What is the scanning cycle of the Siemens CPU222?
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This post was last edited by zhaohh3211 on 2009-5-26 07:37. When using a PLC, one doesn’t pay attention to the scanning cycle; I’m wondering what the scanning cycle is for the 222CPU in Siemens’ 200 series Is it adjustable, or is it fixed?
The scanning cycle of Siemens Series 200 varies depending on the size of the program you write. You can monitor these variables: Last_Scan SMW22 – the time of the last scan; Minimum_Scan SMW24 – the shortest scanning time since the PLC started running; Maximum_Scan SMW26 – the longest scanning time since the PLC started running
It can only be determined through online monitoring; it’s impossible to tell when the program is not running~ ~ It can be said that this is the case with all PLCs as well~
It’s in the order of hundreds of milliseconds; generally, the size of a program does not exceed the scanning cycle, so a basic understanding is sufficient.
The information you mentioned can be viewed in MICRO/WIN’s menu “PLC---Information”.