Burkert Type 8717 - Manual (Page 8)

8
Serial Communication
telegram
general information
The layout of the transmission telegram is based on the HART protocol. HART is a master slave protocol, i.e. each
transmission is started by a master device (PC or manual operating unit). The slave device (field device, MFC / MFM)
responds only to a master telegram if the device was addressed by the telegram.
Exception: Burst message
Additional information about the HART protocol may be found under:
http://www.hartcomm.org/
http://www.romilly.co.uk/
A distinction is drawn between short frame and long frame telegrams. They consist of the following characters:
Short frame
Preamble 2 – 20 bytes 0xFF
delimiter 1 byte
Master → Slave 0x02
Slave → Master 0x06
Burst message
0x01
Address 1 byte
(Master address + Burst info + Polling address)
Command 1 byte
Byte count 1 byte
Status 2 bytes, for slave Master
(for meaning see “3.3. Error messages” )
data 0 – 255 bytes
Checksum 1 byte
long frame
Preamble 2 – 20 bytes 0xFF
delimiter 1 byte
Master → Slave 0x82
Slave → Master 0x86
Burst message
0x81
Address 5 bytes
Command 5 bytes
Byte count 1 byte
Status 2 bytes, for slave Master
(for meaning see “3.3. Error messages”)
data 0 – 255 bytes
Checksum 1 byte
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MFC Family