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Why kgf measurement unit isn't available?

Why kgf measurement unit isn't available?

I'm building a data acquisition software, and the unit of the output must be kgf (kilogram-force).

But cannot find this unit on LabVIEW.

According to this page (http://zone.ni.com/reference/en-XX/help/371361F-01/lvhowto/available_units_in_labview/) LabVIEW doesn't have a kgf unit.

 

Can someone explain why we don't have a widely used unit available?

 

Thanks for the help.

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Message 1 of 7
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Re: Why kgf measurement unit isn't available?


@mthheitor wrote:

I'm building a data acquisition software, and the unit of the output must be kgf (kilogram-force).

But cannot find this unit on LabVIEW.

According to this page (http://zone.ni.com/reference/en-XX/help/371361F-01/lvhowto/available_units_in_labview/) LabVIEW doesn't have a kgf unit.

 

Can someone explain why we don't have a widely used unit available?

 

Thanks for the help.


Use Newtons multiplied by 9.80665

Message 2 of 7
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Re: Why kgf measurement unit isn't available?

Yeah, this is a workaround.

But it's annoying, because the rest of my numeric indicators will have a unit and two controllers will not have a associate unit.

Additionally this workaround ruins my plan to programmatically change the font color of my indicators.

The same problem occurs with revolutions per minute (RPM)

 

I accept your suggestion, but if NI add these units or let the users add units LabVIEW will improve, for sure.

 

Thanks for the help.

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Message 3 of 7
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Re: Why kgf measurement unit isn't available?


@mthheitor wrote:

Yeah, this is a workaround.

But it's annoying, because the rest of my numeric indicators will have a unit and two controllers will not have a associate unit.

Additionally this workaround ruins my plan to programmatically change the font color of my indicators.

The same problem occurs with revolutions per minute (RPM)

 

I accept your suggestion, but if NI add these units or let the users add units LabVIEW will improve, for sure.

 

Thanks for the help.


That's going to be a hard sell because NI recommends avoiding the use of units.  I can't seem to reference that at the moment, but I know I saw that somewhere.

 

Also, see this topic for some caveats on using them, and why most LabVIEW programmers shy away from using them.  It's a pretty old topic, but I'm sure that it's still relevant.

Bill
CLD
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.
Humble author of the CLAD Nugget.
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Message 4 of 7
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Re: Why kgf measurement unit isn't available?

Honestly,

I have very limited use for LabVIEW Units I just mess with the numeric format string and leave the numeric dimensionless

Capture.PNG

I believe Bilko is referring to this caveat:

Associating Units with a Numeric Control or Indicator

Note  National Instruments recommends you do not use units with a numeric object formatted for absolute time.
Message 5 of 7
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Re: Why kgf measurement unit isn't available?

Hi mth,

 

why we don't have a widely used unit available?

Why do you think "kgf" is widely used?

If you you would ask for a SI unit - but kgf is not SI-conform. (1N×1g is.)

 

Best regards,
GerdW
CLAD expired, using 2009SP1 + LV2011SP1 + LV2017 (+LV2018 sometimes) on Win7+cRIO
Kudos are welcome Smiley Wink

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Re: Why kgf measurement unit isn't available?

Use of units was a nice idea and when it was introduced back in LabVIEW 3 or 4 I thought it was a great feature. But in reality it never really made its promisses true, and while some of it is because of limitations in what LabVIEW supports, some of it goes much further with the fundamental meaning of units that is unfortunately not very coherent between different areas. While the physics world has mostly standardized on the so called SI units which form a fairly cohorent unit system, this can't be said at all about many real world units. Honestly I didn't even know there existed something like kgf and it seems the real SI unit for that is actually Newton.

 

From the Wikipedia:

 

Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI

 

and:

 

The gram-force and kilogram-force were never well-defined units until the CGPM adopted a standard acceleration of gravity of 980.665 cm/s2for this purpose in 1901,[5] though they had been used in low-precision measurements of force before that time. The kilogram-force has never been a part of the International System of Units (SI), which was introduced in 1960. The SI unit of force is the newton.

 

NI made an attempt to implement the SI units when implementing the unit system in LabVIEW and added some common non SI units mostly coming from the imperial measurement units. Implementing all possible units would be not only an immense but in reality even impossible task as there would be actually naming clashes between different such units. They had to draw the line somewhere and units has been an area in LabVIEW where little attention has been given to after the initial release, including known bugs in mathematical operators that have never been solved.

 

Part of the LabVIEW shortcomings are in the fact that there are actually bugs in the threatement of units in some mathematical operators, and another thing I frequently run into whenever I tried to use units was the fact that I had to constantly adding "to unit" and "from unit" conversion nodes all over the place because some functions do not support proper unit handling and simply assume the basic unit without an easy way to specify a different unit or it simply was not convinient at that place, or the customer wanted to use some non-standard unit anyways. In general my conclusion has been that use of units in LabVIEW are causing more trouble then they solve, and that is only partly caused by LabVIEW itself.

Rolf Kalbermatter
Averna BV
LabVIEW ArchitectLabVIEW ChampionLabVIEW Instructor
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