PlotArc has error when Sweep angle <5?

[KhanhJST]

I used LabWindows/CVI for plotting ARC. I can't plot arc when Sweep angle is less than five.

could you help me solve that problem?

PlotArc(panel,PANEL_GRAPH1,0, 40, 40, 0, 8, 4, VAL_WHITE, VAL_TRANSPARENT);

my email: phan_khanh13@yahoo.com

Best regards!

Thanks

[Snowman 6008]

By specifiying PlotArc(panel,PANEL_GRAPH1,0, 40, 40, 0, 8, 4, VAL_WHITE, VAL_TRANSPARENT); you are settingsweep angle in tenths of degrees, so you are writing 4 tenths of a degree ( http://zone.ni.com/reference/en-XX/help/370051P-01/cvi/uiref/cviplotarc/ ) . If you modify the x1, and y2 you can see this however small when i plotted using your example and this line,i got the following graph

PlotArc(panel,PANEL_GRAPH1,38, 40, 40, 38, 8, 4, VAL_WHITE, VAL_TRANSPARENT);    

Again it is very difficult to see, but if you loook at x = 40, and y = 39, you can see 4tenths of a degree plotted. It looks like a single white dot.

Message Edited by Snowman 6008 on 01-14-2010 10:32 AM

[KhanhJST]

Thank Snowman 6008 for your answer.

I knew i was setting sweep angle 4 tenths of a degree.

When i set it 5 tenths of a degree and i zoomed in, i saw a line. But when i set it -0.5<sweep angle<0.5(-5<arcAngle<5) and zoomed in, i could't see a line. it is only small dot.

when x1, y1 and x2, y2 are of small value, the length of line is short(Line = radius*sweep angle), but when they are of big value, the length of line will be long and affect the graph.

I gave you two pics with 4 tenths of a degree and 5 tenths of a degree.

Can you try two this way?

Thank you again.

[Snowman 6008]

What exactly are you trying to accomplish? Would it be feasable to scale up the grah and angle to reproduce the desired arc you are looking for? It looks like we are running into a limitation of the graphing units. You'll notice that the graph scale in your picture never shows more than three digits after the decimal.

[Snowman 6008]

After further investigation, this appears to be a known issue. The reference number for this issue is 126708. You can check the release notes of CVI for issue numbers that are fixed for that given release.

[PQH]

Hi Snowman,

I am using LabWindows/CVI 2009 and the issue still persits. 

I did a check on the list of  bug fixes over different releases of LabWindows/CVI, I could not find the ID you mentioned (126708) in the bug fix list.

http://zone.ni.com/devzone/cda/tut/p/id/6609

So I assumed the bug is still there. Please correct me if I am wrong.

By the way, is there any work-around for this bug? Is NI R&D planning to fix this bug any time in the near future?

Thanks.

PQH

[KhanhJST]

Hi Snowman and PQH,

  I still couldn't find the ID of issue.

Snowman, can you give me the link of that website?

Thank you!

Khanh

[Snowman 6008]

We have not released a version that specifically addresses the issue, so you will not find that ID listed on any of the release notes as of January 26, 2009. As for a work around, I suggest not using the zoom and scaling your angle along with your axes.