ARCHITECTURAL DIAGRAMS
SNAP PAC S-Series User’s Guide
8
Connections to Legacy Serial-based I/O Units
In the following diagram, a SNAP PAC S-series controller is connected to Opto 22 legacy serial-based I/O units
over an RS-485 serial network. The controller is also connected to a larger, separate enterprise Ethernet
network to provide process data to a PC running Opto 22’s PAC Display HMI software.
PC running PAC
Display Professional
Ethernet
switch
PC running PAC
Control Professional
SNAP PAC S-series controller
controls all I/O units.
I/O units are connected via a 2-wire RS-485 serial network and are
running the
mistic
protocol. Each I/O unit is connected to its own
group of sensors and actuators, and all I/O units are controlled by the
SNAP PAC S-series controller.
RS-485 serial
network
Sensors and actuators,
location #1
Sensors and actuators,
location #2
Sensors and actuators,
location #3