# LabVIEW

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## Problem using units in simple calculations (LabView 5.01)

I'm having trouble incorporating units, even for very simple calculations.
For example, suppose I create a numeric control with units "m" (meters). I
then take the square root of this number and direct the output to a numeric
indicator. Obviously, the units of the result must be m^0.5, but LabView
doesn't recognize this as a valid unit for the indicator; however, if I
specify the units for the output indicator to be "m", everything works, even
though this is clearly incorrect!

Jim Rathman
Message 1 of 4
(1,794 Views)

## Re: Problem using units in simple calculations (LabView 5.01)

Hi Jim and group:
I think the unit facilities are intended to be used over Engineering
prefixes like micro, nano, pico... in order to help you to don't confuse
magnitude orders.
I think is not very suitable for other cases. Is most a trouble than a help
because you have to define the unit in each constant and whatever...

--
Francisco Javier Fernandez Luna
Ingeniero Tec. Industrial en Electronica.
Tel: 619 81 98 31
franciscojavier.luna@uca.es
ó pacoluna@postmark.net
Si prefiere que conteste a sus preguntas en español, por favor, hagamelo
saber.

"Let's make things better" (PHILIPS)
James F. Rathman escribió en el mensaje de
noticias 7u5fu2\$i7f\$1@charm.magnus.acs.ohio-state.ed
u...
> I'm having trouble incorporating units, even for very simple calculations.
> For example, suppose I create a numeric control with units "m" (meters). I
> then take the square root of this number and direct the output to a
numeric
> indicator. Obviously, the units of the result must be m^0.5, but LabView
> doesn't recognize this as a valid unit for the indicator; however, if I
> specify the units for the output indicator to be "m", everything works,
even
> though this is clearly incorrect!
>
> Jim Rathman
>
>
Message 2 of 4
(1,794 Views)

## Re: Problem using units in simple calculations (LabView 5.01)

You have just shown yourself how units work (and don't work) within LabVIEW.
Unitless values or unary operations acting on values with units do not
modify the original value's units. Yes, it would be nice if units worked
better than they do; part of the limitation is likely imposed by LabVIEW's
set of known units, m^0.5 (and other fractional powers of units) not being
among them.

Code well, and prosper!
__________________________________________________________
Douglas A. Femec, Software Engineer, Viewpoint Software Solutions, Inc.
2320 Brighton-Henrietta Townline Road, Rochester, NY 14623
(716) 475-9559, ext. 18 (voice); (716) 475-9645 (fax)
Doug@ViewpointUSA.com; www.ViewpointUSA.com

James F. Rathman wrote in message
news:7u5fu2\$i7f
\$1@charm.magnus.acs.ohio-state.edu...
> I'm having trouble incorporating units, even for very simple calculations.
> For example, suppose I create a numeric control with units "m" (meters). I
> then take the square root of this number and direct the output to a
numeric
> indicator. Obviously, the units of the result must be m^0.5, but LabView
> doesn't recognize this as a valid unit for the indicator; however, if I
> specify the units for the output indicator to be "m", everything works,
even
> though this is clearly incorrect!
>
> Jim Rathman
>
>
Message 3 of 4
(1,794 Views)

## Re: Problem using units in simple calculations (LabView 5.01)

Thanks. This seems to me to be a big problem - it's bad enough that LabVIEW
can't handle units as simple and common as m^0.5, but the fact that it in
some cases doesn't even report an error despite botching the units is
obviously much worse. I guess the lesson is to avoid using units until
LabVIEW does a proper implementation of this feature.

Jim

Doug Femec wrote in message <7u7gr9\$290e\$1@news.inc.net>...
>You have just shown yourself how units work (and don't work) within
LabVIEW.
>Unitless values or unary operations acting on values with units do not
>modify the original value's units. Yes, it would be nice if units worked
>better than they do; part of the limitation is likely imposed by LabVIEW's
>set of known units, m^0.5 (and other fractional powe
rs of units) not being
>among them.
>
>Code well, and prosper!
>__________________________________________________________
>Douglas A. Femec, Software Engineer, Viewpoint Software Solutions, Inc.
>2320 Brighton-Henrietta Townline Road, Rochester, NY 14623
>(716) 475-9559, ext. 18 (voice); (716) 475-9645 (fax)
>Doug@ViewpointUSA.com; www.ViewpointUSA.com
>
>
>James F. Rathman wrote in message
>news:7u5fu2\$i7f\$1@charm.magnus.acs.ohio-state.edu...
>> I'm having trouble incorporating units, even for very simple
calculations.
>> For example, suppose I create a numeric control with units "m" (meters).
I
>> then take the square root of this number and direct the output to a
>numeric
>> indicator. Obviously, the units of the result must be m^0.5, but LabView
>> doesn't recognize this as a valid unit for the indicator; however, if I
>> specify the units for the output indicator to be "m", everything works,
>even
>> though this is clearly incorrect!
>>
>> Jim Ra
thman
>>
>>
>
>
Message 4 of 4
(1,794 Views)