Sigma EF-530 DG SUPER question

[kuul13]

Hi Guys

I have Sigma EF-530 DG SUPER, I am not able to figure out why it would not fire normal when I use it as slave flash. I use Nikon D80 and my inbuilt flash acts a master and Sigma a slave. As soon as my inbuilt flash fire, the Sigma should fire. It fires but not like normal flash of light. It fires for couple of seconds (continuous light). Not sure if it is something to do with batteries. I tried fully charged batteries too. It works just fine if I attach it to my camera.

Any ideas?? Any help would be appreciated.

My Sigma:
Sigma Imaging (UK) Ltd
http://www.sigma-imaging-uk.com/pdfs...Manual_NIK.pdf

Edit: Now I see that when I attach the flash to my camera and fire.. it works like a tubelight.. it blinks twice and then fire the flash. Did I mess up with some setting? I don't know if I did.