Try to do this, Mehmet.
ipmitool -I lanplus -U USERID -P PASSW0RD -H xxx.xxx.xxx.xxx power on/off/reset
ipmitool -I lanplus -U USERID -P PASSW0RD -H xxx.xxx.xxx.xxx sol activate/deactivate
The "USERID" and "PASSW0RD" are the actual credential that I found on a manual for their other system. 0 = number zero
In the system's BIOS, go to SuperIO, and change the baud rate to 115200, UTF-8, that will give you a better output. Don't use the ipmitool on the Mac, it doesn't have lanplus option and will give you a lot of strange issues.
How's your CentOS 7, will you be able to halt/reboot it? I have 8 of them connected to ACUPWR 1500w, all of them cannot reboot/halt correctly, I have to reset/power off them manually.