The PM system provides the following meter reading types:
- Accumulated Value: Accumulated value readings document life-to-date values where there is not a device tracking a running total. For example, a life-to-date value is documented for the total fuel used by a vehicle, although the fuel gauge displays only an analog indication of the current tank level.
- Increasing Value: Constantly increasing life-to-date total value as indicated by a monitoring device. For example, an odometer displays the total miles driven for a vehicle.
- Pre-defined Value: Possible meter readings are limited to pre-defined values such as OFF or ON, HOT or COLD, etc.
- Variable Value: A monitoring device indicates a randomly changing value rather than tracking a running total. For example, a thermometer, a voltmeter, a pressure gauge, etc.