Q9(Questions) How are communication retries carried out in a MECHATROLINK-Ⅱ network? And what happens when a communication error occurs beyond the set communication retry count?

A(Answers)

When 3 slave stations are connected in a MECHATROLINK-Ⅱ network (which for the sake of argument we will call slave #1, slave #2 and slave #3), and the maximum number of retries has been set to 3, if a communication error occurs at all the slaves, transmission/reception is retried in the sequence #1 #2  #3 within the transmission cycle.
If, with the settings described above, a communication error occurs at slave #1 only, transmission/reception is retried with respect to #1 only. If a communication error occurs in response to this retry too, the remaining two retries are not carried out although there is time for them, and the situation is treated as a communication error.


When a communication error has occurred, only one retry is carried out for each slave station within one transmission cycle. Even if there are retries remaining in the retry count, only one retry is carried out in relation to one slave. If communication still fails on execution of the retry, the situation is treated as a communication error with the slave station in question.

When cyclic communication is completed normally no retry will be carried out. However, the time required for retries is secured based on the set retry count, so no transmission state will continue for this period in this case.