is it possible to get current time from myRIO RT side?
I have studied Get Timestamp vi but I think that I can't get there current time.
If I recall correctly, you can read the time on the RT target of the myRIO just fine. The problem is that there is no backup battery, so every time myRIO reboots, the time resets. One option is to have a time-sync mechanism in your program that sets the time every time your program starts up (assuming that it is connected to a PC when it starts). After that, you can get the time from the RT.
You can use a battery powered real time clock (e.g. RTC DS1307) to update the myRIO system time after reboot.
This and some more options you can find on community: How do I change time on myRIO?