S7-300 Automation System Module data 
Manual,  08/2006, A5E00105505-04 
A-1 
A Parameter sets of signal modules 
A
A.1  A.1 Principles of programming signal modules in the user program 
Parameter assignment in the user program 
You have programmed the modules in 
STEP 7
.  
In the user program, you can use a SFC: 
●  to assign new parameters to the module, and 
●  transfer the parameters from the CPU to the addressed signal module 
Parameters are stored in data records 
The signal module parameters are written to data records 0 and 1; for certain analog input 
modules, these are also written to data record 128. 
Editable parameters 
You can edit the parameters of data record 1, and then transfer these to the signal module 
using SFC55. The CPU parameters are not changed by this action! 
You cannot modify any parameters of data record 0 in the user program. 
SFCs for programming 
SFCs available for programming signal modules in the user program: 
Table A-1  SFCs for programming signal modules 
SFC no.  Identifier  Application 
55  WR_PARM  Transfer modifiable parameters (data record 1 and 28) to the addressed signal 
module. 
56  WR_DPARM  Transfer parameters (data record 0, 1 or 128) from the CPU to the addressed 
signal module. 
57  PARM_MOD  Transfer all parameters (data record 0, 1 and 128) from the CPU to the addressed 
signal module.