ProSoft Technology 3170-PDP - Manual (Page 19)

How Communication Takes Place and I/O Image Table Mapping 3170-PDP ♦ FLEX Platform
FLEX I/O™ PROFIBUS Adapter
ProSoft Technology, Inc. Page 19 of 152
August 23, 2007
3 How Communication Takes Place and I/O
Image Table Mapping
In This Chapter
¾ Polled I/O Structure................................................................ 20
¾ Mapping Data into the Image Table ....................................... 22
¾ Connection Status Word Definition ........................................ 42
¾ Logic Status/Analog Feedback Definition............................... 42
¾ Connection Enable Word Definition ....................................... 42
¾ Logic Command/Analog Reference Definition ....................... 42
¾ Defaults.................................................................................. 43
In this chapter, you will learn about:
ƒ
communication over the FLEX I/O backplane (between the PROFIBUS
adapter and the I/O modules)
ƒ how data is mapped into the I/O image table
One 3170-PDP PROFIBUS adapter can interface with up to eight terminal base
units with installed FLEX I/O modules, forming a FLEX I/O system of up to eight
slots. The adapter communicates to other network system components over the
PROFIBUS network. The adapter communicates with its I/O modules over the
backplane.
Inputs
Status
Outputs
Configuration
Slot 1
I/O Module
Read
Words
Write
Words
0
1
Read
Write
PROFIBUS
Adapter
Inputs
Status
Outputs
Configuration
Slot 2
I/O Module
Inputs
Status
Outputs
Configuration
Slot 8
I/O Module
Network
The I/O map for a module is divided into read words and write words. Read
words consist of input and status words, and write words consist of output and
configuration words. The number of read words or write words can be 0 or more.
The length of each I/O module's read words and write words vary in size
depending on module complexity. Each I/O module will support at least 1 input
word or 1 output word. Status and configuration are optional, depending on the
module.