Chapter 8 Logic Instructions
8.3.5 SEMA
FB/FC
Explanation
FB
SEMA is used for giving priority to CLAIM. (The output will be valid in the
second period.)
DVP15MC11T
Parameters
Meaning
Description Valid range
CLAIM
Set signal TRUE or FALSE
RELEASE
Reset signal TRUE or FALSE
Q
Output Output signal TRUE or FALSE
Boolean
Bit string Integer
Real
number
Time, date
String
BOOL
WORD
DWORD
USINT
UINT
UDINT
ULINT
SINT
INT
DINT
LINT
REAL
LREAL
TIME
DATE
TOD
DT
STRING
CLAIM
●
RELEASE
●
Q
●
Note:
The symbol ● indicates that the parameter is allowed to connect to the variable or constant of the data type.
Function Explanation
When CLAIM of SEMA is TRUE, Q is TRUE. When RELEASE is TRUE, Q is FALSE. When CLAIM and
RELEASE are both TRUE, Q is TRUE.
Precautions for Correct Use
When CLAIM is TRUE, Q will be TRUE in the second period.
Programming Example
The variable table and program
Variable name Data type Initial value
SEMA
EN ENO
CLAIM
Q
SEMA_insta nce
RELEASE
8-15