Digital Input Module With Interrupt Capability (Interrupt Di) - Siemens SIMATIC S5-115F User Manual

S5-115F Manual

10.9.8 Digital Input Module with Interrupt Capability (Interrupt DI)

The 434 interrupt DI is always a Type 3 I/O module
• Safety-related
• Two-Channel
• Non-intermittent.
This saves you the difficulty of having to verify the intermittent nature of the interrupt DI signals.
In addition, the frequency at which the signals change is monitored by the operating system.
Frequently changing signals are not tested.
Signal characteristics
The sensor signal must maintain a given state for at least 7 msec. for both signal levels. The interval
between two interrupts must be at least 30 msec.
Discrepancy time
You must configure the interrupt DI with a uniformly short discrepancy time.
Access
At the start of OB 2, you must read the 434 interrupt DI with a direct access so that the interrupt
register can be reset. Access to the interrupt registers in OB 1 and OB 13 is not permissible since the
OB 2 functions can be blocked by a random access before a pending OB 2 execution.
The status register can be read at any time and, like the interrupt register, it is not updated
cyclically.
The 115F operating system detects false interrupts. These result in the usual error response with
PLC STOP or in passivation of the relevant signal group.
Enable/disable initialization
Initialization is enabled/disabled automatically on restart according to the parameters assigned in
the configuration form. (Interrupts can only be triggered by negative edges.)
However, the user can still change the initialization enable/disable in the restart OBs (OB 21,
OB 22). You can either enable all or some interrupt DI bits assigned with COM 115F. Make sure
that you enable only those interrupt DI bits which you have configured with COM 115F.
In the case of write access to the interrupt DIs, the operating system checks that this rule is obeyed.
Edge initialization
The operating system initializes the interrupt DI bits used in the screen form for negative edge.
(Interrupts can only be triggered by negative edges.)
However, the user can still change the parameters in the restart OBs (OB 21, OB 22). In doing so,
the operating system checks that none of the enabled interrupt DI bits has been assigned a
positive edge. This ensures that, if the power supply to a sensor is cut off, it can still initiate the
safety function.
EWA 4NEB 811 6148-02
Rules Governing the Use of the S5-115F
10-25