| 摘要 |
<p>PURPOSE:To measure the number of vehicles accurately, by a method wherein vehicles leaving and arriving in two different directions are detected individually with two sensors and then, the number of vehicles is counted after a fixed time passes from the rising of an output waveform of the one sensor while the output of the other sensor is off. CONSTITUTION:Concrete mixer trucks 1 leave and arrive alternately in form two different directions at a loading position for pouring ready-mixed concrete from an injection pipe 2. To detect the presence of a vehicle, first and second sensors 4a and 4b are set at two points so as to allow the checking of vehicles in two directions. If a specified time passes after the sensor 4a is turned ON while the sensor 4b is OFF, one vehicle is counted by outputting one timing pulse with the passage of the specified time. If the sensor 4b is not turned OFF when a specified time passes after the sensor 4a is turned ON, one vehicle is counted with the passage of additional fixed time after the sensor 4b is turned OFF. Thus, the number of vehicles can be counted accurately regardless of partial duplication of outputs from the two sensors 4a and 4b.</p> |
