Time-Out Processing; Retry Processing; Initialization - Mitsubishi Electric MELSERVO-J5 Series User Manual

Time-out processing

The master station transmits EOT when the slave station does not start a return processing (STX is not received) in 300 ms
after the master station ended communication processing. Then, the master station retransmits the message in 100 ms. Time-
out occurs if the slave station does not answer after the master station has performed the above communication processing
three times. (communication error)
Controller side
(master station)
Servo side
(slave station)

Retry processing

When a fault occurs in communication between the master and slave stations, the error code in the response data from the
slave station is a negative response code ([B] to [F], [b] to [f]). In this case, the master station retransmits the message which
was sent at the occurrence of the fault (retry processing). A communication error occurs if the above processing is repeated
and results in the error three or more consecutive times.
Controller side
(master station)
Servo side
(slave station)
Similarly, when the master station detects a fault (e.g. checksum, parity) in the response data from the slave station, the
master station retransmits the message which was sent at the occurrence of the fault. A communication error occurs if the
retry processing is performed three times.

Initialization

After the slave station is switched on, it cannot return to communication until the internal initialization processing terminates.
Therefore, at power-on, start ordinary communication after doing the following:
• Wait for 3.5 s or longer after the slave station is switched on.
• Check that normal communication can be made by reading servo parameters or other data which does not pose any safety
problems.
8 COMMUNICATION FUNCTION (MITSUBISHI ELECTRIC AC SERVO PROTOCOL) [A]
404
8.3 Protocol
100 ms
300 ms 300 ms
Station No.
100 ms 100 ms
300 ms
Station No.
*Time-out
300 ms
*Communication error
Station No.