Burkert Type 8717 - Manual (Page 9)

9
Serial Communication
preamble
The preamble consists of 2 to 20 0xFF characters (differs from HART). It is used to synchronize the data transfer.
Delimiter
Telegrams are distinguished from each other mainly by the delimiter:
Message type Short frame Long frame
Master → Slave 0x02 0x82
Slave → Master 0x06 0x86
Burst message from slave 0x01 0x81
Master: PC or manual operating unit
Slave: Field device, MFC/MFM
address
The address field contains both the master address and the slave address of the message. One byte is used for this
purpose in a short frame, while 5 bytes are used in a long frame. Each device must respond to a long frame address
of 0 (= broadcast address), i.e. bit 0/1=X, bits 0 – 37=0.
The highest-order bit in both formats indicates which master is involved in communication.
(1: Primary master, continuously connected hosts;
0: Secondary master, manual operating units)
Short frame address (1 byte)
Bit 7
0 Secondary master
1 Primary master
Bit 6 0 Not in burst mode
1 In burst mode (not supported)
Bits 0 – 5 Polling address (0 – 32), bit 5 = MSB, bit 0 = LSB
m b x x x x x x
x Polling address
b Burst info
m Master address
english
MFC Family