Many automation engineers are coming face to face with real fieldbus applications for the first time. Fieldbus (the use of digital communications networks for distributed instrumentation and control) is a wonderful technology with many benefits, but its installation requires some additional considerations over and above normal 4-20mA projects. This white paper discusses some of these issues, including choosing a fieldbus, power supplies, segment calculations, terminators, fieldbus cable and wiring, redundant operations, fieldbus in hazardous areas and intrinsically safe systems. The paper is free, but registration is required. The direct link is at http://tinyurl.com/bt6smhl.
FOUNDATION FIELDBUS IN 12 PARTS
Terry Blevins, Tom Kinney and Marcos Peluso have prepared this 12-part introduction to Foundation fieldbus. The subjects covered include an overview and basic concepts, justifying fieldbus use, the physical layer, fieldbus standards, the communications stack, function blocks, diagnostics, EDDL, high-speed Ethernet, advanced functionality and commissioning. The link to the blog post with links to all 12 parts is at http://tinyurl.com/cec5j7z.
Modeling and Control
FIELDBUS WIRING GUIDE
This guide provides information about the fieldbus network, so that its wiring system can be designed and installed for cost-effective and reliable operation. There are many uses for fieldbus and many ways it can be configured. It's not possible to give simple wiring rules that cover all cases. Therefore, this guides explain how fieldbus works, so the wiring system can be designed to achieve the best performance and most reliable operation with the lowest cost. It covers configuration, cabling, signals, connections, power, reliability, fieldbus limitations and more. This is a free download. The direct link is at http://tinyurl.com/cwbsnqj.
SPECIFYING FIELDBUS NETWORKS
An important trend in factory automation is the continual increase in networked interconnection between sensors, controls, actuators and other system components. Automation designers face many challenges and tradeoffs in the development of a successful network solution. This paper discusses the necessary choices in selecting a network technology appropriate for various specific applications, the technical constraints of several common fieldbuses, and guidelines for selecting media and protocols. This free download is found at http://tinyurl.com/c4um3lr.
Any fieldbus expert will tell you that the vast majority of problems experienced with a fieldbus installation are related to the physical layer. Things like wiring, connectors, terminators, power conditioners, and device couplers can be a smoothly running parts of your installation or a problem. This series of videos by Talon Petty of the Fieldbus Foundation covers best practices in fieldbus wiring. One of the topics is armor-plated wiring, which offers an extra hardened solution for environments that require it. If you work in a plant near the ocean, for example, you are quite familiar with the corrosive effects of salt air and storm-related flooding. Sometimes, opting for cable with a little extra protection is the right way to go, but there are a few things to keep in mind if you want to make it easy to deal with the armor jacketing. Check out these videos for some good pointers. The videos are free. Go to http://tinyurl.com/dyxhybc to download the video.
TUTORIALS AND COMPARISON CHARTS
This site contains a brief basic tutorial on fieldbus and two free, downloadable PDF comparison charts of some of the major fieldbus systems; Foundation fieldbus, Profibus, DeviceNet, AS-I, FMS, Modbus and HART. Go to www.pacontrol.com/Fieldbus.html for all three.
EAAL PROFIBUS TUTORIAL
This brief overview of Profibus helps users understand the interfacing of fieldbus I/O to the Cimetrix Open Development Environment's (CODE) control processes by using a device driver for a Profibus-DP I/O interface card. The direct link is at http://tinyurl.com/7cl3f57.