Automating Manufacturing Processes with Ethernet-Enabled I/O Modules, Linux - page 2
What's A PLC?
That's where Woodhead Connectivity in Northbrook, Illinois comes in. They've developed an Ethernet-enabled I/O module that can be mounted directly on a machine and controlled from any PC or PLC using standard ladder logic programming techniques. They also make industrial strength cabling, connectors and ruggedized ethernet switches that can also mount right on a machine. Their latest project used the I/O modules tied to a Linux box that was tasked with programming, monitoring and data collection. The basic discreet 8 input/output port Ethernet enabled module from Woodhead costs $350. Prototyping a new project with these I/O modules, Ethernet, Linux and some Open Source software seems like it would be feasible for just about anyone.
System integrator Centech Automation in Palatine, Illinois teamed up with Woodhead Connectivity to deliver an electropolishing line to one of Centech's industrial clients.
The system the team designed was an electropolishing line that used a motor driven lift arm on a moving gantry for parts transfer from processing tank to processing tank. The motor control and positioning of the system was controlled over ethernet using the Ethernet/IP control protocol. The sensing and actuation was controlled by a collection of proximity and limit switches, solenoids and motor drives through Woodhead Connectivity I/O modules located on the machine.
While other operating systems could have been used for the control computer, the team chose a Linux box running Red Hat 7.2, mainly due to cost and reliability factors. When you're delivering a $100,000 industrial system the components must be cost effective and rugged. Linux has proven to be easy to set up, stable and able to support remote administration. Since Linux is multi-user, technicians can log in to the box for reprogramming, maintanence or upgrading from just about any place that has an Ethernet connection.