Loadable C Functions as Released Library

In order to release safety-related C function block POUs with loadable C function code in a library, a code signing certificate with a private key is required.

The code signing certificate issued by a Certificate Authority ensures that the released library is trustworthy and has not been modified since it was last built and signed.
The private key associated with the signing certificate is used for the verification of the released safety-related library. Based on the private key, a signature is calculated and written to the safety inventory when releasing the library.

When referencing the released library in another project, PLCnext Engineer verifies the validity of the certificate. If the certificate is invalid, the library cannot be referenced and is rejected.

If a code signing certificate is necessary, you have to select the related private key file before releasing the library. You have obtained this key file (*.pfx) from the Certificate Authority. The private key file is a password-protected PKCS#12 file which contains the complete certification path. The certification path includes the signing certificate itself as well as its private key. The private key file is required to create the library.

The signing certificate you use for creating the library is derived from a root certificate or issuer certificates (in case of a certification hierarchy). The root certificate and the issuer certificates must be present in the Code Signing Trust Store of PLCnext Engineer.

Proceed as follows to add code signing certificates:

Start PLCnext Engineer as Windows administrator.
Open the 'Options' dialog.
In the 'Administration | Trust Stores' category, add the code signing certificates.

If the corresponding certificates are not available in the PLCnext Engineer Trust Store, the library cannot be released.

Note
Due to the particular requirements which apply to such a library and the contained C functions, the library creation is restricted to customers who purchased a special license.