This bistable function block realizes a prior reset of the output Q1. If the input SET = TRUE, the output Q1 is set. Q1 remains set even if SET becomes FALSE. Q1 is reset, if RESET1 = TRUE. If SET and RESET1 are TRUE, Q1 is set by RESET1 to FALSE. If the function block is called for the first time, Q1 is FALSE.
The function block is available as standard function block RS and safety-related function block RS_S.
RS
|
Parameter |
Data types |
Description |
|
SET |
BOOL |
If TRUE, Q1 is set |
|
RESET1 |
BOOL |
If TRUE, Q1 is reset dominant |
|
Q1 |
BOOL |
Output |
RS_S
|
Parameter |
Data types |
Description |
|
SET |
SAFEBOOL |
If TRUE, Q1 is set |
|
RESET1 |
SAFEBOOL |
If TRUE, Q1 is reset dominant |
|
Q1 |
SAFEBOOL |
Output |
NOTE:
Function blocks have to be instantiated. Like variables, instances have to be declared before they can be inserted in a code body. Instances must be unique within the POU. In the following example, the instance name 'RS_S_1' is used for the RS_S FB.
Example for a safety-related function block declaration RS_S
Variables declarations in this example
NOTE:
If you want to use the standard function block RS in your code worksheet, you have to select the data type 'RS' for the function block instance in the local variables worksheet. Accordingly, the data type 'BOOL' must be used instead of 'SAFEBOOL'.
