Dashboard instrumentation system for vehicle, - uses standard 2-coil electric meter indicators and central current transducers with memorised correction table

摘要

The instrumentation system includes various types of sensors and transducers (11-14) connected to analogue switches (Sw1-Sw4) which are consecutively enabled and disabled by an impulse control unit (60). Only four switches are shown but if there are more, a decoder circuit (50) may be provided to identify each data source. In order to drive the two-coil indicators (15 to 44), a microprocessor controlled unit (70) is provided which receives the voltage magnitudes from the various transdcuers. The information is passed on to a table which has stored the digital equivalent of two outputs corresponding to the two coils of each instrument. The corresponding analogue outputs are then passed on along the two bus lines (71, 72) to all the Sample & Hold circuits (13, 22, 32, 42); however, only the selected one can actually recieve the sampled level. ADVANTAGE - Errors due to instrument characteristics can be compensated in memory table of distributor unit. This possibility provides more accurate status indicators on car's dashboard.