Gary A. Mintchel, Control Engineering

Plan Ahead to Build the Perfect HMI System

Does this still sound familiar? A machine, packaging line, or other process is defined and mechanical designers charge ahead. When mechanical design is almost complete, I/O points are counted. The control engineer figures out what model PLC will handle the load and begins writing ladder logic. Now the project is running behind and someone says, "We need to throw a display in there for ope...

Power Up Programming with Graphical Modeling

First there was text-based programming with tools such as general editors/compilers like Basic or C, or Structured Text or Instruction List. Then graphic programming for control was adapted from Relay Ladder Diagrams, first on special programming terminals, and later on personal computers. Function block diagrams added another dimension to graphic representations of process control.