Monitoring magnetic valve circuit drift, e.g. for vehicle ABS, involves applying PWM input pulse sequence to switch elements to initiate difference measurement at subtraction stage by pulse counting

摘要

The method involves monitoring a multi-channel magnetic valve load with switching elements (8,15) and current regulators (6,13) associated with each channel. The duty cycle and/or a derived parameter is monitored and compared with a threshold value to detect errors. A PWM input pulse sequence (3,4) is applied to the switch elements to initiate a difference measurement at a subtraction stage determined from pulse counting in each channel.