System Configuration; Overall Configuration - Mitsubishi Electric QJ71DN91 User Manual

2 SYSTEM CONFIGURATION

2 SYSTEM CONFIGURATION

2.1 Overall Configuration

2
QJ71DN91
Master node
Terminating resistor
(121, 1/4W)
QJ71DN91
Slave node
2 - 1
This chapter explains the system configuration of DeviceNet.
The number of modules connectable to a DeviceNet network is 64, including master,
slave and master/slave nodes.
The QJ71DN91 can be used as a master node, a slave node or a master/slave node.
The following shows an example of a system configuration:
Drop line
Tap
Drop line (branch line)
Slave node
(1) DeviceNet cables, taps and terminating resistors
DeviceNet cables are used as a trunk line and drop lines.
Each node is connected to the trunk line directly, or connected to a drop line via a
tap from the trunk line. Nodes need not be wired in order of node numbers.
Connect terminating resistors at both ends of the trunk line.
(2) Network power supply unit and power supply tap
In addition to power supply for each node, connect a network power supply unit
to distribute power to the communication circuit.
Connect a power supply tap to the trunk line, and install a network power supply
unit.
POINT
To minimize the affect of noise, keep DeviceNet cables, power cables, and signal
lines of I/O modules away from each other.
Network power supply
unit (24V DC)
Slave node
Power supply tap
Slave node
MELSEC-Q
Trunk line (main line)
Terminating resistor
(121, 1/4W)
Slave node
2 - 1