The WatchMate 850, WatchMate Vision, XB-6000 and XB-8000 are Class B devices so it will send position reports every 30 seconds when you are moving faster than 2 knots, otherwise it drops back to every 3 minutes. Other information such as your vessel's name, size and type, is sent every 6 minutes.
The WatchMate will display a warning symbol if your transmissions are not being sent for any reason. The XB Transponders status LED will change color to orange. You can also query the reason for the status change using the vmAIS Configuration and Status Utility or WatchMate App over USB or WiFi.