Extending or changing systems that are in operation 24fl should disturb the operation as little as possible. Therefore, the extensions or changes should have been thoroughly tested in advance under conditions comparable to operational conditions. Baggage handling systems is typically an area to which these requirements apply. Control software is one of the main components for baggage handling systems, at high and low level. Software is often the reason for system failure. Therefore, a need exists for tools that support testing without involving the real equipment on site. By using a simulation environment for emulating baggage handling equipment it was possible to test the low level control software without involving any real baggage handling equipment. The simulation environment enabled detailed tests and provided insight into the behaviour of the PLC for our client. This approach saved significant lead time in the project and reduced the required time for testing on-site.