Siemens Sinumerik 840D sl Function Manual page 266

Connecting Sensors/Actuators
7.4 Safety- -related CPU- -CPU communication (F_DP communication)
Boundary conditions
1. For a communication error, the following system variables are always set inde-
pendent of the error response set using the system variable
$A_FRDP_ERR_REAC[1...n]:
-- $A_FRDP_ERROR[1...n] = 1
-- $A_FRDP_SUBS_ON[1...n] = 1
-- SPL input values $A_INSE[1...n] = $A_FRDP_SUBS[1...n]
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 (in time).
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_FRDP_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_RDP_ERR_REAC is active.
System variable: Substitute values, $A_FRDP_SUBS
Using the system variable $A_FRDP_SUBS[1...n], substitute values are specified,
which, in the case of an error, are output to the SPL input data parameterized
using machine data $MN_SAFE_RDP_ASSIGN. A change to the substitute values
only becomes effective in the next F_DP clock cycle -- also during an error.
The system variable $A_FRDP_SUBS[1...n] is a part of the crosswise data com-
parison SPL--CDC.
Note
Until the system variables are programmed for the first time, after the control
boots, the values defined using MD $MN_SAFE_RDP_SUBS[1...n] are active.
System variable: User acknowledgment, interface signal:
DB18.FRDP_ACK_Rei and channel_1 reset
A user acknowledgment is always required after a communication error detected
by F_RECVDP (system variable $A_FRDP_ERROR = 1). Once the cause of the
error has been removed and F_SENDDP and F_RECVDP are again in cyclic com-
munication, F_RECVDP sets the request for user acknowledgment via the system
variable $A_FRDP_ACK_REI = 1.
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
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