Mitsubishi Electric QJ71C24N User Manual page 203

7 DATA COMMUNICATION USING THE BIDIRECTIONAL PROTOCOL
External device
Q series C24
1)-1
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(4) Transmission: invalid, reception: invalid
2)-1
E
Arbitrary data
N
Q
E
Arbitrary data
N
Q
REMARKS
Time-check timer 1 (response monitoring time) shown in the illustration is described
in the User's Manual (Application).
POINT
When the transmission control (see User's Manual (Application)) is performed, and
the simultaneous transmission data valid/invalid designation sets that the receive
data is valid and transmission data is valid, the Q series C24 performs message
transmission and message reception processing as described below.
During message transmission processing, time check by timer 1 (response
monitoring time) is performed.
1) Message transmission (1)-1 in the illustration)
• If the Q series C24 receives a terminate transmission request (DC3
received/DR(DSR) signal OFF) from the external device during message
transmission, it terminates data transmission.
• When the Q series C24 receives the ready to send signal (DC1 received/
DR(DSR) signal ON), it restarts data transmission.
2) Message reception
• If the Q series C24 cannot send a response message to the external device
in response to message reception because the external device issued a
terminate transmission request (DC3 received/DR(DSR) signal OFF), it
transmits the response message after it receives the ready to send signal
(DC1 received/DR(DSR) signal ON) from the external device.
Sum check
code
Sum check
code
MELSEC-Q
Ignores the receive
data of 1)-1.
Generates a simultaneous
transmission error.
Ignores the receive data of 2)-1.
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