Please refer to the following steps: 1.Set the rotation speed S to 0 and measure if the voltage is 0V or not. If not, please check the settings of parameter code 37 and adjust level 0. 2.Set the rotation speed S to 8000 corresponding to parameter code 409 (Max. rotation speed of master axis) and measure if the voltage is 10V or not. If not, please check the settings of parameter code 39 and adjust the slope rate. 3.Test if the setting values of S0 ~ S8000 corresponds to the voltage of 0V ~ 10V.