7.1.2 RS

Function

RS is called reset priority standard bistable element, i.e. reset priority

LD graphics

Parameter description

Interface variables	Declaration	Data type	Description
S	Var_Input	BOOL	Enable set
R1	Var_Input	BOOL	Enable reset
Q1	Var_Output	BOOL	Operand signal status

Corresponding syntax

• Q1 = NOT R1 AND(Q1 OR S)
• When the S and R1 signals are both TRUE, the operand signal status is reset to "0";
• When the S signal is TRUE and the R1 signal is FALSE, the operand status is set to "1";
• When the S and R1 signals are both FALSE, the operand signal state remains unchanged.
• When the S signal is FALSE and the R1 signal is TRUE, the operand signal bit status is reset to "0"

warning

Function block usage requires global declaration of an instance

Example

• LD example is shown in the following animation:

• ST example is shown in the following code:

RS_1(S:=IN1,R1:=IN2,Q1=>OUT);
IF OUT THEN
    iVar:=1;
    ELSE
        iVar:=0;
END_IF;