Siemens SINUMERIK 840D sl Function Manual page 520

Data descriptions
9.7 System variable
System variable $A_FSDP_SUBS_ON
The system variable is used to indicate that substitute values are output to the application at
F_RECVDP (receiver).
0 = output of process values
1 = output of substitute values
System variable $A_FSDP_DIAG
This system variable is used to indicate the cause of the communication error determined by
F_SENDDP.
Bits 0 - 3: Reserved
Bit 4: 1 = timeout detected
Bit 5: 1 = sequence number error detected
Bit 6: 1 = CRC error detected
Bit 7 - 12: Reserved
Bit 13: 1 = discrepancy in the F-telegram data (TelegramDiscrepancy)
Bit 14: 1 = sign-of-life monitoring (LifeSign)
Bit 15: 1 = asynchronous fault state (StateFault)
System variable $A_FRDP_SUBS
Substitute values that are output to the SPL in the following states are entered using the system
variable:
● Start of cyclic communication
● Communication error
Changes to the substitute values always become effective in the next F_DP clock cycle, even
during a fault situation.
Default value: After the control boots, initially, the values saved in MD $MN_SAFE_RDP_SUBS
become active.
System variable $A_FRDP_ERR_REAC
The response when a communication error occurs is set using the system variable. Depending
on the actual interdependency of the two plant/system components involved, the response to
a communication error, caused by a communication path error or by consciously switching off
one the plant/system components can be specifically entered.
0 = Alarm 27350 + Stop D/E
1 = Alarm 27350
2 = Alarm 27351 (only display, self-clearing)
3 = no system response
Note
520
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety Integrated