QUESTION:

Problem:
The inputs of the ASIsafe slaves which are connected via DP/AS-i F-Link are zero in the failsafe program.
The inputs are passivated and there is no possibility to reintegrate them.

There isn’t any error at the PLC (all LEDs are green, there is no group error).
At the DP/AS-i F-Link is also everything O.K., the display shows “RUN”.
At the F I/O DB of the F-Link are all channels marked as bad (QBAD = 1)

One of the following diagnostic events is entered in the diagnostic buffer for the F-CPU:
• "F-I/O passivated": Signature error (CRC)/Sequence number error ...
• "F-I/O passivated": Monitoring time for safety message frame exceeded ...
 

ANSWER:

When the DP/AS-I F-Link is configured in HW-Configuration of STEP7 the default setting in menu PROFIsafe is as follows:
F_PAR_Version: PROFIsafe V2-MODE
F_CRC_Length: 3 Byte CRC

The following F-CPUs support V2 mode:
• CPU 416F-2, Firmware Version V4.1 and higher
• CPU 416F-3 PN/DP
• CPU 315F-2 PN/DP
• CPU 317F-2 PN/DP
• CPU 317F-2 DP, as of Firmware Version V2.5
The other failsafe CPUs, e.g. CPU315F-2DP 6ES7 315-6FF01-0AB0 don’t support the PROFIsafe V2 Mode.

Solution:
In STEP7 Hardware Configuration the PROFIsafe settings have to be changed:
F_PAR_Version: PROFIsafe V1-MODE
F_CRC_Length: 2 Byte CRC
Afterwards the configuration has to be saved, compiled and downloaded.
The safety program has also to be compiled and downloaded.

For further information please take a look to the manual S7 Distributed Safety – Configuring and Programming
http://support.automation.siemens.com/WW/view/en/22099875