| 摘要 |
PURPOSE:To attain an analog output corresponding to a failure of a CPU, by detecting the absence of a clock signal at a detecting circuit, resetting a register for data signal and making all parts of a gate circuit for location selecting signal high in level. CONSTITUTION:In a detection circuit 8, each time a clock signal comes from a CPU1, a transistor (TR) turns on and charges charged in a capacitor C' are discharged. When a CPU1 is failed due to a failure, the clock signal is not given to the circuit 8, the charges in the capacitor C' are not discharged and when the potential exceeds a prescribed level, a register 21 is reset and a zero output is applied to a D-A converter 3. Outputs more than the level are applied to all OR circuits of a gate circuit 7 to bring the gates high in the level. All switches 41, 42 of a switching circuit 4 are turned on, the content of all sample hold circuits 51, 52 is made to zero to obtain zero output. |
