Toshiba T2N - Manual (Page 128)

3.User Program Running Control
User’s manual 115
The T2N can run several different types of program, main program, sub program
and interrupt program in parallel (this function is called the multitask function).
This function can be used to realize the optimal response time for each application.
The programs are classified into the following 3 types, there are a total of 7
programs.
•
Main program (one)
This program is executed every scan and forms the main part of the scan.
•
Sub program (one)
This program is called the sub program #1. When RUN starts up, it is executed
once only before the main program and after batch I/O processing and timer
update.
•
Interrupt program (five)
When the interrupt condition is set up, the interrupt program stops other operations
and is executed immediately. A total of 5 are provided : one program which
starts up at user specified intervals (fixed cycle timer interrupt program) and
4 programs which start up according to interrupt signals from I/O modules with
an interrupt function (I/O interrupt programs) (No.1 - No.4).
By using the timer interrupt, it results in taking place time critical control and
effective multitask control. By using I/O interrupts, I/O responses can take place
without affecting the scan cycle:
Sub program #1 and the interrupt program running method and the execution
conditions are explained in this section.
3.1
Program classification