[Cause]
The node with the node number displayed in the FL-net message left the network.
[Countermeasure]
For the node that left the network, check the device settings and cable connections for abnormalities. Check whether error messages were issued at the same time. If an error occurred, eliminate its cause first. Set the severity of this error to WARN or STOP for each node using the Error Severity item on the participating node detailed setup screen.