Communication Data Processing When Simultaneous Transmissions Occur - Mitsubishi QJ71C24/-R2 User Manual

7 DATA COMMUNICATIONS USING BIDIRECTIONAL PROTOCOL

7.3.2 Communication data processing when simultaneous transmissions occur

External device
Q series C24
External device
Q series C24
1)-1
External device
Q series C24
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Examples of the Q series C24 communication data processing for various settings of
"Simultaneous transmission data valid/invalid designation" by GX Configurator-SC are
explained.
(1) Transmission: valid, reception: valid
2)-1
E
N
Q
E
Arbitrary data
N
Q
1)-1
POINT
When the entire message of 2)-1 was received while transmitting the message of
1)-1 in the illustration.
• The Q series C24 outputs the receive data read request signal of 2)-1 to the PLC
CPU after transmitting all 1)-1. (Turns on the X3/XA.)
(2) Transmission: invalid, reception: valid
2)-1
E
Arbitrary data
N
Q
E
Arbitrary data
N
Q
(3) Transmission: valid, reception: invalid
1)-1
E
N
Arbitrary data
Q
E
Arbitrary data
N
Q
1)-1
Arbitrary data
Sum check
code
Sum check
code
Sum check
code
Sum check
code
Sum check
code
MELSEC-Q
1)-2
Sum check
code
Time check
(timer 1)
Ignores the receive
data of 1)-1.
(Generates a simultaneous
A
transmission error.)
C
K
2)-2
1)-2
A
C
K
Time check
(timer 1)
A
C
K
A
C
K
2)-2
Ignores the receive
data of 2)-1.
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