Morningstar TriStar Digital Meter (for TS-MPPT) TS-M-2. The meter will display a great deal of information about the TriStar controller and the operation of your system. In addition, the meter enables manual functions and controller diagnostics. These capabilities will increase your confidence that the system is working properly and will help you to improve system reliability, battery life, and system performance. It is worth the time getting to know your meter!