User guide

A–B

Chapter

31–1

Understanding I/O Interrupts – SLC 5/02

Processor Only

This chapter applies to the SLC 5/02 processor only. It covers the following

topics:

• I/O interrupt operation

• I/O interrupt parameters

• IID and IIE instructions

• RPI instruction

• INT instruction

The I/O event-driven interrupt function can be used with the SLC 5/02

processor only. This function allows a specialty I/O module to interrupt the

normal processor operating cycle in order to scan a specified subroutine file.

Interrupt operation for a specific module is described in the user’s manual for

the module.

I/O event-driven interrupts cannot be accomplished using standard discrete

I/O modules.

Basic Programming Procedure for the I/O Interrupt Function

• Specialty I/O modules which create interrupts should be configured in the

lowest numbered I/O slots. When you are configuring the specialty I/O

module slot with the HHT, select the ADV_SET and INT_SBR function

keys and program the “ISR” (interrupt subroutine) program file number

(range 3–255) that you want the I/O module to execute.

Configuring I/O is discussed in chapter 6.

• Create the subroutine file that you have specified in the I/O module slot

configuration.

Creating a subroutine file is discussed in chapter 4.

I/O Overview