Let's start with accuracy vs. resolution, then move on to the cost of cheapness.

Many people are confused by the difference between resolution and accuracy. Including some manufacturers and re-marketers who should know better.

What is the difference? Let us make a sporting analogy.

You have two rifles – a high quality one and a low quality one. The high quality one is manufactured to shoot with a small “spread” – in other words, several bullets fired from the high-quality rifle will land within a small distance of each other, perhaps within a 1” circle. The low quality rifle will have a larger “spread” – for example, a 10” diameter area within which rounds that are fired at a single target will land.

Obviously, it’s easier to tell where a bullet from the high quality rifle was supposed to land. Using the high quality rifle, you can distinguish targets as close as an inch or two apart. The low quality rifle, with its larger “spread”, would generate a scatter of shots over the whole area being targeted.

The high quality rifle has high resolution. It can be aimed at targets only a small distance apart. The low quality rifle has low resolution. It can be used for firing at the general area of a target, but if you need to distinguish between separate small targets it won’t do the job.

Let’s move on to accuracy.

Imagine a three-inch-wide target. Imagine that the high-quality rifle is aimed six inches or so to the right of the target. Because of its small spread, it will never hit the target. The rifle can then be said to have high resolution but poor accuracy. If aimed directly at the target, it will hit it every time; it then has high resolution and good accuracy.

Now here’s an interesting thought! Aim the low quality rifle six inches to the right of the target, and it will occasionally hit the target -because of its low resolution. This is the approach taken to instrumentation by most manufacturers, alas. You will find plenty of examples in scientific equipment and teaching catalogs.

What does this have to do with gas analyzers? Let’s look at the resolution question, and other factors to consider when choosing a gas analyzer. You might be surprised at what you learn.

1. Resolution isn’t accuracy.

Some years ago a competitor started to exhibit at scientific meetings, claiming that their oxygen analyzers delivered 0.001% accuracy. However, a manufacturer that claims 0.001% accuracy for a gas analyzer is, in our opinion as instrumentation experts, not being – if you will excuse the term – accurate. The variations introduced by varying furnace temperatures, analog antilogarithmic circuitry, span gas accuracy, and other factors in their analyzers absolutely prohibit this level of accuracy, but they don’t completely prohibit this level of resolution. Of course, you need to have a technical and scientific rather than a sales and financial background to appreciate this distinction. But wouldn’t it be nice to deal with a firm, such as ours, that knows the difference?

Our analyzers have 0.001% resolution, or better. Their accuracy is favorably comparable to the best on the market – typically 0.1% or better for oxygen, or 1% or better for carbon dioxide. Regarding the latter figure: In conversation with NIST, we have determined that the very best possible calibration for a practical CO2 analyzer, using NIST's own impeccable standard gases, would be 0.3 - 0.5% of full scale. Any firm claiming a better figure is being, shall we say, inventive. We understand what we make and what we sell, and will never intentionally mislead you.

After reading this piece (we have to assume), one of our competitors actually had their booth signs for their oxygen analyzers re-made to reflect a claimed accuracy of 0.01%, a ten-fold reduction of their previous claim. We smiled indulgently, knowing that a critical non-linear component in their analyzers prohibits that level of accuracy, too. We know all about that component because of our intimate knowledge of the inner workings of that analyzer dating back from 1983, long before the present owners bought the rights to it. If they ask us, we'll be happy to tell them what that component is. To date they remain in happy ignorance.

2. Research isn’t teaching, and cheapness can be expensive.

We produce high-quality equipment that can be used for research or teaching. Certain firms are marketing super-cheap gas analyzers and accessories, in order to provide cost-conscious teachers with equipment for use in low-budget teaching laboratories. Some of these analyzers, in fancier cases, are being aggressively re-marketed as research analyzers. Dealing with these firms is dangerous, as we'll see below.

But first, how to recognize them. You can recognize these firms in three ways, two easy and the third more difficult. The first and easiest way to recognize them is by their emphasis on cheapness. The second is by their exaggerated, almost drunken claims of being the "best" while their specifications (if they give any) contradict them, at least to anyone familiar with our products. They will claim to have the best equipment and the lowest price, and are quite correct on their latter claim. As for their former claim, well, it links to the third way to recognize these firms. In a word or two, it's street cred. After the joy of getting a bargain wears off a new buyer and the low quality, drift, lack of reliability, and atrocious tehnical support start to wear on her, she'll ask around and quickly find that her experience was typical. Then she hears about Sable Systems' street cred, and feels rather foolish about purchasing research equipment based on price rather than quality. We speak to many people in that category and help them, where we can, to get back on their feet again and start over. Some of our best customers were exposed to this caliber of equipment early on and later swore never to have anything to do with the firms concerned.

So, you will need to use your judgment when using these toy “teaching analyzers” and other toy teaching tools, however deliciously cheap they are. These simple, marginally stable and very slowly responding carbon dioxide analyzers are based on pre-made modules designed solely to alert building occupants when CO2 concentrations rise to unhealthy levels. They were never designed to be used as gas analyzers in a teaching, let alone research, setting. The module's actual manufacturer rates their accuracy at 50 ppm, or about 15% at atmospheric levels. You can recognize such analyzers, even if they've been moved into fancier cases and may be selling for thousands of dollars in an attempt to attract researchers, by their slow response times, necessitated by the massive averaging required to produce a nominally stable signal from them. Watch out for response times longer than one or two seconds in carbon dioxide analyzers - they are a nearly infallible indicator of poor quality. Whatever assurances you may receive, such toy analyzers are not intended for or suitable for research.

