Mitsubishi Electric MELSEC-Q Series - Page 81

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CHAPTER 4 FUNCTIONS
4
4.1 Cyclic Transmission Function 4.1.5 Assurance of cyclic data integrity
(3) Interlock program
When handling cyclic data of more than 32 bits, interlock the data in the link relay (LB).
Handshake using link relay (LB) data can prevent data separation of the link register (LW).
Ex.
Program that sends data in W0 to W2 of station number 1 to W0 to W2 of station number 2
Handshake is performed by setting B0 to ON upon completion of storing send data.
1. The send request turns ON.
2. The contents of D0 to D2 are stored in W0 to W2.
3. Upon completion of storage in W0 to W2, B0 for handshaking turns ON.
4. By cyclic transmission, link relay (LB) data are sent after link register (LW) data transmission,
which turns ON B0 of the receiving station.
5. The contents of W0 to W2 are stored in D100 to D102.
6. Upon completion of storage in D100 to D102, B100 for handshaking turns ON.
7. When the data are sent to the receiving station, B0 turns OFF.
Cyclic transmission
Link refresh
Control station
No.1
Normal station
No.2
Send
request
SET B0
Station
No.1
Station
No.1
Station
No.2
Station
No.2
Station
No.1
Station
No.2
Station
No.1
Station
No.2
Station
No.1
Station
No.2
Station
No.1
Station
No.2
Station
No.1
Station
No.2
Station
No.1
Station
No.2
B0LB0LB0
LW0LW0
LW100 LW100
LB100
B0
W0
W100
W0
W100
B100 B100LB100
CPU module CPU module
CC-Link IE
Controller Network
module
CC-Link IE
Controller Network
module
Sending station Receiving station
Send data (W) Receive data (W)
B0
Sending station (No.1)
1.
2.
3.
7.
6.
Receiving station (No.2)
4.
5.