New approaches for remote I/O installations


<< First < Previous 1 2 Next > Last >>

Jonas , , 08/10/13 02:10 AM:

In principle I personally think we should move beyond conventional hardwired signals like 4-20 mA and different kinds of on/off signals, also for the “first meter” between the sensor/actuator and junction box.. The system shall be networked with digital communication all the way down to sensors and actuators like transmitters and positioners. That is, the first meter from junction box to individual instruments shall also be real-time digital communication. In other words, digital closed loop control from sensor to actuator, from field to control room. Instead of running multiple conventional signal wires per device (2 or 3 signals per control valve or on/off valve, maybe 6-12 signals per electric actuator, 2 or 3 per level and flow transmitter) you instead just branch out a fieldbus trunk cable from the junction box to each device, handling all signals in that device. 5,000 conventional I/O points becomes 1,700 fieldbus devices

By fieldbussing the I/O, you don’t need enlarged I/O enclosures in the field and need not put any I/O cards in the harsh field environment. Instead of system cards in large field cabinets, you retain small simple passive field junction boxes suitable for zone 2 or 1. There is no need to send system technicians to the field for service on I/O cards.
Each bus is designed for 10 devices but can be expanded up to 12, 14, or even 16 devices. Additional signals for each device such as feedback can be added in devices without using I/O channels
It doesn’t matter if a device is a sensor or actuator, regulator or discrete in nature, because the fieldbus interface card and safety barrier is the same, so device types can change late in the project without requiring redesign. Cross-wiring is eliminated
Fieldbus also lends itself well to this concept. See for instance this FPSO:
Fieldbus on mammoth modular construction on-shore projects is also done. For instance this Alumina plant:
Fieldbus is also ideal for those "nice to have features". You can access all those 12-16 signals in an electric actuator / motor operated valve (MOV) or other devices.
I personally believe signals should be digital all the way; no 4-20 mA or on/off signals, like many plants already do with fieldbus. Transmitters are digital, controllers are digital, and positioners are digital, why should they have an analog signal between them? Some vibrating fork level switches and on/off valves now have intelligence, why should there be an on/off signal to isolate them from the rest of the digital nervous system that cover the plant. Only with fieldbus can we say we have real-time “communication with field instrumentation and devices” and a truly “digital plant”. Cameras are digital, phones are digital, mail is digital, music is digital, video is digital, and TV is digital etc. Process control should also be digital such that more plants can reap the benefits of digital.
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
Each year, a panel of Control Engineering editors and industry expert judges select the System Integrator of the Year Award winners.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Learn how to create value with re-use; gain productivity with lean automation and connectivity, and optimize panel design and construction.
Go deep: Automation tackles offshore oil challenges; Ethernet advice; Wireless robotics; Product exclusives; Digital edition exclusives
Lost in the gray scale? How to get effective HMIs; Best practices: Integrate old and new wireless systems; Smart software, networks; Service provider certifications
Fixing PID: Part 2: Tweaking controller strategy; Machine safety networks; Salary survey and career advice; Smart I/O architecture; Product exclusives
The Ask Control Engineering blog covers all aspects of automation, including motors, drives, sensors, motion control, machine control, and embedded systems.
Look at the basics of industrial wireless technologies, wireless concepts, wireless standards, and wireless best practices with Daniel E. Capano of Diversified Technical Services Inc.
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
This is a blog from the trenches – written by engineers who are implementing and upgrading control systems every day across every industry.
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Control Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.