# Message Notification connection

Assign a tag to this connection. If this connection is not assigned, message handshaking cannot occur.

When the application is initially run, this connection is set to 0. When a message is written to the Message connection, the Message Notification is set to 1.

If the Message Handshake connection is not assigned, the Hold Time starts timing. When the Hold Time finishes timing, the Message Notification connection is reset to 0.

If the Message Handshake connection is assigned, the Message Notification connection is reset to 0 when the Message Handshake connection changes to a new non-zero value.

If an alarm with a Message flag is triggered while the Message Notification connection is set to 1, the alarm message will be queued until the Message Notification connection is reset. A maximum of 128 messages can be queued. (Messages are queued on a per-trigger basis. Messages from the same trigger will be queued on a first in-first out (FIFO) basis.)

If the message queue is full, the application logs a diagnostic error.

## See also

Message connection

Message Handshake connection