Overview

Whzan is a uniquely simple and versatile way to use the web to observe and control the status of remote equipment.

One of the ways Whzan can be used in the industrial environment is to connect to 'Modbus' capable devices.  Through this link, it is possible to exchange data to the industrial control device and bring it onto web based graphical displays for access, from anywhere.

There are hundreds of programmable logic controller (PLC) manufacturers.  Each have their own merits and specialities, but most can communicate via the Modbus protocol.  PLCs are ideal for automation of repetitive sequences and for producing predetermined responses to multiple inputs.  PLC capabilities range from just a few inputs and outputs to systems with thousands of I/O functions.  PLCs have processors and run through a repetitive cycle of checking inputs, determining the appropriate responses and setting outputs.

In this example, we have chosen a small robust PLC well suited to small to medium size applications.  It is the Crouzet Millenium 3.  This is easy to program and has an Ethernet connection option (Part No. XN05) which we will utilize for communications.

Crouzet with network interface

The Crouzet Millenium 3 has a programming tool that will work in ladder logic or in a functional block diagram mode.  The Ethernet data is available as 16-bit integers on 8 inputs and 8 outputs.  Whzan can exchange data with these 16 I/O points.