When adding a device to a Logix500 controller, which statement is true?

The statement that is correct in the context of adding a device to a Logix500 controller is that modules can indeed be added online or offline. This ability allows users to configure and implement changes without interrupting the operation of the controller, making maintenance and upgrades more efficient. Module Discovery is a feature that helps identify connected devices while the system is online, allowing users to integrate new devices into the existing configuration seamlessly.

While option B suggests that Module Discovery cannot be used when online, this is misleading because this feature is designed precisely for use when the system is online, enabling the identification of new or existing devices in real time.

It is also true that while some operations like adding or deleting modules can be constrained based on the I/O points and the operational states of those points, the flexibility to manage modules online typically permits changes that do not disrupt ongoing processes, provided proper procedural steps are followed.

The ability to change the communications format parameter online is generally limited, as these adjustments often require a configuration restart for certain devices to recognize the modifications. Thus, understanding the operational capacities of Logix500 controllers enhances effective system management.