Evolution is present everywhere in business. New ideas build upon old ideas and the lineage of any one invention can trace its roots through many products and practices. So too, the process historian is a tool that was invented as an improvement to do a better job than the previous tools. Today, computer savvy professionals in manufacturing management may not understand the basic functionality of a process historian. I invite you to read through this article to learn the background of the process historian and to remove some of the mystery and sales jargon that keep many professionals today from even understanding what they are buying.

Turn back the clock to 1982: No computers, no internet, you have a secretary that types memos and letters. After a two year project and a long startup, you are walking around your state-of-the-art powerhouse control room singing “Physical” by Olivia-Newton John to yourself. You survey the control room and see that the old bench board of pneumatic controllers is now replaced with a row of computer consoles like NASA’s mission control. Operators can see graphic representations of the process and control the boiler from the computer. The electronic controls are making the process run better than ever and real-time information is available in the office or maintenance shop – for about $100,000.00 for a console. But now you look beyond the consoles to see the old panel board of ink and paper chart recorders. Dang, you wish you could have replaced that mess but there is just not enough money in the company to replace our historical records with electronic records.

Fast forward to 1992: You have a 486 computer wedged under your desk, a 15 inch monitor and keyboard on your desk – and a sore neck every evening. You walk through the control room singing “I’m Too Sexy” by Right Said Fred to yourself and see that all of the ink charts are gone – replaced by a process historian. The operators have two new computers specifically to show trends that replace the ink and paper charts. The new process historian uses a proprietary controller interface and a sophisticated delta-slope storage algorithm to store the least amount of data on the server’s huge 500 MB hard drive. The historian proprietary trend tools will allow your people to call up the process variable and time in trend displays. The system is slick – not only does it allow you to replace the ink and paper recorders but you can see the real-time or historical trends on your 486 computer in the office!

Present: You have never had a secretary. You have a smoking laptop with a 120 GB HD connected to your docking port in your cubical where you spend too much time on FaceBook and reading Aston Kutcher’s latest tweets. You are walking to the conference room meeting concerning a new system for performance management and for some reason you can’t get the music video “Young Forever” by Jay-Z and Mr. Hudson out of your mind this morning. The company coming in to talk about a solution today has a solution called “Management System” or “SuperBad Platform” or something. You have some concerns but you know that IEEE has created standards for getting real-time data from any controller or historical data from any process historian.

Many companies need a good process historian and excellent trending and reporting tools to enable operators and engineers to improve the process performance. Companies with hybrid processes (some process control and discrete manufacturing) also need trending and lots of process data. But the process historian is still today a tool of recording a Process Variable and time and storing that data long-term for retrieval. Its fame is the speed of storage and compression but the process historian is for most purposes and facilities a commodity decision. The technical aspects are rate of storage and rate of retrieval. This is still an engineering decision to determine the rate of storage of data from the process needed for the application. IEEE standards like OPC-HDA and OPC-UA assure users that hundreds of independent software companies the world over will continue to write user tools and software packages for use with any historian.

In closing – it is important to state that the process historian will always be an important tool. But, the process historian may not be the best foundation for process improvement in industry. The historian was the electronic replacement for a strip chart recorder – it is a data source that needs an intelligence solution on top of it to analyze the data in order to make a decision. Process Intelligence systems – whether software or an operator – are independent of a process historian.

The process historian is a good tool – but if you need OEE, performance metrics, inventory control, genealogy or reporting – you will only use the historian as a source of data.


Kevin Totherow is a Business Development Manager of MES for Schneider Electric and a consultant for helping manufacturing clients manage their operations better. Kevin has been a controls engineer, consultant and president of Sylution Incorporated. He can be reached at (864) 252-6819 or by email at kevin.totherow@schneider-electric.com.

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