Unlike other PLCs, the user program in the ZX20 controller series from Hermann Zander is 'burned' into an FPGA (Field Programmable Gate Array). This means that the program no longer runs, but is instead processed completely in parallel; the entire user program is 'converted into hardware', so to speak. The programmer is unaware of this: he creates his program in the familiar PLC language ST (Structured Text) and loads it into the controller as with a conventional PLC. This means that the cycle time of the controller is always constant at 0. The FPGA can be rewritten just as often as conventional microcontrollers. Mathematical operations such as addition, subtraction or multiplication through to the use of entire functions can be implemented via the programming interface and can then be played directly on the high-speed FPGA. Bus variants include an integrated Profinet IO device (ZX20TP) or an Ethercat slave card (ZX20TC), which can be used to integrate the individual controllers into the higher-level system.