ECT 464

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ECT 464

• Lecture 19
• Communications

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• Todays Quote
• Remember the banana When it left the bunch, it
  got skinned.
• Let us not give up meeting together, as some are
  in the habit of doing, but let us encourage one
  anotherand all the more as you see the Day
  approaching.
• Hebrews 1025

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Communication Methods

• ASCII strings
• DF1 RS-232 connections
• MSG command
• DH-485
• Ethernet
• Modbus RTU Master
• DeviceNet
• Wireless
• 900 MHz

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Data Highway Configuration
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Devicenet Configuration
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Mixed Configuration
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Mixed Configuration
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ASCII Instructions
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Service Communications

• Under normal operation the controller processes
  communications once every time it scans the
  control program. If you require the
  communications port to be scanned more often, or
  if the ladder scan is long, you can add an SVC
  (Service Communications) instruction to your
  control program. The SVC instruction is used to
  improve communications performance/throughput,
  but also causes the ladder scan to be longer.

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Service Communications
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Message
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Messages

• The controller is capable of communicating using
  local or remote messages. With a local message,
  all devices are accessible without a separate
  device acting as a bridge. Different types of
  electrical interfaces may be required to connect
  to the network, but the network is still
  classified as a local network. Remote messages
  use a remote network, where devices are
  accessible only by passing or routing through a
  device to another network.

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Message Elements

• The message file uses 24 different elements to
  control several aspects of the message. Some
  elements are
• Address (Bridge and Node)
• Type
• Channel and Target
• Time Out information
• Other Control Parameters