With regard to July's problem about networked switches ("Time for a Sensor Network?", July '11, www.ControlDesign.com/real0711): I work as controls engineer for a machine builder/system integrator. The worst part about making the upgrade is getting rid of the old stuff. I’ve performed many upgrades from hardwired I/O to DeviceNet, Ethernet, remote I/O and other protocols. In my experience, the DeviceNet and Ethernet protocols are pretty simple, and have a faster response time. Though it might take maintenance a little while to get the hang of how the networks work, in the end it will definitely save tons of downtime, troubleshooting and wiring headaches.
Chris Wright, Controls Engineer,
Commonwealth Tool & Machine,
www.commonwealthtool.com
