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Method of testing control devices

  • US 4,703,258 A
  • Filed: 02/21/1986
  • Issued: 10/27/1987
  • Est. Priority Date: 09/04/1984
  • Status: Expired due to Fees
First Claim
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1. Method of testing via a single test line a plurality of controller devices in a motor vehicle, which perform functions in dependency on sensor signals and, in the event of a function error, store an error data word and upon interrogation convert the stored data word into an error signal or a sequence of signals, comprising the steps of:

  • assigning to each controller device a different priority corresponding to a length of a priority pulse generated by the controller device;

    applying to the test line an excitation signal which sets the test line to a logic level corresponding to the priority pulses;

    simultaneously applying the priority pulses of all controller devices to the test line and, at a time point of expiration of the longest priority pulse, interrogating for a predetermined time interval the stored error data word in the corresponding controller device and transmitting the error signal to an indicator, then applying the priority pulses of the remaining controller devices to the test line and at a time point of expiration of the next longest priority pulse, repeating the application and interrogation steps for the remaining controller devices until error signals from all controller devices are transmitted to the indicator.

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