I thought the article, "Selecting the Right Industrial Network," [Control Engineering, January 1998, p. 61] was both interesting and useful. We are in the process of swimming through the variety of selections that are out there. This article was helpful! Thank you!Rick Tyson, electrical engineer, Salt Lake County Water Conservancy District, West Jordan, Ut.
As controls and automation become more distributed and integrated, industrial communication networks and buses are becoming more crucial because they link controls with real world, in-the-trench, manufacturing processes. However, due to growing choices of networks, protocols, buses, and node connections, it is helpful to understand the basic aspects of each network or bus before picking an overall architecture. Physical topologies include linear buses (with drops), and daisy-chained, ring (where all nodes are connected in a physical ring), star, and mixed types. Each has its own advantages and drawbacks. Bus arbitration schemes include master-slave and peer-to-peer (CSMA or collision sense/multi-access, and token-passing).
Charlotte, N.C. —DIO PC control PC for networked control systems features either 386/486 or 586 microprocessor with RAM and Flash memory. The solid-state unit contains an integrated L-Bus port for local analog and digital I/O modules. Other features include 24 V dc power input, two com ports, one LPT port, and an Ethernet port.