Control Units
A controller and its smart I/O modules collectively are referred to as a control unit. Each control unit has the capability to automate its control tasks and log local data. In addition, any control unit is accessible through the LAN using a PC. Each PC may monitor and control the units, log their data, update web pages with information collected from the units, or generate e-mail messages containing data collected from the units. Being on the LAN, any PC may access any control unit, provided that the security criteria (e.g. passwords) are met.