Addressing
S5-115F Manual
5.5
Process Interrupt Generation with the 6ES5 434-7LA12 Digital Input
Module
Interrupt generation can be programmed on the 6ES5 434-7LA12 input module. In the S5-115F
there are only two-channel, i.e. safety-related, interrupt inputs. There is a limit of one module per
subunit. This module must be plugged into the central controller.
5.5.1
Functional Description
Process interrupts trigger two different responses in the interrupt module:
•
They change register contents
- The interrupt register stores configured edge changes with a ”1” (LPY with module address
+ 1)
- The status register flags the current signal status (LPB with module address).
Register contents are not transferred cyclically to the PII. They can only be read in by direct
access. The interrupt register is automatically deleted when read.
•
An LED lights up on the module and a relay picks up. This indication is also retained even after
power failure, and can only be reset by pressing the 24 V Reset input.
5.5.2
Initialization
The CPU 942-7UF12 operating system automatically programs the interrupt DI bits used in the
screen form for negative-going edge.
However, the user can change the parameters in the restart OBs (OB 21, OB 22). The operating
system monitors that none of the enabled interrupt DI bits is assigned a positive-going edge
during edge initialization. This ensures that a sensor in the process of losing voltage can initiate
the safety function.
The following must be programmed in the OB 21 and OB 22 restart blocks
•
Those inputs which are to trigger an interrupt
•
Whether the interrupt is to be triggered by a rising or falling edge (in the case of the safety-
related S5-115F, interrupts can only be triggered by a falling edge).
This information is defined in two bytes, which are transferred to the module by the program in
OB 21 or OB 22.
5-12
EWA 4NEB 811 6148-02
