Allen-Bradley DeviceNet 1784-PCIDS, Руководство пользователя, Страница: 30 / 101

Publication 1784-6.5.30 - February 2001
2-8 Planning Your Configuration and Data Mapping Your Devices
Mapping Photoeye Input Data
The photoeye’s input byte is mapped to the scanner’s input data table.
What’s Next?
Chapter 3 describes how to set up the system hardware for the
example network.
What’s Happening?
Important : The scanner only makes the
data available for the host application to
read. The scanner does not move the
data to the host application.
= unused bits
1
Photoeye Input Byte
1
2
The status and data bits from
the photoeye are mapped into
the scanner’s input data table.
- Bit 8 (“D”) turns on.
The host application reads
word zero into its input data
file and reacts accordingly.
S D
2
Word 0
Word 1
Word 2
Word 3
Word 4
Word 1023
1784-PCIDS Scanner Input Image Table
1
S D
Word 0 0000 00 SD 0000 0000
Word 1 0000 0000 0000 0000
Word 2 0000 0000 0000 0000
Word 3 0000 0000 0000 0000
Word 5 0000 0000 0000 0000
Word 4 0000 0000 0000 0000
Host application
Input Data File
Example: The Data bit from the photoeye
appears in word 0, bit 8 in the host
application’s input image table.
The Status bit from the photoeye appears in
word 0, bit 9 in the host application’s input
image table.
Word 5
up to
1
This mapping is based upon the example in chapter 5.
The mapping for your system may be different.
photoelectric sensor node address 9
RediSTATION input byte
An object passes in front of the
photoeye.