38
Function Blocks
Section 1-5
1-5
Function Blocks
In the SYSMAC CP Series, function blocks can be used in programming just
as in the CS/CJ Series.
1-5-1
Overview of Function Blocks
A function block is a basic program element containing a standard processing
function that has been defined in advance. Once the function block has been
defined, the user just has to insert the function block in the program and set
the I/O in order to use the function.
As a standard processing function, a function block is not created with actual
physical addresses, but local variables. The user sets parameters (addresses
or values) in those variables to use the function block. The addresses used for
the variables themselves are automatically assigned by the system (CX-Pro-
grammer) each time they are placed in the program.
In particular, each function block is saved by the CX-Programmer as an indi-
vidual file that can be reused with programs for other PLCs. This makes it pos-
sible to create a library of standard processing functions.
1-5-2
Advantages of Function Blocks
Function blocks allow complex programming units to be reused easily. Once
standard program sections have been created as function blocks and saved in
files, they can be reused just by placing a function block in a program and set-
ting the parameters for the function block's I/O. Reusing standardized function
blocks reduces the time required for programming/debugging, reduces coding
errors, and makes programs easier to understand.
Structured
Programming
Structured programs created with function blocks have better design quality
and required less development time.
cc
aa
bb
#0000
MOV
dd
Standard program
section written
with variables
Function block A
Define in advance.
Insert in program.
Save function
block as file.
Library
Function
block A
Reuse
To another PLC program
Program 1
Copy of function block A
Input
Variable
Variable
Output
Setting
Setting
Copy of function block A
Input
Variable
Variable
Output
Program 2
Copy of function block A
Variable
Output
Summary of Contents for CP1H-CPU - 05-2006
Page 2: ...CP1H X40D CP1H XA40D CP1H Y20DT D CP1H CPU Unit Operation Manual Revised May 2006...
Page 3: ...iv...
Page 11: ...xii TABLE OF CONTENTS...
Page 15: ...xvi...
Page 19: ...xx...
Page 31: ...xxxii Conformance to EC Directives 6...
Page 71: ...40 Function Blocks Section 1 5...
Page 133: ...102 Computing the Cycle Time Section 2 7...
Page 169: ...138 CPM1A Expansion I O Unit Wiring Section 3 6...
Page 411: ...380 Clock Section 6 8...
Page 519: ...488 Replacing User serviceable Parts Section 10 2...
Page 527: ...496 Standard Models Appendix A...
Page 535: ...504 Dimensions Diagrams Appendix B...
Page 628: ...597 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Page 629: ...598 Connections to Serial Communications Option Boards Appendix F...
Page 659: ...628 PLC Setup Appendix G...
Page 665: ...634 Index work words 159 write protection 370...
Page 667: ...636 Revision History...