Basic Characteristics RAPID

Program execution
Limitations
Interrupt Data type: intnum
The interrupt identity. This should have previously been connected to a trap routine
by means of the instruction CONNECT.
When the signal assumes the specified value, a call is made to the corresponding trap
routine. When this has been executed, program execution continues from where the
interrupt occurred.
If the signal changes to the specified value before the interrupt is ordered, no interrupt
occurs (see Figure 1).
:
1
Signal level
0
Interrupt ordered
Interrupt ordered
1
Signal level
0
Figure 1 Interrupts from a digital output signal at signal level 1.
The same variable for interrupt identity cannot be used more than once, without first
deleting it. Interrupts should therefore be handled as shown in one of the alternatives
below.
PROC main ( )
VAR intnum sig1int;
CONNECT sig1int WITH iroutine1;
ISignalDO do1, 1, sig1int;
WHILE TRUE DO
:
:
ENDWHILE
ENDPROC
Interrupt occurs
Interrupt occurs
All activation of interrupts is done at the beginning of the program. These instructions
are then kept outside the main flow of the program.
8-ISignalDO-2 RAPID Reference Manual