发布于 2006-12-15 15:33:37
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昨天在STEP7帮助文档中发现如下语句:
Compared with direct access to the input/output modules, the main advantage of accessing the process image is that the CPU has a consistent image of the process signals for the duration of one program cycle.
感觉映像区最大的作还是保证数据的一致性