Siemens SIMATIC S7-1500 Manual page 82

You can activate any combination of events to trigger hardware interrupts.
You can obtain detailed information on the event in the hardware interrupt organization block
with instruction "RALRM" (Read additional alarm information) and in the information system
of STEP 7.
Which channel of the module and which event has triggered the hardware interrupt is
entered in the start information of the organization block. The following figure shows the
assignment to the bits of the local data double word 8.
Figure 5-2 Start information of the organization block
Technology module TM PosInput 2 (6ES7551-1AB00-0AB0)
Manual, 06/2018, A5E03982218-AB
Interrupts/diagnostic messages
5.3 Hardware interrupts
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