Cyclic Transmission Of When The Submaster Function Is Used - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

Cyclic transmission of when the submaster function is used

In cyclic transmission, data are periodically communicated among stations on the same network. Link devices (RX, RY, RWr,
RWw) are used for data communications. In the submaster function, the submaster station is performing data link in case of
disconnection of the master station; therefore, the submaster station can smoothly start to take in control if the master station
is disconnected.
Link device assignment of the master station and submaster station
Even if the control is shifted to the submaster station due to disconnection of the master station, the assignment of areas for
communications with the slave stations is the same as that of the master station; therefore, the same program can be used for
the master station and submaster station. A send area for the master station allows information to be exchanged between the
master station and the submaster station.
Link device assignment is explained using the following example of when the station No.1 and No.2 are slave stations and the
station No.3 is a submaster station.
Master operation
Station No.0
CPU module Master
station
RX, RWr
Station
No.0
Station
No.1
4
Station
No.2
Station
No.3
RY, RWw
Range of the
3
station No.0
sending data
1
Range of the
sending data to
Sending the station No.1
2
data Range of the
sending data to
the station No.2
Range of the
3
sending data to
the station No.3
■Before the control is switched
• RY/RWw assignment
 Create a program where send data to the slave stations are the same in the master station and submaster station.
 Data is sent from the master station (master operation) to the slave stations. Data does not be sent from the submaster station (submaster operation).
 Data that is sent to the master station and data that is sent to the submaster station are stored in the link devices (RX, RWr) of the submaster station.
• RX/RWr assignment
 Data that is sent from the slave stations is stored in the same area of the master station and submaster station.
 Data that is sent from the submaster station is stored in the link devices (RX, RWr) of the master station.
■After the control is switched
 Because areas of sending data to the slave stations in the submaster station are assigned in the same way as the master station, the submaster station
sends data to the slave stations as the master station does before the control is switched.
 Because areas of receiving data from the slave stations in the submaster station are assigned in the same way as the master station, the submaster station
receives data from the slave stations as the master station does before the control is switched.
Submaster
operation
Station No.3
Submaster CPU module
station
RX, RWr
Station
No.0
Station
No.1
Station
No.2 Switch
Station
No.3
RY, RWw
Station
No.0
1
Range of the
sending data to
the station No.1 Sending
Range of the data
sending data to
5
the station No.2
Range of the
station No.3
sending data
Data sent from the master operating station
Data sent from slave stations or submaster operating station
Station No.0
CPU module Master
station
RX, RWr
Station
No.0
Station
No.1
7
Station
No.2
Station
Disconnected No.3
RY, RWw
Range of the
station No.0
sending data
Range of the
sending data to
Sending the station No.1
6
data Range of the
sending data to
the station No.2
Range of the
sending data to
the station No.3
Area where data is sent to other stations
Master operation
Station No.3
Submaster CPU module
station
RX, RWr
Station
No.0
Station
No.1
Station
No.2
Station
No.3
RY, RWw
Range of the
sending data to
the station No.0
Range of the
sending data to
the station No.1 Sending
Range of the data
sending data to
the station No.2
Range of the
station No.3
sending data
1 FUNCTIONS
1.6 Submaster Function
1
69