I had a problem with the digital output module 6ES7 422-1BL00-0AA0,
 used on a S7 / 400 CPU in a cold rolling process. One of the exits
 froze the signal in 1 direct and I needed to change the card. Has 
 anyone here experienced this problem? I need help to know how to 
 identify the defect in this output.

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Split from Help me with SM 442 problem.

Hello dear friend

Follow below link. it may help you 

https://support.industry.siemens.com/tf/WW/en/posts/help-me-with-sm-442-problem/62206?page=0&pageSize=10