CHAPTER 1: OVERVIEW
SNAP PAC S-Series User’s Guide
9
9
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
