Tamil nadu VAT

As regards tamlinadu vat act the regn is to be taken when the turnover is not less than Rs 10 laks per year for dealers purchasing and selling in side the state.

In this regard i would like to know whether the limit of exemption up to 10 laks is available  each year.?

If so what to do regarding the input tax paid on purchases?can it  be set off against the vat collected later?