SYSTEM ARCHITECTURE
SNAP PAC R-Series Controller User’s Guide
16
SYSTEM ARCHITECTURE
Because SNAP PAC R-series controllers are a combination of controller and I/O processor, their architecture is
more complex than that of devices such as the SNAP EB-series brains, which are I/O processors only. The next
few pages show the capabilities of this versatile system, starting with the simplest and moving to the more
complex. Your application may require only some of these capabilities, but as your needs expand, remember
that SNAP PAC R-series I/O can be used in all the ways shown,
simultaneously
.
Understanding the SNAP PAC R-series Controller
The SNAP PAC R-series controller merges two functions that are usually located in separate pieces of hardware:
input/output processing and flowchart-based control. These two functions are handled by two “sides” of the
controller, as illustrated below.
The I/O Side of the Controller
The controller reads and writes to the I/O points using its I/O side memory map. This side of the SNAP PAC
R-series controller is like SNAP EB-series brains.
You can think of the controller’s memory map as a grid of mailboxes, with each mailbox having its own
memory address. Each mailbox address has a specific purpose. For example, one address holds the state of a
single digital point; another address holds counter data for the same point. There’s an address that stores the
controller’s firmware version, one that contains the minimum value of a specific analog point, and many more.
If you are familiar with programmable logic controllers (PLCs), you’ll see that the memory map is similar to a
register.
Write your own software applica-
tion to communicate with the sys-
tem.
C++ or Active X:
OptoMMP Com-
munication Toolkit
and controller’s
memory map.
Opto 22’s IEEE
1394-based proto-
col and controller’s
memory map.
See
OptoMMP Protocol Guide.
This task
Can be done using these methods
Details and references for information
Recommended
Alternate
The rack is shown with the SNAP PAC
R-series controller on the left and the
input/output modules on the right.
The modules on the rack connect to
devices in the real world, such as the
light bulb, to monitor or control them.
