21F7		4

	Cannot take arm semaphore
	1. A task having no arm semaphore tried to execute robot motion-related commands. 2. Attempt was made to take arm semaphore but another task already had the arm semaphore.
	1. Take the arm semaphore with the TAKEARM statement, and execute the robot motion related commands. 2. Change the programs so that multiple programs do not attempt to take the arm semaphore at the same time.