Technical data

Table Of Contents
Generating Block-Related Messages
System Software for S7-300/400 System and Standard Functions - Volume 2/2
A5E00739858-01
24-39
24.17 Reading Dynamic System Resources with SFC 106
"DEL_SI"
How dynamic system resources develop when generating messages with the
SFCs 107 and 108
When messages are generated with SFCs 107 "ALARM_DQ" and 108
"ALARM_D", the operating system occupies temporarily system memory space.
For example, if you do not delete a FB that exists in the CPU with SFC 107 or SFC
108 calls it may happen that corresponding system resources stay permanently
occupied. If you reload the FB with SFC 108 or SFC 108 calls, it may happen that
the SFCs 107 and 108 are not processed properly anymore.
Description
With SFC 106 "DEL_SI" you can delete currently used system resources.
SFC 106 "DEL_SI" has three possible operating modes explained in the table
below. Set the desired operating mode via the MODE parameter.
MODE Which of the system resources occupied by SFC 107/SFC 108 are deleted?
1 All (call of SFC 106 with SI_ID:=0)
2 The system resource occupied by the call of SFC 107-/SFC 108 with EV_ID:=ev_id (call of the
SFC 106 with SI_ID:=ev_id)
3 The system resource occupied by the call of SFC 107-/SFC 108 with CMP_ID:=cmp_id (call of
the SFC 106 with SI_ID:=ev_id)
Parameters Declaration Data type Memory Area Description
MODE INPUT INT I, Q, M, D, L, Const. Job identifier
Permissible values
1: delete all system resources
2: delete the system resource that
was occupied with EV_ID = ev_id
when SFC 107-/SFC 108 was called
3: delete the system resources that
were occupied with CMP_ID =
cmp_id when SFC 107-/SFC 108
was called
SI_ID INPUT DWORD I, Q, M, D, L, Const. ID of the system resource(s) to be
deleted
Permissible values
0, if MODE=1
Message number ev_id, if MODE=2
ID cmp_id for identification of the
system section, if MODE=3
RET_VAL OUTPUT INT I, Q, M, D, L Error Information