Thank you for your advice @Veganic
But in that case, i think i gonna need double enet module, right?. One for plc to hmi and one for plc to robot.
In case which i want to do, dont need any enet module on plc, and it means less crowded electrical panel, and get more simplicity.
I tried something else, like below and it actually passed the test. But in that case still need a enet module on plc.
[ROBOT]--------Ethernet--------[PLC]--------RS422--------[HMI]
So it solves a little bit my situation but I still need to learn something about my main subject.