7 time-out operation, 8 retry operation, Communication functions – MITSUBISHI ELECTRIC J2-JRSERIES MR-J2-03A5 User Manual

Page 164

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13. COMMUNICATION FUNCTIONS

13.7 Time-Out Operation

The master station transmits EOT when the slave station does not start reply operation (STX is not
received) 300[ms] after the master station has ended communication operation. 100[ms] after that, the
master station retransmits the message. Time-out occurs if the slave station does not answer after the
master station has performed the above operation three times. (Communication error)

E

O

T

300ms

100ms

E

O

T

300ms

100ms

E

O

T

300ms

100ms

300ms

Me

ss

a

g

e

Me

ss

a

g

e

Me

ss

a

g

e

Me

ss

a

g

e

*Time-out

Controller
(Master station)

Servo
(Slave station)

13.8 Retry Operation

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 operation). A
communication error occurs if the above operation is repeated and results in the error three or more
consecutive times.

Me

ss

a

g

e

Me

ss

a

g

e

Me

ss

a

g

e

*Communication error

Controller
(Master station)

Servo
(Slave station)

S
T
X

S
T
X

S
T
X

S

ta

tio

n num

ber

S

ta

tio

n num

ber

S

ta

tio

n num

ber

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 operation is performed three times.

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