SYSTEM ARCHITECTURE
SNAP PAC R-Series Controller User’s Guide
20
The following graphic shows how these software applications (and some hardware, too) can directly access
the memory map in the controller’s I/O side for both I/O point data and strategy variable data.
All of the protocols shown in the diagram, except FTP, can be used to communicate with both the fixed
memory map area and the Scratch Pad area, so you can access both I/O point data in the fixed area and
strategy variable data placed in the Scratch Pad area. In addition, strategy variable data from the PAC Control
database can be directly used by OPC clients.
FTP can be used to access files on the SNAP PAC R-series controller, which are on the control side but can
contain data from the I/O side (or any other data). For more information on the controller’s file system and FTP,
see the
PAC Control User’s Guide
and the
PAC Manager User’s Guide
.
The Complete System
When all these capabilities we’ve discussed are put together, you can see the versatility—and the wealth of
applications—of the SNAP PAC R-series I/O system, shown on the following page.
All protocols except FTP
can also read strategy
variable data from the
Scratch Pad area of the
Memory Map.
All protocols except
FTP can read or write
to I/O points directly
through the Memory
Map.
SNAP PAC R-series
controller
I/O Side
Read/write to points
using Memory Map
Control Side
Run PAC Control flowcharts
Fixed memory area
(I/O point data)
Paging
Scratch pad area
(strategy variable
Modbus/TCP
hardware and
software
File system
Enterprise
database
Any OPC
client software
3rd-party
software
•
Intellution
•
Wonderware
ActiveX custom
application
(VB, C, C++,
database)
Enterprise
management
system
SMTP
SNMP
Modbus/TCP
1394-based
OPC
FTP
HTTP/HTTPS server
RESTful API
Databases
Other systems
IoT applications
