IDEC SmartAXIS Touch FT1A Series, User Manual

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4 Special Functions
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SmartAXIS Touch User's Manual
4.13 Timer Interrupt
This section describes the timer interrupt that executes the interrupt program at a regular time interval.
The timer interrupt can only be used when ladder program is selected as the programming language.
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Feature Description
The timer interrupt is a function that executes a subroutine program with a predetermined label number as the
interrupt program at a regular time interval. The Function Area Settings dialog box is used to enable the timer
interrupt and to specify the interval, from 10 to 140 milliseconds, to execute the timer interrupt. When the timer
interrupt is enabled, the program execution jumps to the jump destination label number stored in special data register
D8036 repeatedly while the Touch is running.
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Disable and Enable Interrupts
The timer interrupt is normally enabled while the Touch is running, and can also be individually disabled using the DI
instruction or enabled using the EI instruction. When timer interrupt is enabled, Touch is turned on. When disabled,
Touch is turned off.
For details, refer to Chapter 16 "Interrupt Control Instructions" in "SmartAXIS Ladder Programming Manual".
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Notes for Using Timer Interrupt and Interrupt Inputs
• When using a timer interrupt or interrupt input, separate the interrupt program from the main program using the
END instruction at the end of the main program.
• When an interrupt program calls another subroutine, a maximum of 3 subroutine calls can be nested. If more than
3 calls are nested, a ladder program execution error occurs.
• The label numbers stored in data registers D8036 specify the interrupt programs for interrupt inputs I2, I3, I4, and
I5 and timer interrupt, respectively.
• If an interrupt is initiated while another interrupt program is executed, the subsequent interrupt program is
executed after the prior interrupt is completed. Multiple interrupt programs cannot be executed simultaneously.
• Make sure that the execution time of the interrupt program is shorter than interrupt intervals sufficiently.
• Interrupt programs cannot use some instructions. For details, refer to Chapter 12 “2.2 Instructions Reference” on
page 12-14.
D8036 Timer Interrupt Jump Destination Label No. R/W
A label is the starting address of the program branch to jump to, and it is specified by the LABEL instruction.