Siemens SIDOOR AT40 System Manual page 100

Controllers
6.3 Safety concept ATD4xxW
Antivalent connection of an antivalent sensor to two channels
A 2-channel sensor is required for the signal (1oo2 evaluation)
Image 6-10
Image 6-11
* Two 1-channel sensors can also be connected as an alternative.
100
Antivalent connection of a sensor (type 1) to two channels
Antivalent connection of a sensor (type 2) to two channels*
AT40, ATD400V, ATD400K, ATD4xxW, ATD400S, ATE250S, ATD400T
System Manual, 06/2016, A2B00096162-AN