2-28
Section 2 Programming Languages
2-3-2 Function block summary
Function blocks are supported by the IL, ST, LD, and FBD languages. The operation of a function block remains the same for
these languages.
The notational conventions used in the function block summary charts are almost the same as those which are used in the
function summary charts except the following:
•
There are instructions that have two or more output terminals.
•
Edge inputs can be used.
• The number of input terminals is fixed (and cannot be extended).
• Both input and output terminals have a predefined name (parameter name).
• There are instructions that have the IN_OUT parameter.
(1) Symbols used in the function block summary
Instruction symbol
No. of steps Page
Name
12
12
FEH200
2-4-3
FB name
Instance name (Note 2)
Output data type
Input data type
Up counter CTU
Down counter CTD
Rising edge input
BOOL
INT
CU
RESET
PV
BOOL
BOOL
INT
Q
CV
CTU
CTU_1
BOOL
INT
CD
LOAD
PV
BOOL
BOOL
INT
Q
CV
CTD
CTD_1
Notes:
1) The number of steps depends on the operands used. Consequently, the number of steps of array variables will be greater
than that of scalar variables.
2) Every FB uses its own memory area called an instance memory in order to operate. An FB number called an instance name
is assigned to each FB. This means that the FBs with the same instance name assigned share the same instance area. Pay
attention to any duplicate instance name when an FB is used.
3) The FBs provided in the MICREX-SX Series (IEC standard FBs and original FBs) are called “system FBs,” and the FBs
created by the user are called “user FBs.” The system FBs use the system FB instance memory and user FBs use the user
FB instance memory.
4) The standard memory area not specified in the AT statement is used. (2-word/FB instance).
5) D300win does not check the data type of the terminal associated with functions ANY or ARRAY_OF** or ARRAY_OF_*X.
Use the data types appropriate for function blocks, following their detailed explanations.
