| 摘要 |
PURPOSE:To detect a fault of a speed sensor effectively and easily, by comparing the lower limit and upper limit set values of a car speed, etc. in each speed change stage of an automatic speed change gear, with a speed signal from the speed sensor. CONSTITUTION:For instance, it is supposed that a dump truck is running by a speed change stage F1. In case of this speed change stage F1, only a switch SW2 is on, the lower limit set value S1 and the upper limit set value S5 of a memory MOR2 are provided to a comparator COMP through the switch SW2, respectively. The COMP compares these set values S1, S5 with a speed signal V from a speed sensor 1, and outputs a signal of H level in case of S1<V<S5 and a signal of L level in case of S1>V or V>S5, respectively. This output signal is applied to an alarm device 4. The alarm device 4 lights an alarm lamp which is not shown in the figure, when an input signal is in an L level, and a warning about a fault of the speed sensor 1 is given. In this way, a fault of the speed sensor is detected. |
