2 - 4 2 - 4
MELSEC-Q
2 SYSTEM CONFIGURATION
2.2 Devices Necessary for Network Configuration
This section explains the devices that configure a network.
Please note that the network must be installed by qualified networking specialists to
take sufficient safety measures.
The 10BASE-T or 100BASE-TX can be used to connect the QJ71MT91 to a network.
The QJ71MT91 will distinguish between 10BASE-T and 100BASE-TX, and between
the full duplex and half duplex communication mode according to the hub type.
However, for connection with the hub that does not have the auto negotiation function,
set the half duplex communication mode on the hub side.
MODBUS /TCP slave device MODBUS /TCP master device
Twisted pair cable
Hub (
1)
*1
Target device
QJ71MT91
R
R
Cascade connection is allowd for up to
two stages when 100BASE-TX is used, or
up to four stages when 10BASE-T is used.
Use the devices that comply with the IEEE802.3 100BASE-TX/10BASE-T Standard.
(1) Hub and other equipment
(a) Shielded twisted pair cable
1) For 100BASE-TX
Shielded twisted pair cable (STP cable), Category 5
2) For 10BASE-T
Unshielded twisted pair cable (UTP cable), Category 3 (4, 5)
A straight cable can be used.
(We do not guarantee proper operation if a crossing cable is used for the
100BASE-TX/10BASE-T connection between the QJ71MT91 and the
target device.)
(b) RJ45 jack
(c) Hub for 100Mbps/10Mbps network
POINT
In high-speed communication (100Mbps) by the 100BASE-TX connection, a
communication error may occur under the influence of high frequency noise from
devices other than the programmable controller in the installation environment.
Take the following action on the QJ71MT91 side to prevent the influence of high
frequency noise in the construction of a network system.
(1) Wiring connection
Do not install a twisted pain cable together with the main circuit and power
cables, etc.
Place the twisted pair cable in a duct.
(2) Communication system
Increase the number of communication retries if necessary.
Change the hub used for connection into a 10Mbps hub, and make
communication at a transmission speed of 10Mbps.