User`s manual

Watlow Controls Communications Guide 4
Chapter One -
Introduction
Audience
The document is targeted towards new
users interested in using data
communications with Watlow controllers.
Media
This document is available in electronic
format only. It is viewable using Adobe
Acrobat Reader available free from the
Adobe site www.adobe.com on the
World Wide Web.
Purpose
The purpose of this document is to enable
users to:
1. Understand the basics of serial data
communications via standard
definitions, interfaces and protocols.
2. Set up and use a simple network of one
Watlow controller.
3. Set up and use a network of two or
more Watlow controllers with HMI
(human-machine interface) software
or an operator interface panel.
Getting Started
Your task is to get one or more controllers
to talk to a PC or PLC. How do you make
this happen? The purpose of this
document is to assist you in that task by
providing information about
communications. The task of getting a PC
or PLC communicating with controllers is
a five step process:
1. Determine a strategy for
communications.
2. Purchase a controller with a
communication interface and
protocol that supports your
strategy.
3. Wire controllers for power, control
and communication.
4. Configure the controllers to do
what you want them to do.
5. Configure the PC or PLC software
and hardware to do what you want
them to do.
The first step is the most difficult since
decisions need to be made before anything
is purchased. It really involves three basic
items:
1. Determine how many controllers
you will communicate with.
2. Pick a protocol and interface that
supports the information exchange.
3. Purchase hardware and software to
make this happen.
This document will only deal with the task
of communication. Refer to the user’s
manuals for each product for information
about wiring and configuring the
controllers and software.
Convention
In this document, numbers in the format
0x00 represent values in hexadecimal.
Numbers in the format 0 represent values
in decimal and finally, numbers in the
format 00000000 represent values in
binary unless stated otherwise.