Analyzing and maintaining the quality of control software is pivotal in the plant manufacturing industry. During software development, certain negative patterns frequently occur. These negative patterns are called code smells and are characterized by code that is hard to understand, maintain or expand. One such smell is duplicated code, also known as clones. Clones often result from clone-and-own reuse, which is common in practice. Detecting clones is crucial to avoid bug propagation and keep maintenance efforts low. This work deals with detecting clones in control software written in the domain-specific modeling language IEC 61499.