Siemens SENTRON PAC RS485 - Character Frame; Figure 5-1 11-Bit Character Frame; Figure 5-2 10-Bit Character Frame

Parameter assignment/Addressing
5.1 MODBUS RTU
PAC RS485
30 Manual, 02/2008, A5E02091800B-01
Validity of the message frame
Gaps in the message frame are filled with 0xFFFFFFFF. FFFFFFFF means the message
frame contains no measured values. This means it is invalid. If the message frame has a
different content it is in principle valid.
See also
Function codes (Page 31)
5.1.2 Character frame
The MODBUS RTU specification defines the data format. The user can change the data
format.
Structure of the character frame
The data is transferred between the SENTRON PAC Power Monitoring Device and the
MODBUS master via the serial interface in an 11-bit character frame. In exceptional cases,
only 10 bits are used.
GDWDELWVVWDUWELWGDWDELWVSDULW\ELWVWRSELW
6LJQDOVWDWXV
6LJQDOVWDWXV
6LJQDOVWDWXV
6LJQDOVWDWXV
GDWDELWVVWDUWELWGDWDELWVVWRSELWV
VWDUWELW
SDULW\ELW
GDWDELWV
VWRSELW
VWDUWELW
GDWDELWV
VWRSELWV

  
  

  
  
Figure 5-1 11-bit character frame
6LJQDOVWDWXV
6LJQDOVWDWXV
GDWDELWVVWDUWELWGDWDELWVVWRSELW
VWDUWELW
GDWDELWV
VWRSELW

  
 
Figure 5-2 10-bit character frame