| 摘要 |
PURPOSE: To check an intelligent output stage having electric loading at a downstream side, by adding trigger voltage for short time, to the intelligent output stage, and checking whether a high or low signal is existed in a monitor line, or not within two time phases after the trigger. CONSTITUTION: The wheel speed signals of the wheel speed sensors 1-4 of ABS device, are supplied to an evaluation circuit 5 includingμCPU 5a, to generate a trigger signal for the brake pressure controlling valves 6-9 through the circuit breakers 5b-5e to trigger the controlling valve 6-9. TheμCPU 5a intermittently supplies a short pulse to the breakers 5b-5e, and the corresponding pulse is generated on a monitor line 5f, when the error is not existed at the end of the pulse. TheμCPU 5a detects the high signal by sampling the monitor line 5f in the first time phase after a predetermined time, and further detects the low signal in the second time phase. The breakage, the earthing short and the short to the battery, can be detected from the pulse train.
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