Specifications

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CHAPTER 4 ASSIGNMENT II (TRANSIENT TRANSMISSION)
The configuration of the exercise system is the same as that of Assignment I.
4.1 Transient Transmission Function
The transient transmission function performs data communication only when it is
requested between stations.
The transient transmission function can be requested by GX Developer, the intelligent
function module, the dedicated link instructions (SEND, RECV, READ, WRITE, REQ,
ZNRD, ZNWR and RECV), etc.
In the MELSECNET/H, data communication can be performed with other stations
having the same network number (the same network as the host is connected), as well
as with the stations having other network numbers.
4.1.1 Types and descriptions of dedicated link instructions
The following table outlines the instructions that can be used for the MELSECNET/H.
For details on the format and program examples of each instruction, see the applicable
section listed in the Reference section column.
Dedicated Link Instruction List
: Can be used by both the control and normal stations : Cannot be used
Executing
station
Target station
Instruction Name
QCPU
Description
QCPU QnACPU AnUCPU
SEND Send data
RECV Receive data
SEND: Writes data to the target station (network module) having the target network
number.
RECV: Reads the data sent with SEND to the CPU device.
CPU
Network
module
Channel 1
SEND
RECV
Logical channel 1 (Channel 1)
Network
module
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
Channel 7
Channel 8
Logical channel 2 (Channel 2)
Logical channel 3 (Channel 3)
Logical channel 4 (Channel 4)
Logical channel 5 (Channel 5)
Logical channel 6 (Channel 6)
Logical channel 7 (Channel 7)
Logical channel 8 (Channel 8)
CPU
READ
SREAD
Read word
device from
other station
Reads the CPU device data (16-bit units) from the target station having the target
network number.
2594
READ
Word device
CPU
Network
module
Network
module
CPU
2594
Word device
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
Channel 7
Channel 8
WRITE
SWRITE
Write word
device to
other station
Writes data (16-bit units) to the CPU device of the target station having the target
network number.
(SWRITE can turn on the device of the target station.)
WRITE
361
CPU
Network
module
Network
module
CPU
Word deviceChannel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
Channel 7
Channel 8