Hi @phunggiathanh
you may look for the library CXA_ModbusRTU in the folder you can see in my screenshot. It is automatically in from version 1.12 on. If you cannot find it, maybe something went wrong with your installation of ctrlX PLC Engineering, try to reinstall it. I recommend to change to the latest LTS Release of your ctrlX Platform, 1.20.x or 2.6.x , depending which license you have. ctrlX WORKS (boschrexroth.com)
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