Method for determining the water quantity in the washing container of a washing machine

摘要

The economical electronic analog pressure measuring devices used for determining water levels generate output signals subject to tolerances, which must first be corrected for the precise driving of the inlet magnetic valve. Likewise, the actual deviations of the magnetic valve must be corrected with reference to flow velocities. A known device does not take this into account, that is to say expensive precision sensors and magnetic valves are necessary. In the method according to the invention, cheap analog pressure measuring devices, which are corrected, are used. In the method according to the invention, the output signals (Ua) generated by increasing pressure between two washing machine levels are measured, recorded and stored at exact time intervals. On the basis of a desired curve, which corresponds to an ideal analog pressure measuring device and the known appliance geometry, the output signals (Uaact) are matched to adequate output signals (Uades). By means of the accurate recording with time of the levels and of the water contents known herefrom, the influence quantities of the magnetic valve are also eliminated. The method according to the invention is suitable for application in programme-controlled washing machines and dishwashers. <IMAGE>