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39
Function Blocks
Section 1-5
Easy-to-read “Block Box”
Design
The I/O operands are displayed as local variable names in the program, so
the program is like a “black box” when entering or reading the program and no
extra time is wasted trying to understand the internal algorithm.
Different Processes Easily
Created from a Single
Function Block
Many different processes can be created easily from a single function block by
using input variables for the parameters (such as timer SVs, control con-
stants, speed settings, and travel distances) in the standard process.
Reduced Coding Errors
Coding mistakes can be reduced, because blocks that have already been
debugged can be reused.
Data Protection
The local variables in the function block cannot be accessed directly from the
outside, so the data can be protected. (Data cannot be changed unintention-
ally.)
Improved Reusability
through Programming
with Variables
The function block's I/O is entered as local variables, so the data addresses in
the function block do not have to be changed as they do when copying and
reusing a program section.
Creating Libraries
Processes that are independent and reusable (such as processes for individ-
ual steps, machinery, equipment, or control systems) can be saved as func-
tion block definitions and converted to library functions.
The function blocks are created with local variable names that are not tied to
physical addresses, so new programs can be developed easily just by reading
the definitions from the file and placing them in a new program.
Nesting Multiple
Languages
Mathematical expressions can be entered in structured text (ST) language.
Nesting function blocks is supported for CX-Programmer Ver. 6.0 or higher.
For example, it is possible to express only special operations in ST language
within a function block in a ladder diagram.
For details on using function blocks, refer to the CX-Programmer Ver. 7.0
Operation Manual: Function Blocks (Cat. No. W447).
Function block (ladder language)
Call (Nesting)
Function block (ST language)
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...