CHAPTER 2

COMMUNICATION SPECIFICATIONS

The following are the communication specifications of the built-in Ethernet port of the CPU module.

Item Specification

Transmission specifications

Data transfer speed

Communication mode

Transmission method

Maximum distance between hub and node

Maximum number of nodes/ connection

TCP/IP

10BASE-T

100BASE-TX

100 or 10 Mbps

Full-duplex or half-duplex

Base band

100 m

Cascade connection: Up to four

*2

Cascade connection: Up to two

*2

Number of connections

Connection cable

*1

UDP/IP

10BASE-T

100BASE-TX

Total of 16 for socket communications, MELSOFT connections, and MC protocol.

One for FTP

Ethernet cable of category 3 or higher (STP/UTP cable)

*3

Ethernet cable of category 5 or higher (STP cable)

*1 Straight cables can be used.

When the CPU module is directly connected to GOT with Ethernet cable, a cross cable of Category 5e or lower can also be used.

*2 This number applies when a repeater hub is used.

When using a switching hub, check the number of cascaded stages with the manufacturer of the hub to be used.

*3 Use of STP cables is recommended in an environment with noise.

Hubs with 10BASE-T or 100BASE-TX ports

*4

can be used.

Up to 16 external devices can access one CPU module at the same time.

*4 The ports must comply with the IEEE802.3 10BASE-T or IEEE802.3 100BASE-TX standards.

● When connected to a hub, the CPU module determines the cable used (10BASE-T or 100BASE-TX) and the communication mode (full-duplex or half-duplex) according to the hub.

Set the hub into the half-duplex mode if the hub that does not have the auto-negotiation function.

● The operation of commercial devices used for the following applications is not guaranteed. Check the operation before using the module.

• Internet (general public line)

(Internet-access service offered by an Internet service provider or a telecommunications carrier)

• Firewall device(s)

• Broadband router(s)

• Wireless LAN

● If Ethernet communication is performed with "Specify service process execution counts" selected for "Service processing setting" in the PLC system tab of PLC parameter, a scan time increases by time for service processing. (approximately

500ms)

To reduce it to 500ms or less, select an item other than "Specify service process execution counts".

(Example: Select "Specify service process time" and then enter a time value.)

● If broadcast storm occurs in the network, scan time may be increased.

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CHAPTER 2 COMMUNICATION SPECIFICATIONS

Remark

TCP and UDP are defined as follows:

• TCP (Transmission Control Protocol)

In communications among programmable controllers and networked devices, this protocol establishes a connection between port numbers of the two devices to perform reliable data communications.

• UDP (User Datagram Protocol)

This is a connectionless protocol and thereby its speed is faster than that of TCP. However, the reliability in data communications is low. (Data may be lost or not be received in correct order.) Note that simultaneous broadcast is available.

Select an appropriate protocol, considering the specifications of the external device and the characteristics of the above protocols.

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