Hitachi S10mini User Manual page 251

Node monitoring started
(when the power is turned
ON or a reset is performed)
Node 1
Enter token detection time (3 s)
Node 2
Node 3
Node 254
(b) Midway enter
If a node receives the token within the enter token detection time, it concludes that a link is
already established, and does not transmit an enter request frame until the token makes three
rounds. A frame received during such an interval is used to check for node number,
address, and other duplications and update the entering node management table. If an
address duplication is detected in such an instance, the common memory starting address and
common memory size of area 1 and 2 are set to 0 and cyclic data transmission does not take
place. When a node recognizes an address duplication, it sets an address multiplexing flag
and resets the common memory data validity notification flag. If the node number is
normal, the node transmits an enter request frame after an elapse of the enter request frame
transmission wait time. The enter request frame is sent no matter whether the token is held.
When a node recognizes a node number duplication, it does not transmit an enter request
frame and refrains from entering in the network.
Enter request frame transmission
wait time (node number × 4 ms)
Figure 8-19 Startup Timing Diagram 1
Trigger Enter request
frame
Enter request frame reception wait
time (1.2 s)
8-27
8 APPENDIXES
Token