Yamaha SRCD, ERCX, DRCX, SRCX Using Telnet, Difference between Telnet and RS-232C communications

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.

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