Other signal modules 
  7.4 Position  decoder module SM 338; POS-INPUT; (6ES7338-4BC01-0AB0) 
S7-300 Automation System Module data 
Manual,  08/2006, A5E00105505-04 
7-15 
 
Note 
The Freeze function is acknowledged automatically when you assign new parameters with 
different arguments to the relevant  
channel.  
The freeze function remains unaffected if you set parameters with identical arguments. 
 
See also 
SM 338; POS-INPUT addressing (Page 7-16) 
SM 338; POS-INPUT programming (Page 7-15) 
7.4.3  SM 338; POS-INPUT programming 
Programming 
You program the SM 338; POS-INPUT in 
STEP 7
. Always program the module while the 
CPU is in STOP mode.  
After you completed the parameter declaration, download the parameters from the PG to the 
CPU. At its next STOP → RUN transition, the CPU transfers the parameters to the SM 338.  
New parameters can not be assigned by the user program. 
Parameters of SM 338; POS-INPUT 
The table below provides an overview of configurable parameters and defaults for the SM 
338. 
The defaults apply if you have not set any parameters in 
STEP 7
 (default setting bold). 
Table 7-3  Parameters of SM 338; POS-INPUT 
Parameters  Range of values  Note 
Enable 
•  Fast-Mode 
 
Yes / no 
Enable parameter. 
Applies to all 3 channels. 
Enable 
•  Diagnostic interrupt 
 
Yes / no 
Enable parameter. 
Applies to all 3 channels. 
Absolute value encoder (SSI) 
 
1)
 
none; 13 bits; 21 bits; 25 bits  none: The encoder input is switched 
off. 
Code type 
1)
  Gray; Binary  Code returned by the encoder. 
Transmission rate 
 1) ,3)
  125 kHz; 250 kHz; 500 kHz; 1 MHz  Data transfer rate of the SSI position 
detection. Observe the relationship 
between cable lengths and the 
transmission rate (see Technical data)