Siemens Sinumerik 840D sl Function Manual page 255

10/15
Boundary conditions
1. For a communication error, the following system variables are always set
independent of the error response set using the system variable
$A_FSDP_ERR_REAC:
-- $A_FSDP_ERROR = 1
-- $A_FSDP_SUBS_ON = 1
2. When a communication error occurs, the currently programmed error response
is realized. If the error response is changed, it only becomes effective when the
next communication error occurs.
3. Whether STOP D or STOP E is initiated as error response can be parame-
terized using:
-- NCK: $MN_SAFE_SPL_STOP_MODE
-- PLC: DB18.DBX36.1
4. The system variable $A_FSDP_ERR_REAC[1...n] is a part of the crosswise
data comparison SPL--CDC.
Note
Until the system variable is programmed for the first time, after the control boots,
the value set using MD $MN_SAFE_SDP_ERR_REAC is active.
Output data, F_SENDDP
System variable: Error signal, $A_FSDP_ERROR
System variable $A_FSDP_ERR_REAC[1...n] is used to indicate that there is a
communication error. The specific cause, determined by F_SENDDP, is communi-
cated using the diagnostics data (system variable $A_FSDP_DIAG).
The system variable $A_FSDP_ERROR is cyclically compared with the corre-
sponding PLC variables FSDP[1...16].ERROR. If unequal, there is a system error
and this is displayed using Alarm 27355 "F_DP: %1 communication, connection
%2 reports a system error %3 (%4)".
System variable: Substitute value signal, $A_FSDP_SUBS_ON
System variable $A_FSDP_SUBS_ON[1...n] is used to signal that F_RECVDP has
output substitute values to the application.
The system variable $A_FSDP_SUBS_ON is cyclically compared with the corre-
sponding PLC variables FSDP[1...16].SUBS_ON. If unequal, there is a system
error and this is displayed using Alarm 27355 "F_DP: %1 communication, connec-
tion %2 reports a system error %3 (%4)".
© Siemens AG 2015 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
7.4 Safety- -related CPU- -CPU communication (F_DP communication)
Connecting Sensors/Actuators
7-255