Another approach, especially for NC control units, is the direct readout of data, e.g. the position or speed of the moving axes, from the human machine interface (HMI). A software tool was developed, which allows the direct read-out from the machine control without making any changes of the control units’ configuration. In this approach the dynamic data exchange (DDE) service was used, running on the windows based HMI of the NC control unit. This approach is described in [12].