XPSFB3411 is obsolete and can be replaced by XPSMP11123
Here is the difference between them:
The old module XPSFB3411 provided a dynamic monitoring during the 2 contacts change-over on the same limit switch.
This dynamic monitoring doesn't exist in any configuration of the XPSMP using 2 limit switches in combined mode.
XPSMP has similar function in the configurations 5.
XPSMP requires an initial test (guard opening and re-closing) at power on - start locking - and the time window control between the actuation of the 2 switches is monitored (1.5s).
But the dynamic monitoring between the 2 contacts (NC & NO) in the same switch on XPSMP doesn't exist.
So it is not completely the same function