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Engineering Stack Exchange

Questions tagged [measurements]

Measurements, instrumentation, calibration and metrology.

Questions about measurement, instrumentation, calibration and metrology. Covers both automatic and manual measurement.

Also questions about conversions between measurement units, and official standards for engineering and scientific measurement.

See also the tag of metrology.

269 questions
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7 answers

How can I measure correctly with a ruler?

When measuring with a ruler divided into mm lines, should I include the lines by themselves or only in between them? I illustrated the problem. (I took an example of measuring of 10 mm with two long lines just to make my point, but my question is…
Ubiquitous Student
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9
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3 answers

What are grads used for on a scientific calculator?

Every scientific calculator I've come across has a DRG button that controls whether trigonometric functions use units of degrees, radians or grads yet I've never seen or heard of any system that actually uses grads. When is the grads setting useful?
cup
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7
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5 answers

Can redundancy be used instead of periodic calibration?

A lot of production equipment requires periodic calibration as part the documentation that the equipment is under control. The companies selling the equipment knows this and sometimes lowers the price of the equipment and offer an expensive service…
Norfeldt
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5
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1 answer

High-resolution Z stage distance measurement

I am designing a 3-stage platform like that of a 3D printer. Three stages correspond to X, Y, and Z axis. There is a nozzle with fixed height about the z-stage platform. The stages are pretty accurate with a resolution of 1 micron. Now I need to…
Jarvis Du
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4
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3 answers

How does a frequency to voltage converter work?

I am measuring the rotational speed of a shaft using a disk with 60 cuts and an optical fork. The signal from the optical fork is sent to a frequency to voltage converter and after that to a data acquisition system. What is the working principle of…
Razvan
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4
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2 answers

Is there a way to distinguish between U.S. Customary and British Imperial volumetric units?

I am used to the metric system where everything is simple and consistent. I can do quick conversions between metric and imperial in my head, but especially when it comes to volumetric measures, I cannot be sure if British or US Customary units are…
ChP
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3
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1 answer

What does L mean in Uncertainty Measurement Result U(E)=0.08+1.2L ;k=2?

I'm calculating the combined measurement uncertainty u(c) of a measurement for a length displacement sensor. Amongst other factors, one individual uncertainty affecting the error of measurement is the uncertainty of the gage block I'm using. In the…
spe4ker
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3
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2 answers

What does 12 bit resolution mean?

I'm looking at this inclinometer and in the features it says "12 bit resolution." I'm looking for a resolution of up to a 1/10th of a degree but don't understand what the 12 bit resolution means.
Mohanachz
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3
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2 answers

What is the "tl" unit of weight measurement?

I recently purchased a digital scale from eBay. According to the listing it can weigh in the following units: Multiple Weighting Units: g, oz, tl, ct. Screenshot of that page: Now I know that "g" is grams, "oz" is ounces, and "ct" is carats (and…
Nick Gammon
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2
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0 answers

Why aren't there laser diode based monochromatic sources for optical flats?

So at work we have some bent things that we want to quantify for flatness. I went looking for optical flats and monochromatic sources. Even on my favorite source of good-but-cheap stuff (MSC Direct), all the sources appear to use helium emission. …
TimWescott
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2
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0 answers

Measuring an irregular cavity

A friend has a compartment in the center console of his car, he has asked me to help resize, reorder and add padding to the compartment. Basically the kind of things I'd need to know are the dimensions of the overall cavity to know what will fit,…
Johnson_Atoll
2
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2 answers

Why are 0-10V signals de-facto standard in HVAC applications, when 4-20mA is more common in other applications?

I've been involved in a few projects with HVAC systems, where sensors etc. generally used 0-10 V signals, and looking at catalogues of Buderus and other suppliers this still appears to be the standard. In other industrial applications, you typically…
mart
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2
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0 answers

How can I calculate the smallest voltage a given adc can read?

I have a project where I'd need to measure small voltage (0.05 mV) output of a wheatstone bridge with an arduino mini pro. Based on my previous question most probably it can't be done with its analogue input directly. what is the range of the…
Hegedus.Cs
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2
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4 answers

Sylvac UL 4 - USB - (Send data) reports 'no.data'?

Using the sylvac UL 4 Each time I invoke the (send data) function the sylvac LED panel reports 'no.data'. To mention the obvious but nothing is received at the connected USB device. My question is. . How do force the sylvac device to (have data)…
Joseph
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2
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3 answers

Cutting a larger circle on center of a smaller circle

At work, we cut a 6" hole in the wall for a duct. Later we decided we now want a 10 inch duct in the same place. what tricks are there to center the larger hole over the center of the smaller hole if it is already cut? I'm using a hand saw to cut…
Ryan
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