Rockwell Automation 2755-DM9, -DM9E High Speed Decoder - Manual (Page 20)

A–B
3 Chapter
3–1
How the Decoder Operates
This chapter provides a brief description of how the decoder operates. We
also provide a brief description of how the decoder communicates with host
devices.
Figure 3.1 is a block diagram of the decoder.
Figure 3.1
Catalog Number 2755-DM9 Decoder
DECODER
POWER
SUPPLY
LASER SCAN HEAD
DATA
ACQUISITION I/O MICROPROCESSOR
POWER SUPPLY - An internal power supply provides power for both the
laser scan head and internal circuitry of the decoder. As stated earlier, the
source voltage may range from 85 to 264 volts AC. The power supply will
automatically adjust to the input voltage.
DATA ACQUISITION CIRCUIT - The data acquisition circuitry of the
decoder receives both video and synchronization signals from the laser scan
head. The data acquisition circuitry filters and stores blocks of data received
from the scan head in the Random Access Memory (RAM) of the decoder.
Chapter Objectives
How the Decoder Operates