ProSoft Technology MVI69-FLN - Manual (Page 108)

MVI69-FLN ♦ CompactLogix Platform Reference
FA Control Network Communication Module
Page 108 of 137 ProSoft Technology, Inc.
November 3, 2008
3.5.7 Masterless Transmission Management
Token
Basically, while a node holds a token, the node can transmit data.
In the following two cases, however, transmission is enabled without a token.
That is, one is reissue of token due to a token monitoring time is up and the other
is a transmission of participation request frame when the node has not joined in
the network.
1 In the FL-net, a single token is circulated among nodes. A node receiving a
token, this node will hold the transmission right until it releases the token to
the next node.
2 The token is circulated among all the nodes joining in the FL-net.
3 The token can be transmitted together with cyclic data.
4 The token can also be circulated without any data.
5 The token is monitored by the timer of each node. If the token is not sent in
the network for a fixed time, another token will be reissued automatically.
6 If there are two tokens in the network, they are unified into one.
Token flow
Only one token exists in the network.
A frame including a token (token frame) is provided with a node number of
destination and node number of token transmitting side. Each node becomes a
token holding node when a match is found with the destination node number of
the received token frame.
The token rotation order is determined in the ascending order of node number.
The node with the largest node number releases a token to the node with the
smallest node number.