Hi

I want when one operator in one client open the faceplate the other clients can't open this faceplate As long as close faceplate

I use pcs7 v9 and APL library 

Dear,

Blocking of opening faceplates on another client is not standard functionality and also not sure how to esteblish this functionality with customization.

There is a standard solution if you want make sure one Client is in control: Multi Control Room Concept part of the Industry Library: 109976194

Please take a look at chapter Basic >> Multiple control room concept

Best regards,
Cedric