SMC Networks LECSB Series, Руководство по эксплуатации

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13 - 9
13. COMMUNICATION FUNCTION
13.3.5 Time-out
The master station transmits EOT when the slave station does not start reply processing (STX is not received)
300[ms] after the master station has ended communication processing. 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 communication processing three times. (Communication error)
E
O
T
300ms
100ms
E
O
T
300ms
100ms
E
O
T
300ms
100ms
300ms
Me
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Me
s
s
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Me
s
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Me
s
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*Time-out
Controller
(Master station)
Servo
(Slave station)
13.3.6 Retry
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.
Me
s
s
a
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Me
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Me
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s
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*Communication error
Controller
(Master station)
Servo
(Slave station) S
T
X S
T
X S
T
X
Station number Station number Station number
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.
PC or PLC...etc
PC or PLC...etc