Siemens SINUMERIK 840D sl Function Manual page 217

Figure 8-22
F-net data telegram
The F_SENDDP of the F-CPU1 (sender) cyclically generates an F-net data telegram and writes
it to the output data area of the F-CPU. The F-net data telegram has the following structure
that is compatible to SIMATIC:
● 6 bytes F-net data
2 bytes Bool
2x2 bytes for 2 INT values
(Notice: is not evaluated for SINUMERIK 840D sl)
● 2 byte status word
● 2 byte sequence number
● 2 byte CRC
As a result of the F_DP communication relationship - configured in SIMATIC Step7 - the F-net
data telegram is transferred from the output range of the F-CPU1 into the input range of the
F-CPU2.
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
8.4 Safety-related CPU-CPU communication (F_DP communication)
Components of an F_DP communication relationship
Connecting sensors and actuators
217