| 摘要 |
<p>PURPOSE:To decrease the malfunction of an arithmetic memory due to noise by providing printed circuit boards where each electric power supply circuit and input/output section is arranged so as to approach each ground plane of a controller and an extended input/output unit. CONSTITUTION:The input/output section, an interface section and the power supply section of the controller are connected on a printed board 22 and arranged to approach a ground 24a comprised of a metallic case and an earthing face 21, and a printed board 25 on which the operating memory device is connected is arranged at the upper part. On the other hand, in the extended input/ output unit, a printed board 23 on which the power supply section, input/output section and interface section are connected is arranged so as to approach a ground plane 24b. Thus, a noise going to invade from the input/output section and the power supply section is apt to be absorbed easily by the ground planes 24a, 24b so as to reduce the noise.</p> |
