Tuesday, 23 July 2019
A 1°F Error In Measurement Can Cost You $15,000 Per Year

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The quality of the instruments and the equipment you’re using can have a major impact on your company’s finances. Therefore, the accuracy and precision of your sensors’ measurements are key quality factors to look for when it comes to purchasing instrumentation.

When monitoring heat, for example, a 1°F error from your measurement system could be costing your company thousands of dollars every year. What if you could cut $15K in spending annually with minimal effort?

Quick Definition Review

Accuracy, Precision and Resolution:

Although these two terms are often used interchangeably, in the test and measurement industry, accuracy and precision are two of the main factors that come into play when evaluating a sensor’s quality.

Accuracy refers to how close the measurements are to the true value while precision refers to how close measurements are to each other.

On the other hand, resolution is the smallest number than can be indicated or recorded by an instrument.

In short, accuracy is a combination of precision, resolution and calibration. As we will see in the following case study, a slight error in accuracy caused by an uncalibrated sensor can have a significant impact on a system’s overall performance.  

Accurate target 

Typical Case Study

Here’s a typical example of a problem you may encounter:

Water is used for heating, flowing at a rate of 100 gallons per minute (GPM) for a year. The water is to be controlled at 100°F, but due to the monitoring sensors’ inaccuracy, it’s actually being controlled at 101°F. How much heat is used to raise the temperature of a year’s worth of fluid by 1°F and how much does that energy cost?

Q=cpm (delta T) Where:

Q = heat transferred (BTU)

cp = specific heat at constant pressure (BTU/lbm-°F)

m = mass (lbm)

(delta T) = temperature change (°F)

cp = 1 BTU/lbm-°F

m = (8.33 lbm/gal)(100gal/min)(525600min/yr) = 437,824,800 lbm/yr

(delta T) = 1 °F

Solving: Q = 437,824,800 BTU = 128,282 KW-hour

For an electrically heated system:

Assuming the cost of electricity is 12 cents per KW-hour.

Cost = (128,282 KW-hour)(0.12 dollars/KW-hour) =

$15,393.84/year from a 1°F error

 

How You Can Avoid This Situation

As you can see, a small error can end up costing a lot of money.

The first step to avoid these situations is to choose a high quality sensor that matches the requirements of your application. When it comes to instrumentation design, the most fundamental aspect is eliminating or minimizing variables that cause inaccurate measurements. Making sure that you choose a sensor that is adapted to the environment in which it will be used — i.e. indoor, outdoor, in contact with water or corrosive substances, etc. — and that it is properly installed are two of the many elements to take into consideration.  

The second step to ensure that the accuracy and precision of your device is regular maintenance through calibration. Calibration is the process of configuring an instrument to provide a result for a sample within an acceptable range. It is typically performed to determine the error or verify the accuracy of the device under test’s unknown value.

The frequency at which your instruments should be calibrated varies depending on the manufacturer, the type of instrument and what it’s used for. A general recommendation is to have them recalibrated once a year, though your manufacturer may suggest otherwise.

Want to find out more about calibration? Check out our demo videos on our YouTube channel for Float level sensor calibration, Pressure sensor calibration and Capacitive level calibration.

Thursday, 06 October 2016
Intempco’s MIST : Big Idea, Small Design

A little history

In 2001, a temperature transmitter with a miniature packaging and an integrated design arrived  on the market. Although quite accurate, the transmitter was non-scalable, non-programmable and impossible to calibrate, which made it a poor performance instrument.

Despite its flaws, Intempco saw the potential of this type of compact design and how it could be useful in a variety of industries. It was enough to inspire us to start working on a prototype that would later become the MIST, the Microprocessor Integrated Sensor Transmitter .

Our objective was to create a transmitter with an integrated electronic circuit and microprocessor that could be re-calibrated and re-scaled over its entire range of operation. We wanted it to be small and easy to install, but also robust and long lasting.

This proved to be an ambitious project that we were able to complete with great success. Eight years of R&D led us to finally obtaining a patent for the MIST in 2010.

The first markets to be attracted to this type of product were the food and pharmaceutical industries. Today, the MIST has been adopted for temperature measurement in a wide range of industries including refineries as well as chemical and petrochemical plants. Industrial companies and OEMs across Canada and the United States also recognize the added value of this type of solution. 

Intempco's MIST 03

The final product

The end result of our R&D efforts was a transmitter that is hermetically sealed in a stainless steel housing less than 2.5 inches long. Its extremely small size makes the MIST ideal for any application where limited space does not allow the use of a connection head, such as compressors, generators, chillers, engines and other general industrial applications. Also, the MIST combines the stability and accuracy of an RTD element with the benefits of an integral 4 to 20mA signal-conditioning device. 

What makes this product so innovative, is that it can be re-calibrated and re-scaled over its entire range of operation via the optional digital communication link and the accompanying user-friendly MIST software, thus dispensing with costly factory re-calibration.

Our tests also revealed that the MIST was far more accurate than the conventional sensor and transmitter combinations because it comes factory calibrated to a customer specified temperature range. Its accuracy is stable over its entire measuring scale, which is well above industry standards (-200 to 600 ̊C). With the optional Communication Kit, accuracy can be greatly increased by performing one-point or two-point calibration using known temperature standards. 

The MIST Series is the result of years and years of R&D, design, legal work and so on. The driving force behind all of our efforts in creating the MIST was to design a sturdy and highly accurate temperature transmitter that offered the best solution to our customers who needed a small packaging.

To find out more about the MIST Series and other temperature measurement solutions, visit our Products section.