Basic Concepts; Programs And Tasks - Omron CJ - PROGRAMMING MANUAL 08-2008 Programming Manual

Basic Concepts

2-1

Basic Concepts

2-1-1

Programs and Tasks

22
CS/CJ-series PLCs execute ladder-diagram programs contained in tasks. The
ladder-diagram program in each task ends with an END(001) instruction just
as with conventional PLCs.
Tasks are used to determine the order for executing the ladder-diagram pro-
grams, as well as the conditions for executing interrupts.
Allocated
Cyclic
Interrupt condition met.
task 1
Interrupt
task
Cyclic
task n
Allocated
I/O refresh
This section describes the basic concepts required to write CS/CJ-series pro-
grams. See SECTION 4 Tasks for more information on tasks and their rela-
tionship to ladder-diagram programs.
Note Tasks and Programming Devices
Tasks are handled as described below on the Programming Devices. Refer to
4-4 Programming Device Operations for Tasks and to the CS/CJ-series Pro-
gramming Consoles Operation Manual (W341) and CX-Programmer Opera-
tion Manual for more details.
CX-Programmer
The CX-Programmer is used to designate task types and task numbers as
attributes for individual programs.
Programming Console
Programs are accessed and edited on a Programming Console by specifying
CT00 to CT 31 for cyclic tasks and IT00 to IT255 for interrupt tasks. When the
memory clear operation is performed with a Programming Console, only
cyclic task 0 (CT00) can be written in a new program. Use CX-Programmer to
create cyclic tasks 1 through 31 (CT01 through CT31).
Program A
Program B
Allocated
Program C
Section 2-1
Each ladder-diagram
program ends with an
END(001) instruction.