Chapter 15: Appendix
Participation in an existing network
When the JW-50FL receives a token within the participating token detection time, it concludes that it is linked to a network that is already established, and waits for a participation request frame up to three token cycles. During this interval, it checks for duplicate use of its node number and address, as well as updates the participation node operation table. At this time, if a node has identified a duplicate use of its address by examining the participation request frames from other nodes, it sets the common memory top address and common memory size of area 1 and 2 to zero, and does not send any cyclic data. A node that identifies duplicate use of its address will set a duplicate address flag and reset the common memory data to enable, so that the flag will be seen. If there are no problems with the node numbers, a node will send a participation request frame after the waiting time for sending a participating request frame has elapsed. The participating request frame will be sent, regardless whether it has a token or not. A node that has identified duplicate use of its node number will not send a participating request frame and will not send or receive data.
Remarks:
Participation token detection time: the time allowed to check whether the network is in operation or not.
Cycling: This refers to the point when the smallest node number receives a token that has been passed around the network.
Waiting time for sending a participation request frame: In order not to create a duplicate node number with some other node trying to enter, the participation request frame is sent after the node number x 4ms has elapsed.
Halted token detection | 1st cycle | 2nd cycle | 3rd cycle |
| | |
Participating token detection time | | |
Start monitoring | | | |
nodes | | | |
(After turning ON | | | |
the power or | | | |
when a reset is | Waiting time for sending a | |
released) | participation request frame | |
(Local node number x 4 ms)
Send a participation
request frame
Time charge setting when starting: 2
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