Good day everyone! I have some question relate with above subject. While i try make protocol for the CJ2M PLC. i found out "Primary Expression (yN+x)" function but i cannt understand what`s this for. even i tried to find in the reference manual. i can not. you can find it "Message Editor" -> "Message Variable" -> "Variable" sorry i tried to upload picture many times but it kept showing failed to upload. hope so i could find the answer. thank you!