulator is stored in the operand using ST. The data type of the operand must be the same as the "data type" of the accumulator.

Example: In this example the value of A is loaded into the accumulator, the value of B then added and the result saved in E.

LD A

ADD B

ST E

The "old" result is used in subsequent calculations, depending on whether or not an LD follows an ST.

Example: In this example the value of A is loaded into the accumulator, the value of B then added and the result saved in E. The value of B is then subtracted from the value of E (current accumulator content) and the result saved in C.

LD A

ADD B

ST E

SUB 3

ST C

S sets the operand to "1" when the current content of the accumulator is a Boolean 1.

Example: In this example the value of A is loaded to the accumulator. If the content of the accumulator (value of A) is 1, then OUT is set to 1.

LD A

S OUT

Usually this operator is used together with the reset operator R as a pair.

Example: This example shows a RS flip-flop (reset dominant) that is controlled through the two Boolean variables A and C.

LD A

S OUT

LD C

R OUT

R sets the operand to "0" when the current content of the accumulator is a Boolean 1.

Example: In this example the value of A is loaded to the accumulator. If the content of the accumulator (value of A) is 1, then OUT is set to 0.

LD A

R OUT

Usually this operator is used together with the set operator S as a pair.

Example: This example shows a SR flip-flop (set dominant) that is controlled through the two Boolean variables A and C.

LD A

R OUT

LD C

S OUT

The AND operator makes a logical AND link between the accumulator content and the operand.

In the case of BYTE, WORD and DWORD data types, the link is made bit by bit.

Example: In the example D is 1 if A, B and C are 1.

LD A

AND B

AND C

ST D

The OR operator makes a logical OR link between the accumulator content and the operand.

In the case of BYTE, WORD and DWORD data types, the link is made bit by bit.

Example: In the example D is 1 if A or B are 1 and C is 1.

LD A

OR B

OR C

ST D

The XOR operator makes a logical exclusive OR link between the accumulator content and the operand.

If more than two operands are linked, the result with an uneven number of 1-states is 1, and is 0 with an even number of 1-states.

In the case of BYTE, WORD and DWORD data types, the link is made bit by bit.

Example: In the example D is 1 if A or B is 1. If A and B have the same status (both 0 or 1), D is 0.

LD A

XOR B

ST D

If more than two operands are linked, the result with an uneven number of 1-states is 1, and is 0 with an even number of 1-states.

Example: In the example F is 1 if 1 or 3 operands are 1. F is 0 if 0, 2 or 4 operands are 1.

LD A

XOR B

XOR C

XOR D

XOR E

ST F

The accumulator content is inverted bit by bit with NOT.

Example: In the example B is 1 if A is 0 and B is 0 if A is 1.

LD A

NOT

ST B

With ADD the value of the operand is added to the value of the accumulator contents.

Example: The example corresponds to the formula D = A + B + C

LD A

ADD B

ADD C

ST D

With SUB the value of the operand is subtracted from the accumulator content.

Example: The example corresponds to the formula D = A - B - C

LD A

SUB B

SUB C

ST D

The MUL operator multiplies the content of the accumulator by the value of the operand.

Example: The example corresponds to the formula D = A * B * C

LD A

MUL B

MUL C

ST D

Note: The MULTIME function in the obsolete library is available for multiplications involving the data type Time.

The DIV operator divides the contents of the accumulator by the value of the operand.

Example: The example corresponds to the formula D = A / B / C

LD A

DIV B

DIV C

ST D

Note: The DIVTIME function in the obsolete library is available for divisions involving the data type Time.

The MOD operator divides the value of the first operand by the value of the second and returns the remainder (Modulo) as the result.

Example: In this example

• C is 1 if A is 7 and B is 2

• C is 1 if A is 7 and B is -2

• C is -1 if A is -7 and B is 2

• C is -1 if A is -7 and B is -2

LD A

MOD B

ST C

The GT operator compares the contents of the accumulator with the contents of the operand. If the contents of the accumulator are greater than the contents of the operands, the result is a Boolean 1. If the contents of the accumulator are less than/equal to contents of the operands, the result is a Boolean 0.

Example: In the example the value of D is 1 if A is greater than 10, otherwise the value of D is 0.

LD A

GT 10

ST D

The GE operator compares the contents of the accumulator with the contents of the operand. If the contents of the accumulator are greater than/equal to the contents of the operands, the result is a Boolean 1. If the contents of the accumulator are less than the contents of the operands, the result is a Boolean 0.

Example: In the example the value of D is 1 if A is greater than or equal to 10, otherwise the value of D is 0.

LD A

GE 10

ST D

The EQ operator compares the contents of the accumulator with the contents of the operand. If the contents of the accumulator is equal to the contents of the operands, the result is a Boolean 1. If the contents of the accumulator are not equal to the contents of the operands, the result is a Boolean 0.

Example: In the example the value of D is 1 if A is equal to 10, otherwise the value of D is 0.

LD A

EQ 10

ST D

The NE operator compares the contents of the accumulator with the contents of the operand. If the contents of the accumulator are not equal to the contents of the operands, the result is a Boolean 1. If the contents of the accumulator are equal to the contents of the operands, the result is a Boolean 0.

Example: In the example the value of D is 1 if A is not equal to 10, otherwise the value of D is 0.

LD A

NE 10

ST D

The LE operator compares the contents of the accumulator with the contents of the operand. If the contents of the accumulator are less than/equal to the contents of the operands, the result is a Boolean 1. If the contents of the accumulator are greater than the contents of the operands, the result is a Boolean 0.

Example: In the example the value of D is 1 if A is smaller than or equal to 10, otherwise the value of D is 0.

LD A

LE 10

ST D

The LT operator compares the contents of the accumulator with the contents of the operand. If the contents of the accumulator is less than the contents of the operands, the result is a Boolean 1. If the contents of the accumulator is greater than/equal to contents of the operands, the result is a Boolean 0.

Example: In the example the value of D is 1 if A is smaller than 10, otherwise the value of D is 0.

LD A

LT 10

ST D

A function block, DFB or subprogram is called up conditionally or unconditionally with CAL.

see also Calling Elementary Function Blocks and Derived Function Blocks and Subroutine Call

A function is performed by specifying the name of the function.

see also Calling Elementary Functions

A procedure is performed by specifying the name of the procedure.

see also Calling Procedures

With JMP a jump to the label can be conditional or unconditional.

see also Labels and Jumps

RETURN operators can be used in DFBs (derived function blocks) and in SRs (subroutines).

RETURN operators can not be used in the main program.

• In a DFB, a RETURN operator forces the return to the program which called the DFB.

  • The rest of the DFB section containing the RETURN operator is not executed.

  • The next sections of the DFB are not executed.

  The program which called the DFB will be executed after return from the DFB.

  If the DFB is called by another DFB, the calling DFB will be executed after return.

• In a SR, a RETURN operator forces the return to the program which called the SR.

  • The rest of the SR containing the RETURN operator is not executed.

  The program which called the SR will be executed after return from the SR.

A right bracket ) starts the processing of the deferred operator. The number of right bracket operations must be equal to the number of left bracket modifiers. Brackets can be nested.

Example: In the example E is 1 if C and/or D is 1 and A and B are 1.

LD A

AND B

AND( C

OR D

)

ST E