RIOforFA profile handles channel-granular errors with "qualifier bits" which are transmitted in the process data frame in addition to the I/O process values, as proposed in⮫ [13].

Precondition: F-Parameter F_Passivation is set to 1 = "Channel" which is only accepted if F-Parameter F_CRC_Seed = 1, indicating a PROFIsafe V2.6 F-Device.

RIOforFA is only useable if offered from the F-Device by defined entries in the GSDML file (definition of additional qualifier bits associated to each I/O channel in combination with the F-Parameters mentioned above).

The advantage is that errors are offered immediately on channel-scope on which the safety application can react. If RIOforFA is active, the F-Host does not apply its output signal Device_Fault since it is not present in the PROFIsafe status byte (always FALSE). If at least one channel error disappears, the F-Host indicates it by setting output signal OA_Req_S. After acknowledgement (OA_C = TRUE), the F-Device sets the corresponding channel qualifier bit to TRUE to indicate that the channel delivers a valid value again.