Is there any formula for drawing a circle through co-ordinates

[Giridhar_Rajan]

Hi,

I'm using the draw a circular arc with the help of two motors, using the motion VIs in LabVIEW. The circular arc VI in LabVIEW 7.1 asks for the following inputs,

1.) Start angle

2.) Travel angle

3.) Radius

But I do not have any info abt. angles. What I know is

1.) Start position of X & Y.

2.) End position of X & Y.

3.) Radius

I'm looking for a formula which converts the start pos, end pos and radius parameters to start angle, travel engle and radius, as required by our LabVIEW draw arc motion VI. Somebody please provide a formula or a VI that does the job.

Regards,

Giridhar Rajan

Automation Engineer

Cruiser Controls

Mumbai, India 

[JesseD]

Hello Giridhar,

Here's an external link to a website that describes how to calculate angles within a right triangle.  This will help you to calculate the start angle.  For this, the hypotenuse would be your radius between the center of the circle and the starting point.

Here's a link that describes how to calculate angles of arcs based on radius and chord length.  The length of the chord is the distance between the two end points.

These are just the first two external sites that I found when searching the internet.  There are probably other similar sites that may also help you out.

Best Regards,

Jesse D.
Applications Engineering
National Instruments

[Giridhar_Rajan]

Hi Jesse,

I went through the links that u sent. They were very useful. Thanks

Regards,

Giridhar Rajan

Automation Engineer

Cruiser Controls

Mumbai, India