4.1 User Program Types and Execution Timing
4.1.1 Ladder Programs
4-11
4
Creating User Programs
Functions
Functions are executed when they are called from a parent, child, or grandchild drawing with
the FUNC instruction.
Functions can be freely called from any drawing. The same function can be called simultane-
ously from different types of drawings or different levels of drawings. You can also call functions
from other functions that you have created.
The use of functions provides the following merits:
•
Easy user program modularization
•
Easy user program creation and maintenance
You can use standard functions that are provided by the system, and you can define user func-
tions.
Standard System Functions
The following functions for communications and other purposes are provided as standard func-
tions in the system. You cannot change the system functions.
User Functions
You can freely program the body of a user function and program the user function definitions.
The maximum number of user functions is 2,000 drawings.
Symbol
Function
COUNTER
Counter
FINFOUT
First-in First-out
TRACE
Trace
DTRC-RD
Read Data Trace
MSG-SND
Send Message
MSG-SNDE
Send Message Extended
MSG-RCV
Receive Message
MSG-RCVE
Receive Message Extended
MOTREG-W
Write Motion Register
MOTREG-R
Read Motion Register