| 摘要 |
PURPOSE:To prevent step-out of a step motor by changing speed level of the step motor according to the relation between battery voltage and speed level in case a starter signal is off. CONSTITUTION:At the step 102, a position of the target step of a step motor is calculated, and is value is loaded in RAM. When a starter switch is on, the maximum speed level is set at 0 (Step 106). When the starter switch is off, the maximum speed level is acquired from the A/D conversion value of battery voltage and loaded in RAM (Step 105). When the starter switch is of, the operation speed of a throttle valve slows down as the battery voltage decreases. Thus, step-out of the step motor can be avoided by quickly recognizing battery voltage. drop.
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