Allen-Bradley 1747-OC Series, User Manual

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1747-UM001A-US-P - March 2000
Introducing the Open Controller 1-3
Understanding the Open
Controller Architecture The architecture is basically the same for both open controllers. The
architecture consists of two CPUs (SCANNER and CONTROLLER) that
share dual-port memory. The SCANNER scans the 1746 local I/O bus and
reads/writes inputs and outputs to/from the dual-port registers. The
CONTROLLER has a PC-based architecture with either a 266 MHz
Pentium class CPU or 5x86 class CPU to run your application.
The dual port is an 8K byte memory partition that provides an interface
between the integrated SCANNER and your application software that
resides on the CONTROLLER. The 1747-OCE open controller uses an ISA
bus interface between the dual-port memory and the CONTROLLER. On
the 1747-OCF open controller, the dual-port memory and CONTROLLER
communicate across a PCI bus.
to 1746 PCI bus
dual-port memory
SCANNER
CONTROLLER (PC-based architecture)
188
CPU
bus
memory
SCANNER
software
to 1746
local I/O bus
266 MHz
Pentium
or 5x86
CPU
disk
bus
memory
BIOS
OS
application
software
open controller
CPU module
Partition: Bytes:
register 1K
commands variable
responses variable
output image variable
input image variable
host data variable
PCI bus (1747-OCF)
ISA bus (1747-OCE)
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