Yaskawa JAPMC-MC2303-E - Manual (Page 160)

Appendix B FL-net Network Management
B.2 Joining/Leaving FL-net
A-10
[ b ] Joining FL-net at a Halfway Point
When the token has been received within the join token detection time, each node waits for join request frame sending
until the token has circulated three times, assuming that the link has already been established. Meanwhile, each node
checks for the presence of duplicate node numbers and addresses using the received frame, and updates the join node
management table. At this time, if a node recognizes the presence of a duplicate address, it sets the common memory
leading addresses of areas 1 and 2 and the common memory size to 0 and does not sends cyclic data. In addition, the
node sets the duplicate address detection flag and resets the common memory data valid notification flag. When there
is no error with the node number (no duplicate address is found), the node sends a join request frame after the join
request frame send waiting time elapses. The join request frame is sent regardless of whether the token is being held by
the node.
When a duplicate node number is found, the node will neither send the join request frame nor join the network.
ΠJoin token detection time: Time required to check whether the network is active or not.
ΠCirculation: Circulation is started when the token sent to the smallest node number has been received.
Œ Join request frame send waiting time: A join request frame is sent after an elapse of local node number × 4 ms to
avoid the duplication of other newly joined nodes (refer to the following figure).
( 2 ) Leaving from FL-net
Each node checks a node number each time it receives a token frame, and determines that the node has left the network
if no token frame is received three consecutive times from that node.
(This is also true when the token holding node does not pass the token even after the token monitoring time has
elapsed.)
As shown above, when it is determined that a node has left the network, each node deletes its information from the
management table.
N ψ1 N ψ2 3 ψ4 4 ψ5
First cycle
N→1
Join request frame waiting time
(Local node number) × 4 ms
N ψ1 N ψ2
Second cycle
N ψ1 N ψ2
Third cycle
N ψ1
Join request frame
sending
Cancellation of token detection
Join token detection time
Start of node monitoring
(At power ON or reset cancellation)