Siemens SINUMERIK 840D sl Function Manual page 253

● Discrepancies in the F-telegram data (TelegramDiscrepancy)
NCK and PLC-F_DP drivers cyclically generate an F-telegram with diversity through 2
channels. The two F-telegrams are compared before compiling the F-telegram to be sent.
A discrepancy in the telegram data was identified in this comparison.
⇒ Alarm 27355
● Discrepancies in the output data (OutputdataDiscrepancy)
The F_DP drivers indicate their particular state using various output data. At the end of
each F_DP clock cycle, the NCK and PLC status data are compared and they must match.
⇒ Alarm 27355
The following output data are compared:
F_SENDDP (NCK)
- $A_FSDP_ERROR
- $A_FSDP_SUBS_ON
F_SENDDP (PLC)
- FSDP[1..3] or FSDP_HF[4..16].ERROR
- FSDP[1..3] or FSDP_HF[4..16].SUBS_ON
F_RECVDP(NCK)
- $A_FRDP_ERROR
- $A_FRDP_SUBS_ON
- $A_FRDP_ACK_REQ
- $A_FRDP_SENDMODE
F_RECVDP(PLC)
- FRDP[1..3] or FRDP_HF[4..16].ERROR
- FRDP[1..3] or FRDP_HF[4..16].SUBS_ON
- FRDP[1..3] or FRDP_HF[4..16].ACK_REQ
- FRDP[1..3] or FRDP_HF[4..16].SENDMODE
F_DP communication-specific system error
● SPL input/output data (SPL I/O communication) not updated. Data exchange between the
SPL and the F_DP drivers is interrupted.
⇒ Alarm 27355
● No longer any communications between the NCK and PLC
The PLC was not able to process the OB40 request for F_DP communication within the
maximum monitoring time of 500 ms.
⇒ Alarm 27355
Depending on the particular error, the cyclic processing of the F_DP driver (driver-specific
system error) or the complete F_DP communication (F_DP communication-specific system
error) is stopped and the relevant alarm is displayed. With the alarm, the NC start is locked
and STOP D/E initiated.
Behavior regarding SPL:
Stopped F_RECVDP drivers output failsafe values (0) as F-net data towards the SPL.
Behavior regarding communication partners:
Stopped F_DP drivers no longer generate any F-telegrams. At the latest after the configured
timeout time, the communication partners detect the F_DP communication failure and go into
the safe state corresponding to the specified profile.
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
8.4 Safety-related CPU-CPU communication (F_DP communication)
Connecting sensors and actuators
253