Using of degrees in Tangent vi

[NormanSim]

Hi, Good day! May I know how I can calculate base on degrees by using Tangent vi in LabVIEW 7.1? The tangent vi default input is in radians. For example: (tan -0.0680 * 27000 + (-36.6))= -68.644 when using degrees to calculate. How I can use the vi provided in LabVIEW 7.1 to achieve same result? Thank you in advance for the advice! Best Regards, Norman

[altenbach]

Just convert your input ro radians before using the tangent function.

(you could even wrap the conversion and function in a new subVI that does what you want).

[parthabe]

If I m right, you ve do a pi/180 to convert deg to rad.

Feed this value to the Tangent.vi, thats it.

[altenbach]

(top of image) Easies to convert would be a compound node.

(bottom image) If the angle comes from a FP control, you can set the units of the control to "deg" and the wire will be automatically be in radians! 🙂

If you set the units right in the bottom case, both will give the same result.

Message Edited by altenbach on 09-04-2007 01:00 AM

[parthabe]

One more option without using the Unit label.

Use Convert Unit instead.

[altenbach]

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@parthabe wrote:

One more option without using the Unit label.

Use Convert Unit instead.

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Actually, all you need is the "deg" node to tell it's an angle. Internally, it will be in radians. Try it! 😄

Message Edited by altenbach on 09-04-2007 08:14 AM

[parthabe]

You re right, Sir, as usual as always !

But, please explain me that internal behaviour of the wire value in radians...

[altenbach]

In this case, the third paragraph if the section "Convert Unit Details" applies:

http://zone.ni.com/reference/en-XX/help/371361D-01/glang/convert_unit/

Quote: "If the input is a pure number, LabVIEW assigns the unit you specify in the Convert Unit function to the number and returns that physical number in the base unit (or a combination of base units) for that class of measurement, as indicated in the following table."

The "base unit" of an angle is rad. Yes, it's a bit confusing but at least documented. 😄

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For some fun, look at the attached VI diagram and front panel. Don't run it yet!!!!

Can you tell what all the indicators will show without running it?

Now run it! Were you right? 😄

Message Edited by altenbach on 09-04-2007 10:47 PM

[parthabe]

Thank you, Sir !

[parthabe]

A related discussion...

http://forums.ni.com/ni/board/message?board.id=170&message.id=272020