When the PLC is not networked to other controllers or devices, what is the primary use of a USB connection?

Using a USB connection when the PLC is not networked primarily facilitates the uploading and downloading of PLC programs. This capability allows programmers and technicians to interface directly with the PLC, making it easier to transfer updated program files or retrieve the existing program for review or modification. The USB connection provides a convenient and direct link for data transfer, which is especially useful during programming, troubleshooting, or maintenance tasks, where direct access to the PLC's internal software is required.

In scenarios where the PLC is not connected to a broader network, the USB serves as one of the most reliable methods to efficiently manage software changes without the need for additional networking hardware or configurations, ensuring that the programming process remains straightforward and accessible. This direct interaction with the PLC helps maintain the integrity and functionality of the controller's programs, which is essential for proper operations.