Siemens SIMATIC S5-115U, User Manual, Page: 293 / 676

S5-115U Manual Interrupt Processing
The digital input/output module occupies
•
4 input bytes
and
• 4 output bytes
under a base address.
The input and output bytes are stored starting from the same base address.
You must set 32 channels for this module on the IM 306 interface module in the case of variable
slot addressing.
The addresses of the contiguous I/O bytes occupied by the 485-7 module are indicated below with
the addresses "x", "x + 1", "x + 2" and "x + 3"
9.4.2 Operating the Module with Alarm Processing
If you use the digital input/output module with alarm processing, you must set the mode selector
on the back of the module to "ALARM ON" (see Figure 9.2).
The module can be used in the "with alarm processing" mode in all central controllers
(CR 700-0/1/2/3) but not in the expansion units (ER 701-0/1/2/3).
When alarm processing is set, the digital input/output module gives you 4 input channels for
alarm processing (see Figure 9.3).
Process alarms are always initiated by a "0" to "1" transition at the alarm inputs.
In addition, in the case of process alarms at the input (x + 2).4, the signal states at inputs x.0 to x.3
are stored in the alarm register (see Figure 9.3).
The time at which inputs x.0 to x.3 are stored corresponds to the time of storing the alarm input in
the alarm register.
However, please note the different input delay times of the inputs:
-
alarm inputs: typ. 1.5 ms
- "normal" inputs: typ. 3 ms
If a change at one of the inputs x.0 to x.3 is also to be stored, allowance must be made for the
difference between the typical delay times of the inputs relative to the alarm input.
Reading the inputs
Input bytes x and x + 1 can always be read. These input bytes are accounted for in the process
image of the inputs (access with A I, L IB, L IW, L PB, L PW, ...).
Input byte x + 2 can always be read except during restart. This byte is not accounted for in the
process image of the inputs, i.e. input byte x + 2 must be accessed via direct I/O access (L PB).
EWA 4NEB 811 6130-02b
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