西门子840D系统

NCK的清空:                                                                                                                      
1. 将S3开关由“0”拨至“1”                                                                                                  
2. 按NCU上的RESET键（数码管闪烁“5”“6”）                                                                
3. 当数码管显示的值变为“6”后，将S3开关由“1”拨回“0”                                                 
4. NCK被清空，标准的机床数据被装载到机床中。                                

PLC的清空：                                                                                                                           
1. S4开关从“0”拨到“2”（PR绿灯灭，PS红灯亮）                                                                   
2. S4开关从“2”拨到“3”（PS红灯先灭后亮，在PS灯重新亮起之后的3秒钟内完成下一步）     
3. S4开关从“3”到“2”到“3”到“2”，（PS红灯开始闪烁，证明PLC正在清空中）                     
4. 当PS红灯停止闪烁后，S4开关从“2”拨到“0”，（PR绿灯亮，PS红灯灭)PLC被清空。