This model replaced the 9990 that was manufactured until 2005, the B16 has no outburst with compressed air.
Early models have a 240VAC fan with damper (item no. 612), together with circuit board ver. 2.0.
The circuit board is characterized by its rectangular transformer.
Later models were equipped with a 24VDC fan (art. 1614) which is speed controlled from the menus in the PLC, this together with circuit board ver. 3.0
or ver. 3.1 which was in B16 also, circuit boards 3.0 and 3.1 are characterized by their round transformer.