The simplicity of the analog meter, along with its low manufacturing cost, has been offset by its unreliability, inaccuracy, fragility, and subjective interpretation. The developer of its challenger, who has several patents on loop & signal powered technology claims that his latest invention of a “Solid State Analog Meter,” (SSAM, patent pending) would help prevent tragedies like those caused by traditional analog meters. Advances in LED technology, coupled with market challenges like cyber-security protection in the nuclear power industry, helped to motivate the Dr. Fest to not only create a substitute for unreliable analog meters, but to offer a 100% compatible replacement which accepts all standard industry input signals. The SSAM technology accepts all legacy signal inputs, including 4-20& 10-50 mA current loops, ACV, Watts, Hertz and DC Volts, Amps, and Watts. In fact, SSAM can be powered by any the signal that can provide >5 mW of energy to power it, even if no other power or current is available. It can also be externally powered from 3-32Vdc or 90-265 Vac.
To expand the applications of the SSAM, Otek’s Eng. staff has included other patented options which enhance the use of the new technology. These are loop: 1) Hi-Low alarms (Pat. #6, 285,094); 2) Loop Isolator (#7, 477,080); 3) 4-20 mA isolated retransmission (#7, 684, 768); 4) Signal Failure Detection& Alarm (#9, 054, 725); 5) AC Volts, Amps, Watts and Hertz Signal Powered options (#7, 626, 378), as well as isolated USB serial output (patent pending). The SSAM technology is the culmination of his 40 year love affair with the current loop. Dr. Fest created the industry’s first loop powered digital panel meter (DPM) back in 1974 and has been expanding on it ever since.
Why the obsession with replacing the old faithful analog meter, which was invented by Dr. Edward Weston in 1893? Read the inventor’s answer in his own words below.
As much as I admire Sir Weston’s invention of the analog panel meter (APM) and the fact that it has survived for over 120 years in use and popularity, it is important for me to challenge its legacy. So many tragedies have been blamed on the analog meter because of its tendency toward stuck needles, inaccuracies, and erroneous readings by operators. In addition, its inherent inaccuracy has caused many industries like the military and nuclear power to adopt a precautionary ~5-10% safety factor on all readings. Most APMs have an accuracy of only +/- 5% (+/- 2% if you are looking at it straight on from a distance of +/- 10 inches), plus parallax when interpreting the meter. The result is that a typical nuclear electric power plant could lose over $100,000 of saleable power daily because of this safety factor. We can and must do better after over 120 years!
Yes, the greatest technical and cleanest electrical power of mankind relies on a 19th century metering technology (D’Arsonval movement) perfected in 1893 by Dr. E. Weston! That’s the reason I rose to the occasion when I was challenged by a nuclear plant manager to develop an electronic bar-digital meter identical to our New Technology Meter (NTM) but without a microprocessor.
Why without a microprocessor?
Nuclear power plant I & C (Instrument & Control) rooms have to comply with Nuclear Regulatory Commission (NRC) cyber-security regulations (NEI08-09 and many others) if they digitize their I & C. This may cost them millions of dollars and years of implementation. In the meantime, if they keep their +/- 5% analog meters, they have to operate at below optimum in the most extreme case efficiency (+safety margin), losing 8-10% of their optimum electric power output. This translates into a real loss of about $100,000 per day for a typical reactor that produces about $1,000,000/day of electricity!
After being presented with this challenge by my customer, I kept asking myself, “How in the (H) world can I design all the features of the NTM without a microprocessor (digital asset) to avoid cyber security requirements & expenses?” Suddenly I remembered that back in 2004 I had experimented with a hardware-only (no microprocessor) bar graph-digital meter. So I went into a hunting frenzy, looking for my notebook of 2004 and the prototype breadboard of what I code named “3914.” After blowing the dust off the notebook and the meter, I applied 4-20 mA of power and voila! It lit up. However, it wasn’t fully working. Two weeks later I made it work as expected! A multicolor bar-digital meter solely powered by the 4-20 mA (~5-60 mW) current loop without a microprocessor!
Although this would have been enough to satisfy the plant manager’s challenge, it did not meet my own challenge of replacing the 1893 invention by Dr. Edward Weston with a 100% comparable digital! So I gathered all my patents related to loop and signal power (as listed above) and ended up with a new breed of LED electronic meters that will measure, display, control, and transmit AC and/or DC signals without a microprocessor, and all with a +/-0.5% digital accuracy!
