Siemens SIMATIC NET CP 243-2 Manual page 53

Data Exchange in the STOP Mode of the S7-22x CPU
In the STOP mode, the S7-22x CPU sets bit PLC_RUN in the digital control area
to "0" automatically. As a result, the CP 243-2 outputs "0" data to all binary slaves.
Special Feature of Analog Slaves
If you use analog slaves complying with profile 7.3 or 7.4 the following points
apply:
In the input direction, the CP 243-2 sets the nibbles assigned to the slaves to
"0".
In the output direction, the CP 243-2 ignores the nibbles assigned to these
slaves.
Access to the analog data is described in Section 3.1.2.
SIMATIC NET CP 243-2 AS-i Master
C79000-G8976-C142/02
Access to the Data of the AS-i Slaves
3-5