SR

 Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Set dominant bistable.

Inputs

Input	Data Type	Range	Unit	Default	Description
SET1	BOOL				Condition for forcing to TRUE. Highest priority command.
RESET New start of the microprocessor.	BOOL				Condition for forcing to FALSE.

Outputs

Output	Data Type	Range	Unit	Description
Q	BOOL			Output to be forced.

Remarks

• The output is unchanged when both inputs are FALSE.
• When both inputs are TRUE, the output is forced to FALSE. (set dominant)

Truth Table

SET1	RESET	Q1 prev	Q1
0	0	0	0
0	0	1	1
0	1	0	0
0	1	1	0
1	0	0	1
1	0	1	1
1	1	0	1
1	1	1	1

FBD Language Example

FFLD Language Example

• The SET1 command is the rung.
  • The rung is the output.

IL Language Example

(* MySR is declared as an instance of SR function A function calculates a result according to the current value of its inputs. 
A function has no internal data and is not linked to declared instances. block *)
Op1: CAL MySR (SET1, RESET)
     FFLD  MySR.Q1
     ST  Q1

ST Language Example

(* MySR is declared as an instance of SR function block *)
MySR (SET1, RESET);
Q1 := MySR.Q1;

See Also

• R
• RS
• S