A meter is a device capable of providing telemetry readings, and is functionally the same as your electrical meter. However, in process control they serve a different purpose such as monitoring the energy going through each substation, or water purified per day to measure business enfficency. Some meters are process critical, in that they monitor the levels of a chemical into a water supply, or amount of water into a reactor cooling tower. Others are much smaller and cheaper, and only serve to show the electricity you consume in a home. [Devices]