Overview Of Data Communication Via Network; Cyclic Transmission - Mitsubishi Electric MELSEC Q Series User Manual

13.1

Overview of Data Communication via Network

There are main types of data communication from the C Controller module via each network.
Transmission
Description
type
Communication method to
Cyclic automatically transmit/receive
transmission data range predefined in the
network parameters in a cycle.
Communication method to
Transient transmit/receive data during cyclic
transmission transmission only upon
communication request.
There are following types of each transmission method.
Transmission
type

Cyclic transmission

Transient
transmission
Section 13.2 and Section 13.3 describe the overall functions.
For each network function, refer to the following.
Page 225, Section 13.4
13.2
Cyclic Transmission
Cyclic transmission is a transmission method specific to the programmable controller network.
A data area dedicated to the network, called a link device, is used for cyclic and automatic transmission/reception of
data.
(1) Data flow
Data flow in cyclic transmission is illustrated below.
C Controller module
1) The sending C Controller module writes data to the network module link device.
2) The sending link device data are stored in the receiving link device by link scan.
3) The receiving C Controller module reads data from the network module link device.
From the user program, uses the host network module link
device controlled by the C Controller module.
Data are transmitted/received between networks by the
cyclic transmission function of the network module.
From the user program, specifies and accesses the
network module device(s) or buffer memory, etc. of the
other destination stations' network module via the network.
Access method
Access by link refresh function
Direct access
Buffer memory access
Message communication
Other station device access
Sending side
network module
1)
Link
device
CHAPTER 13 FUNCTIONS ACCESSED VIA A NETWORK MODULE
Access target
Reference
Page 212, Section 13.2.1
Page 217, Section 13.2.2
Page 219, Section 13.2.3
Page 221, Section 13.3.1
Page 223, Section 13.3.2
Q24DHC-V Q24DHC-VG
Receiving side
network module
2)
3)
Link
Link
device
scan
Reference
Page 209, Section
13.2
Page 221, Section
13.3
Q24DHC-LS Q26DHC-LS Q12DC-V
C Controller module
209
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