Siemens SIMATIC S5 IP 281 Equipment Manual page 80

Interrupt Processing
Interrupt Processing
4.2
This type of interrupt acquisition uses special interrupt lines on the S5 backplane bus to feed the
interrupt signal to the central processing unit.
When selecting the slots, remember that interrupt lines are not available on
Slot selection
all slots (+ section 8.5 and equipment manual of the PLC).
Interrupt line One interrupt line on the module must be selected via DIL switch S2 to feed
the interrupts from the [P 281 to the central processing unit.
selection
S2
OFF:
ON:
The
switches must beset to OFF. All fou; switches must beset to OF
Several IP281 modules can reconnected to one interrupt line. The module
which triggered the interrupt is determined in your interrupt program by
reading the interrupt information registers on the modules.
One organization block of the interrupt processing is assigned to each inter-
rupt line. It is called when the corresponding interrupt line is activated.
When several interrupts are queued, they are processed in the order of their
priority (either set in data blockDXO(forS5–135U and S5– 155U) or start-
ing with the organization block with the lowest number).
4 – 2
IRA
No interrupt
Interrupt via the applicable line
switch for the selected interrurX line must be set to ON: all other
R 11192
-
F when the