Siemens Simatic S7-400 - Manual (Page 546)

Interface Submodules
13-50
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Cyclic Conversion of the ADC Channels
Below are listed the steps required for cyclic conversion of the ADC channels:
1. Set the AC bit in control register 1 to “1” (offset address “08
H
”).
2. Wait for interrupt.
3. Read the values at the relevant address (offset addresses “00
H
” to “06
H
”).
4. Acknowledge the interrupt by writing to the offset address “0E
H
”, data bits 0 to
15 are irrelevant here.