SNAP PAC Brains User’s Guide
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Chapter 3
3: System Architecture
This chapter explains how to use SNAP PAC brains in an Ethernet network and how to communicate
with them. It includes information on:
Communication Options
SNAP PAC brains communicate using TCP/IP or UDP/IP over a wired or wireless network.
Physical Layer
—SNAP PAC brains communicate over a 10- or 100-Mbps wired Ethernet link.
Transport Layer
—The key to the SNAP PAC brain‘s communication flexibility is the transport layer,
Internet Protocol (IP). Both the Transmission Control Protocol (TCP) and the User Datagram Protocol
(UDP) are used with IP.
Application Layer
—Because SNAP PAC brains use standard IP for the transport layer, many
communication options are possible in the application layer. After the I/O unit is installed and has an
IP address assigned (see
), you can communicate with it using the following methods:
•
PAC Control
strategies running on a SNAP PAC controller can configure, read, and write to I/O
points on SNAP PAC brains.
•
PAC Manager
software, in addition to its use for assigning IP addresses, can also be used to
configure I/O points and features, and perform onetime reads and writes.
•
Modbus/TCP
provides a direct connection with Modbus/TCP hardware or software or
third-party software applications, which can read or write to I/O points on SNAP PAC brains.
•
OPC
(OLE for Process Control) uses OptoOPCServer to serve data to any OPC 2.0-compliant
application, such as an HMI, which can also read or write to I/O points. OptoOPCServer can be
purchased separately or as part of the PAC Project Professional software suite.
Communication options
See below
System architecture
See
Networking
See
Specifications and feature comparison charts
See
