Pneumatic signaling still wheezes?

Are instrumentation transmitters that use 3-15 psi analog signals still around?

04/08/2011


Dear Control Engineering: I was reading the article about using smart instrumentation, and it discusses some of the history of field devices, back when everything ran on pneumatic systems. Are pneumatic analog devices still around?

Pneumatic devices have been gone for the most part for quite a while, with the majority replaced by the 1980s. Of course their demise was not all in one fell swoop. The move to electronic analog and digital devices took some time and is probably still not entirely complete. Process instrumentation and control devices like valves, that operate on 3-15 psi are certainly still around, but you will have to hunt for them.

After a few minutes digging around the industrial listings on eBay, I managed to find an old Foxboro liquid level transmitter 13FA1-HK31A5 sold by a company called National Recycling. That should tell you something.

There are companies that still sell new 3-15 psi transmitters, but these are rare too. Here’s a company in Italy that still offers a small selection. There are certainly others if you care to look more thoroughly. More often than not, the pneumatic devices available now are converters that change pneumatic to electronic. Here’s one that changes a Foundation fieldbus signal to pneumatic for a control valve.

Suffice it to say, small delicate mechanisms with diaphragms and leak-prone tubing were not exactly maintenance friendly, so I doubt very many people were sad over the change to electronics. As the article points out, compressed air signals can’t convey much information. An air signal line is good for one signal and that’s it. No diagnostic data, no secondary variables, it’s pretty dumb.

Granted there are still folks out there that want to see trains pulled by steam locomotives, cars with carburetors, and their newspapers set on Linotypes, but the romance of such things gets eclipsed quickly when one has to deal with how maintenance intensive those older technologies are.

If you still use pneumatics and are proud of it, let us know.

Peter Welander, pwelander@cfemedia.com



No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
2015 Top Plant: Phoenix Contact, Middletown, Pa.; 2015 Best Practices: Automation, Electrical Safety, Electrical Systems, Pneumatics, Material Handling, Mechanical Systems
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Raising the standard: What's new with NFPA 70E; A global view of manufacturing; Maintenance data; Fit bearings properly
Special report: U.S. natural gas; LNG transport technologies evolve to meet market demand; Understanding new methane regulations; Predictive maintenance for gas pipeline compressors
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Migrating industrial networks; Tracking HMI advances; Making the right automation changes
Understanding transfer switch operation; Coordinating protective devices; Analyzing NEC 2014 changes; Cooling data centers
Upgrading secondary control systems; Keeping enclosures conditioned; Diagnostics increase equipment uptime; Mechatronics simplifies machine design

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role that compressed air plays in manufacturing plants.