Fast Access To Module Data - Siemens S7-300 Operating Instructions Manual

D.11

Fast access to module data

Application
Very fast access to checkback and control signals is required in special applications or in an
alarm level. You can access these data directly via the input and output areas of the module.
To coordinate startup following each module startup (for example, after inserting a module,
CPU STOP → RUN), call FC CAM_CTRL continuously until the end of the startup is
indicated by RET_VAL = 0.
Note
For direct access to FM 352 data, always use the non-internal data and method described in
this section. Otherwise, your user program will encounter difficulties accessing the module.
Reading checkback signals via direct access
The byte addresses are specified relative to the output address of the module. The bit
names correspond to the names in the channel DB.
In STL, you access the data using the PIB (read 1 byte) and PID (read 4 bytes) commands.
Address
7 6
Byte 0 PARA Interna
l
Byte 1 0 0
Byte 2
Byte 3 0 0
Byte 4
Byte 5
Byte 6
Byte 7
Byte 8
Byte 9
Byte 10
Byte 11
FM 352 electronic cam controller
Operating Instructions, 05/2011, A5E01071724-03
5 4
Internal DATA_ERR
0 CAM_ACT
FVAL_DONE HYS
Programming without SFB 52 and SFB 53
Bit number
3 2
Internal DIAG
0 0
Internal
GO_P GO_M
ACT_POS
TRACK_OUT
D.11 Fast access to module data
1 0
Internal Internal
0 0
MSR_DONE SYNC
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