... on the transducer: DS2,SGND,DS------The semaphore shields(copper wire net)EXT_EXT+------------------excitation coilTR,TR ... down on the transducer:SIG2,SGND,SIG1-----------semaphore electrodeICCOM,ICOVT,INSW-----frontispiece and obverse 4~ ... and obversepulse frequency Sensor:SIG1,SIG2,SGND---------- semaphore electrode DS1,DS2-----------semaphore countercheck(brass wires net) EXT+,EXT- --------------- ...