The communication format of the programmable logic controller DVP series can be changed through a special register. Under certain user applications, a user might forget the changed communication format after the change occurs, resulting in disconnection between a computer and the DVP series. When this happens, the user can restore the connection by taking the following steps. 1. Cut off the power of the programmable logic controller DVP series Turn the RUN/STOP switch to STOP as shown in the picture below. 2. Restart the programmable logic controller DVP series 3. At this time, the communication format of the DVP series will switch to the preset value: 9600, 7, Even, Stop bit = 1, station number = 1. The user can then modify the communication format through the WPLSoft software.