I checked about the stalling of the PR2 SF stepper motor.

Unfortunately, when I opened the chamber lid, the stall condition was released.
I checked K1:VIS-PR2_SF_LVDTINF_GAS_INMON.
The LVDT was no longer sticking at the timing when I opened the lid, probably just before running the motor.

Therefore, I let the motor drive the entire range and measured the drive range of the stepper.
The drivable range of the stepper motor is currently at -50000 with a drive range of 0 to -175000.
The current position was set to (-14120), which is close to the position of the LVDT (-15035) at the initial start.

Other things I noticed.
The polarity of the motors was reversed.
The one where KeyStone is up is the negative direction of the motor (upward movement of the stepper).