Multi-Packet-Peer-To-Peer Transmission - Balluff BMD 1E NJ5-Serie Konfigurationsanleitung

BMD 1E_ _-_ _ _ _/_ _ _-NJ5...
Microwave Position Sensor
2
System description (continued)
2.2.2

Multi-Packet-Peer-to-Peer transmission

A Multi-Packet-Peer-to-Peer transmission is done in 3
phases: connection opening, data transmission, and
connection closing.
The following messages Request to Send, Clear to Send
and End of Message Acknowledgment are sent via PGN
Connection Management (0x00EC00 (60416
Tab. 2-1). Which message it is can be seen from the first
byte in the data field.
Connection opening:
To open the connection the sender sends a Request to
Send message (see Tab. 2-4) to the receiver. This contains
the entire size of the data to be sent in bytes, the number
of Data Transfer messages (see Tab. 2-3) in the sequence,
and the message to be sent. The recipient of this message
replies with a Clear to Send message (see Tab. 2-5). This
contains the entire size of the data to be sent in bytes, the
next sequence number and the PGN. This opens the
connection.
Data transfer:
During data transmission the data are sent as in Multi-
Packet-Broadcast transmission via Data Transfer
messages (see Tab. 2-3). The delay between the individual
messages may not exceed 200 ms. If on the receiver side
the time between two messages exceeds 750 ms,
transmission is canceled and the data are rejected.
Closing the connection:
As soon as the recipient has received the last Data
Transfer message, it sends an End of Message
Acknowledgment message (see Tab. 2-6). This contains
the entire size of sent data in bytes, the number of received
Data Transfer messages and the PGN of the received
message. This closes the connection.
The sequence of a Multi-Packet-Peer-to-Peer transmission
is illustrated in Fig. 2-3.
If the times shown in Fig. 2-3 are exceeded,
transmission is canceled and any already sent
data are rejected.
www.balluff.com
Originator
Node
), see
10
Fig. 2-3:
Data field of the PGN 0x00EC00 (60416
Byte 1
Byte 2...3
Byte 4
Byte 5
Byte 6...8
Tab. 2-4:
TR ≤ 200 ms
T1 ≤ 750 ms
T2 ≤ 1250 ms
T3 ≤ 1250 ms
n = Number of Data Transfer messages
Y = Total size in bytes
X = Control variable
RTS = Request to Send
CTS = Clear to Send
EndOfMsgACK = End of Message Acknowledgment
Multi-Packet-Pear-to-Pear transmission
to Send
0x10 (16 )
10
Total size in bytes
Number of Data Transfer messages
0xFF (255 )
10
PGN being sent (Little-Endian)
Data field of the PGN 0x00EC00 (60416
Request to Send message
english
Responder
Node
) – Request
10
) –
10
7