For low-budget teaching, they may be adequate. But your reputation will suffer if you publish research results in a reputable journal, citing one of these sick building "analyzers", and a paper is subsequently published invalidating the inflated claims of the toy "analyzer's" re-packager.

A firm's commitment to quality is evident not only in the equipment it sells (or re-sells), but in the advice it gives to prospective customers. We are alarmed by the statements of our competitors and imitators at exhibit booths at scientific meetings.

We have heard, or had repeated to us by reliable witnesses, many gems. We bring them to your notice not to thumb our noses at our imitators, but as a service to you - because you need to know whether you are dealing with firms that are honest with you, and can therefore sell you honestly-specified instruments that will allow you to do honest, reproducable science. The "gems" include:

• The claimed ability of a differential gas analyzer with a 10 ppm peak-to-peak noise level, to measure the gas exchange of a single Drosophila (which, at 0.5 ppm at typical flow rates, is actually buried twenty-fold below the instrument's noise floor.)
• A low-resolution "toy" voltage measuring interface that its actual manufacturer states is not suitable for research, is re-marketed by a certain firm and touted as a research tool that can be cited in research papers. (The author of such a paper may have to retract it if he or she follows these exhibitors' advice.) Searching Google Scholar for the name of this avowedly non-research-grade interface brings up quite a few hits in the literature from gullible scientists who believed what a certain firm told them and probably have no idea of their potential predicament.
• A fuel cell wrapped in aluminum foil and attached to a cheap preamplifier, hooked up to said low-resolution interface designed exclusively for teaching, is touted as giving performance equivalent to a Sable Systems oxygen analyzer. (This is like comparing the race-track performance of a steerable lawnmower to that of a Ferrari.)
• A CO2 analyzer's "accuracy" is cited at "0.02%" - whereas no carbon dioxide span gases of that accuracy are available to test the claim, the actual optical bench used in that analyzer has a rated accuracy of 1% at best, and the manufacturer says that "room air" should be used to "zero" the analyzer - room air at a CO2 concentration of 0.05 - 0.1%, which would ruin its claimed accuracy by severalfold!
• A firm selling oxygen analyzers claims that it sells components to Sable Systems that we use in our gas analyzers. What can we say? We make all of the sub-assemblies for our gas analyzers, including the infrared optical bench for sensing carbon dioxide levels. We use nothing made by the firm in question in our analyzers or anything else.

Allow us to quote Stephen Leacock: "[such] advertising may be described as the science of arresting human intelligence long enough to get money from it." Were these gems the product of ignorance or of something more sinister? Which would you prefer in a firm? With us, you'll get neither.

We have to admit that "toy" equipment is cheap (although some toy gas analyzers attain the veneer of quality by being way overpriced, considering their noise, drift and unreliability.) But imagine the real cost of cheapness. Perhaps the bitterness of retracting a paper or ruining a year of research, or a student's dissertation, because you used a data acquisition and analysis system designed for high schools and undergraduate education, and specifically not recommended, by its actual manufacturer, for use in research. How much is avoiding that fate worth to you? How much is believing in your own research worth to you?

Our instruments are honestly specified. They are not toys. For example, our data acquisition interfaces offer ten to fifty times the accuracy and twenty to a thousand times the resolution of many of our competitors' products. The essence of research is replicability! So, even if we wanted to fool you, which we don't, we're smart enough to know that in the long run we can't fool you. You can use our instruments and interfaces in the most demanding research applications with total confidence.

Don't get us wrong; for undergraduate teaching in really cash-strapped colleges, super-cheap toy instruments unsuitable for research may have their place. But they don't have a place in the lab of any self-respecting scientist practicing replicable research. And lying about the suitability of products for their intended application, as our less reputable competitors and imitators do, is not only morally reprehensible. It is against the law.

We take research very seriously. Research adds to the knowledge base of our species. It's not a fitting place for shill-fests.

Issuing such warnings is what the First Amendment of the United States Constitution is all about. And the First Amendment is central to the Electronic Frontier Foundation, an organization of which we are privileged to be a member.

3. How firm is the firm?

Sable Systems International was founded in 1987 and enjoys a remarkable record of success and reliability – both in the fields of instrumentation and software, and the all-important field of customer satisfaction.

We go to extraordinary lengths to keep our customers happy, well-informed and secure in the knowledge that they’re not dealing with a fly-by-night or amateurish, imitative instructor/workfare operation. We don't imitate; we innovate. We’ve been consistent in that policy for over two decades, and we offer first-rate technical assistance from real experts.

Sable Systems International is here for the long haul. We make products that we are proud of. We use the very best components and materials, and charge the lowest price we can while ensuring high quality, and the long-term survival of our business, which is very much in your interest. We are absolutely honest with you. You will never regret purchasing any of our products, period. That’s an ironclad promise.

Throughout the world, scientists in academia and industry have learned to trust Sable Systems International. Our equipment is specified in all seven continents including Antarctica (and in orbit), by leading researchers, by National Academy members and Nobel Prize winners. Leading scientists trust their reputation to the performance of our equipment, in top peer-reviewed journals such as Nature, Science, PNAS and others. Established over two decades ago, a business founded by scientists for scientists, we understand and respect your unique requirements. We will never mislead you. And you will enjoy doing business with us.

Whatever instrument you purchase from Sable Systems International, be assured that you will acquire a fine product, and our complete commitment to making your experience a positive and rewarding one.

And who else can say that, and mean it, and has the track record and street cred to prove it?