| 摘要 |
A speedometer system for automatically calibrating a speedometer by adjusting the speedometer drive to take into account the varying wheel sizes of a locomotive which comprises: at least one speed probe; a speedometer drive; a speedometer; a gate for enabling and disabling the normal speed signal from the speed probe; a programmable counter for transmitting a test speed signal to the speedometer drive to produce a test speed current; a gate for enabling and disabling the transmission of the test speed signal to the speedometer drive; and a microprocessor which is capable of processing a signal representative of wheel size, calculating a test signal frequency, causing the counter to create and transmit the test signal, measuring the speedometer current, and signaling a digital potentiometer to increase or decrease the resistance on the speedometer drive until a full scale current value is measured.
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