Visual indicators should be clear for ease of reading and the scale well defined.
Rotameters need to be selected for flow rates, fluid density, and their output
value should be corrected for temperature variations from look-up tables. Care
needs to be taken to ensure that the thermometer bulbs are correctly placed in
the fluid for temperature measurement and do not touch the container walls,
as this can affect the temperature reading. When measuring liquid levels and
liquid and gas pressures, the instrument should have conditioning baffles to minimize
pressure and level fluctuations which can introduce uncertainties into the
readings.