Status Information - Siemens SIMATIC S7-200 System Manual

S7-200 Programmable Controller System Manual

Status Information

There are 50 bytes of special memory (SM) allocated to each intelligent module based on its
physical position. The module updates the SM locations corresponding to the modules' relative
position to the CPU (with respect to other modules). If it is the first module, it updates SMB200
through SMB249. If it is the second module, it updates SMB250 through SMB299, and so on. See
Table A-43.
Table A-43 Special Memory Bytes SMB200 to SMB549
Intelligent
Module in
Slot 0
SMB200 to SMB250 to
SMB249 SMB299
These SM locations show default values if DP communications have not been established with a
master. After a master has written parameters and I/O configuration to the EM 277
PROFIBUS--DP module, these SM locations show the configuration set by the DP master. You
should check the protocol status byte (for example SMB224 for slot 0) to be sure that the EM 277
is currently in data exchange mode with the master before using the information in the SM
locations shown in Table A-44, or data in the V memory buffer.
Tip
You cannot configure the EM 277 PROFIBUS--DP I/O buffer sizes or buffer location by writing to
SM memory locations. Only the DP master can configure the EM 277 PROFIBUS--DP module
for DP operation.
Table A-44 Special Memory Bytes for the EM 277 PROFIBUS- -DP
Intelligent ... Intelligent
Module in Module in
Slot 0 Slot 6
SMB200 to ... SMB500 to
SMB215 SMB515
SMB216 to ... SMB516 to
SMB219 SMB519
SMW220 ... SMW520
SMB222 ... SMB522
SMB223 ... SMB523
SMB224 ... SMB524
SMB225 ... SMB525
SMW226 ... SMW526
SMB228 ... SMB528
SMB229 ... SMB529
SMB230 to ... SMB530 to
SMB249 SMB549
Note: SM locations are updated each time the DP slave module accepts configuration/ parameterization information. These
locations are updated even if a configuration/parameterization error is detected. The locations are cleared on each
power up.
444
Special Memory Bytes SMB200 to SMB549
Intelligent Intelligent
Module in Module in
Slot 1 Slot 2
SMB300 to
SMB349
Module name (16 ASCII characters)
"EM277 ProfibusDP"
S/W revision number (4 ASCII characters)
xxxx
Error code
16#0000 No error
16#0001 No user power
16#0002 to 16#FFFF Reserved
DP slave module's station address as set by address switches (0 -- 99 decimal)
Reserved
DP standard protocol status byte
MSB
0 0 0 0 0
S1 S0 DP Standard status byte description
0 0 DP communications not initiated since power on
0 1 Configuration/parameterization error detected
1 0 Currently in data exchange mode
1 1 Dropped out of data exchange mode
DP standard protocol -- address of the slave's master (0 to 126)
DP standard protocol -- V memory address of the output buffer as an offset from VB0.
DP standard protocol -- number of bytes of output data
DP standard protocol -- number of bytes of input data
Reserved -- cleared on power up
Intelligent Intelligent
Module in Module in
Slot 3 Slot 4
SMB350 to SMB400 to
SMB399 SMB449
Description
LSB
0 S1 S0
Intelligent Intelligent
Module in Module in
Slot 5 Slot 6
SMB450 to SMB500 to
SMB499 SMB549