Lingua francas have developed around the world throughout human history, sometimes for commercial reasons but also for religious, diplomatic and administrative convenience, and as a means of exchanging information between scientists and other scholars of different nationalities.
A vernacular language is used as a native language in a community but, a lingua franca is used beyond the boundaries of its original community and is used as a second language for communication between groups. For example, English is a vernacular in the United Kingdom but is used as a lingua franca in Russian and French serve a similar purpose as industrial/educational lingua francas in many areas.
International auxiliary languages such as Esperanto have not had a great degree of adoption globally so they cannot be described as global lingua francas.
During the era of Sikh Empire of Punjab, the Punjabi had not a great degree of adoption out of Punjab, therefore, the native language Punjabi was the vernacular language and regional lingua franca Persian was the official language of Sikh Empire of Punjab.