ASISetStartPos call has no effect

santonov

Hi there,

I am using ZWO ASI183MM camera with SDK v.1.13.0523 under Windows 10. I built demo program supplied with SDK. When I try to change start position of frame, it always reset to zero. In debugger I see that when I pass some values into ASISetStartPos then read it, it always returns zeros:

This is code from your demo program (demoDlg.cpp .846)

ASISetStartPos(iSelectedID, m_iStartX, m_iStartY);

ASIGetStartPos(iSelectedID, &m_iStartX, &m_iStartY);

Second call returns 0,0. How it supposed to work? When I load image after start position set I don't see any effect.

I also see that setting ROI behaves the same way -- it always return default ROI.

Thanks,

Sergei

chad

Hi Sergei,

I tested the demo, it works fine.

When you set the start position, we will do 2 checks:

1st:

This position coordinate should satisfy the internal setting rules of sensor. Most of the time, they have to satisfy that the start position of width is a multiple of 2, and the start position of height is a multiple of 4.

You can set any value and it will be automatically corrected in our SDK. So after you set it successfully, please use ASIGetStartPos to get the real value to synchronize with your interface.

2nd:

ROI should not exceed the maximum scope of the image。

For example: 183's max size is 5496*3672, then you want an ROI size: 2000*1000. Then the start position of width should not exceed 3496 (=5496-2000), and the start position of height should not exceed 2672(=3672-1000). If you exceed them, they will be automatically corrected to 0. Beside, you also need to think about the binning mode here.

Thanks

Chad