Difference between revisions of "BACnet MS/TP"

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MS/TP Frame Format
 
MS/TP Frame Format
  
0x55
 
  
0xFF
 
  
Frame Type
 
  
Dest MAC
 
  
Src MAC
 
  
Len MSByte
 
  
Len LSByte
 
  
Header CRC
 
  
Data if len non zero
 
  
 +
 +
 +
 +
 +
{| border="1" cellpadding="10" cellspacing="0"
 +
|+ align="top" | '''Network Layer Message Type(First Byte of [[NSDU]])'''
 +
|0x55 || Framing 1
 +
|-
 +
|0xFF || Framing 2
 +
|-
 +
|Frame Type ||
 +
|-
 +
|Dest MAC ||
 +
|-
 +
|Src MAC ||
 +
|-
 +
|Len MSByte ||
 +
|-
 +
|Len LSByte ||
 +
|-
 +
|Header CRC ||
 +
|-
 +
|Data || if len non-zero
 +
|-
 +
| Data CRC MSByte || if len non-zero
 +
|-
 +
| Data CRC LSByte || if len non-zero
 +
|}
  
 
{{Keyword List}}
 
{{Keyword List}}

Revision as of 07:51, 14 September 2018

BACnet "Master-Slave/Token-Passing" is the optional, RS-485 based physical layer for BACnet. It is based on cheap, relatively slow, serial communications.


Starting with Addendum 135-2008ab, 9600 and 38400 are the required baud rates and all of the others (19200, 57600, 76800, and 115200) are optional

MS/TP Frame Format








Network Layer Message Type(First Byte of NSDU)
0x55 Framing 1
0xFF Framing 2
Frame Type
Dest MAC
Src MAC
Len MSByte
Len LSByte
Header CRC
Data if len non-zero
Data CRC MSByte if len non-zero
Data CRC LSByte if len non-zero
Keyword List
APDU BBMD BVLC BVLL DADR DNET Encoding I-Am LSAP MAC NPCI NPDU NSAP NSDU SA SADR SNET

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