The new microprocessor-less & Powerless TM meter series, named SSAM (Solid State Analog Meter) can be used as a basic bar graph (like the analog meter), as a bar-digital (like obsolete digitals), or as a multi-function meter field configurable (no programming) by the user. This multi-functionality reduces inventory cost because if the housing is the same, all you need to do is change the scale plate, pluggable modules and calibration (if required). That’s all!
Custom Display Colors? Because the SSAM has no uP, readout colors are done with high- efficiency, pure white LEDs whose colors can be customized by simply adding colored filters embedded in the scale plate at the user’s facility. After my Power Point presentation and demonstration of the new powerless technology at a nuclear corporate “Lunch & Learn” session, a manager asked me: “~What would you do if you were the I&C manager?”
I responded: Let me ask you: what is the simplest, most reliable & efficient means of transmitting analog signals? The Current Loop someone in the back yelled! Yes! If I had the wire & EMF, I could transmit an analog signal (and a digital over it as well [HART]) to the moon and back! So the first thing I would do is to decide whether to a) replace only the analog meters, or b) to add a DAS (Data Acquisition System), or c) add a state of the art SCADA (Supervisory Control and Data Acquisition System) with Triple Redundant Control TRC (such as our model TRC).
However, both b & c require Cyber-Security compliance. Option a does not have to comply with cyber security requirements, as the new SSAM doesn’t have microcontrollers or serial I/O! For the analog meter replacement only, I would: 1) Change all my signals & wiring to 4-20mA; 2): install the best 4-20mA transmitters, (hopefully our own NTT series), and 3) install the SSAM. With its easy wire-per-wire and panel compatible drop in ability, even existing wiring and panels can be reused with SSAM!
All other sections of the control room could remain the same, except that now your efficiency, daily productivity and profits would increase. A typical reactor produces about $1million daily of electric power, so every 1% increase in productivity is ~$10,000 per day of profit or ~$3.65 million/year!
All of above is explained & analyzed in my upcoming white paper entitled “Nuclear Reactor Efficiency and ROI Assessment.” It is further explained in my response to the Nuclear News June 2017 editorial by INL Engineers titled “Human Factors for Main Control Room Modernization.” In this article, I identify and analyze 6 options for the digitalization of I &C rooms:
1) Do nothing and keep the current analog or digital instruments and lose ~$10K/day, or $3.65 million/year, for every 1% loss in efficiency in a ~$1M/day plant!
2) Go for broke with flat screens & SCADA Triple Redundancy Control and comply with cyber- security regulations at over $200 million and 5-7 years of implementation time. This translates to a loss of >$10K/day or 1% of profits for 5-7 years. Add to this cost the investment price tag of ~$200 million (+ overruns) and you’ll lose over $300 million!
3) Change to flat screens & DAS (for data collection only). You still incur cyber security compliance costs of about $75 million and the loss of 1% per day of income while you wait for the upgrade. The potential loss could be over $150 million in the process.
4) Replace (during outage) obsolete meters with Otek’s NTM series, which are SCADA/DAS/DCS compatible (like option 1) Class1E instead of flat screens. This option means no new wiring (except serial I/O), no power supply and no new building costs. This saves about $75 million but adds cyber security compliance costs (~$20 million?); it eliminates the 5-7 years of loss profits while waiting for a new building. The return on investment (ROI) will take only about 18 months (assuming a 10% increase in efficiency or ~$36.5 million/year!)
5) Implement a DAS (Data Acquisition System [data collection & analysis]) with Otek’s NTM series (or equivalent) during one outage. This is equivalent to option #3, but at its lower cost of about $35 million and with no loss of normal productivity & no new building to build & wait. This ROI is about one (1) year for a typical 5-8 % increase in efficiency including cyber security cost!
6) If you are a non-regulated utility or your reactor has a limited operating life expectancy or is in a very competitive market, just replace your obsolete analog & digitals all at once or as needed with the SSAM series. The total cost would be about 1/3 of replacing the obsolete analog/ digitals, and will pay for itself within the first week (assuming a 1% increase in efficiency)! And the rest is profit for years to come!
Conclusion: After over 40 years of persistency, I feel I have done justice to the long lived analog meter of 1893! Thank you Dr. Edward Weston for an excellent job well done! But all good things must come to an end! I still think that the analog meter is near extinction!
Dr. Otto P. Fest,
resident/Founder of Otek Corporation