Dear Mr. Kumar,
There are a lot of judgments on this issue that a cheque given as a security, does not attract penal consequences of section 138 of NI Act. Because the cheque is not given against the legally enforceable liability. This is matter of face and disputed one, therfore wot u r required to do, u first need to prove that the cheque was given as a security, that can be proved under trial. Only making some averment taht the cheque was given as a security wud not suffice your casue. If u hav any corspondence, whereby u can prove that the said cheqe was security cheque, it wud help you out. Otherwise you need to prove it during trial and in the cross examination of the Authorised Representative of the Bank.
Let the complainant evidence be closed den the judgment can help u out, not before that stage is over.