Allen-Bradley DeviceNet 1756-DNB - Planning Your Configuration

Chapter 1
Publication 1756–6.5.15 – July 1998
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This chapter introduces questions you should ask before configuring
your 1756–DNB communication module. In addition, it presents an
example DeviceNet network and I/O data mapping scheme.
For information about See page
What you need to know 1–1
Beginning the process 1–1
Planning example 1–2
Mapping input data 1–3
Mapping input data 1–4
Mapping output data 1–5
To map data via your communication module, you must understand:
• your network requirements
• how to map input data
• how to map output data
Planning before configuring your communication module helps
make sure that you can:
• use your memory and bandwidth efficiently
• cater to device-specific needs and requirements
• give priority to critical I/O transfers
• leave room for expansion
A very important question to answer is “what is on your network?”
You should be familiar with each device’s:
• communication requirements
• I/O importance and size
• frequency of message delivery
You should also ask “how might this network appear in the future?”
At this point in your planning, it is advantageous for you to have
some idea of how the network could be expanded. When mapping
your I/O, you have the opportunity to allot room for future I/O. This
can save time and effort in the future.
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