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CHAPTER2 Ethernet Unit
2-7 Using TELNET
Communicating by TELNET (remote operation) allows loading and editing point or
program data and operating the robot just the same if connected through an RS-232C
port.
Commands are easy to understand because they are identical to RS-232C communica-
tion commands.
2-7-1 Difference between TELNET and RS-232C communications
TELNET and RS-232C both perform the same processing. However, they use different
communication formats. This means that one format might not match your own particu-
lar system needs or objectives, so you should get a good understanding of their different
features before incorporating them into your system.
TELNET
• Easily connects to different types of systems. Can handle one versus multiple device
communications.
• Allows remote communications since it connects between separate systems.
• Basically not usable for real-time processing since real-time operation is not guaran-
teed.
RS-232C
• Basically handles one party to one party (or device) communications.
• Designed for communications between devices in close proximity.
• Operates largely to real-time specifications.
Ethernet communications protocol specifications do not guarantee real-time opera-
tion. So relying only on the Ethernet in situations such as robot emergency stop can be
extremely dangerous. Install safety interlock circuits using the emergency stop termi-
nal in the parallel I/O of the controller to ensure quick and effective emergency stops.