Technical data

S7 Communication
System Software for S7-300/400 System and Standard Functions - Volume 2/2
21-36 A5E00739858-01
21.11 Initiating a Warm or Cold Restart on a Remote Device
with SFB 19 "START"
Description
If there is a rising edge at control input REQ, SFB 19 "START," this activates a
warm or cold restart on the remote device addressed by the ID. If the remote
system is a fault-tolerant system, the effect of the restart request depends on the
parameter PI_NAME: the start request is valid either for exactly one CPU or for all
CPUs of this system. The following conditions must be met if the remote device is a
CPU:
• The CPU must be in the STOP mode.
• The key switch of the CPU must be set to "RUN" or "RUN-P."
Once the warm or cold restart is completed, the device changes to the RUN mode
and sends a positive execution acknowledgement. When the positive
acknowledgement is evaluated, the status parameter DONE is set to 1. If any
errors occur, they are indicated by the status parameters ERROR and STATUS.
A further warm or cold restart can only be activated in the same remote device
after the last complete restart is completed.
Parameter Declaration Data Type Memory Area Description
REQ INPUT BOOL I, Q, M, D, L Control parameter request, activates the
SFB at a rising edge
ID INPUT WORD I, Q, M, D,
constant
Addressing parameter ID, refer to Common
Parameters of the SFBs/FBs and SFCs/FCs
for S7 Communication
DONE OUTPUT BOOL I, Q, M, D, L DONE status parameter:
0: Job not started or still running
1: Job has been executed error-free
ERROR
STATUS
OUTPUT
OUTPUT
BOOL
WORD
I, Q, M, D, L
I, Q, M, D, L
ERROR and STATUS state parameters,
error display:
ERROR=0 and STATUS has the value:
0000H: neither warning nor error
<> 0000H: Warning, STATUS supplies
detailed information
ERROR=1
There is an error. STATUS supplies
detailed information on the type of
error.