SYSTEM ARCHITECTURE
SNAP PAC R-Series Controller User’s Guide
22
controller runs it independently. (For information on using PAC Control, see form #1700, the
PAC Control User’s Guide
, and form #1701, the
PAC Control Command Reference
.)
You use PAC Control on a PC connected to the network, so you can create your control
strategy and download it to the controller. Also included with the SNAP PAC R-series
controller is PAC Display, a full-featured human-machine interface (HMI). PAC Display uses
the same tag database as PAC Control, so points and variables are already defined.
Operators, technicians, and engineers running PAC Display on a Microsoft Windows-based
PC on the Ethernet network can see the information they need, as well as plot trends and
respond to alarms.
For applications that require more than one I/O unit, the SNAP PAC R-series controller can
control multiple I/O units through the flowcharts on its control side. These I/O units can be
located where needed on the Ethernet network for distributed control.
The following diagram shows the control side of the controller:
SNAP PAC R-series
I/O Unit
I/O Side
Read/write to points
using Memory Map
Control Side
Run PAC Control flowcharts
PAC Control
Use to create flowcharts
and download strategy
to SNAP PAC R-series
PAC Display
Uses the same
tag database as
PAC Control
Other Ethernet-based I/O units
Shared tag
database
Memory Map
