Explain the direct and indirect level measurement
Direct means there’s direct contact with the fluid level being measured e.g. a float. Indirect means there’s no contact with the fluid e.g. ultrasonic level measurement. Direct measurement is performed by using the scale of the measuring instrument while in indirect measurements, the dimensions are measured using measuring instruments such as dial gauges that look at the difference between targets and reference devices such as gauge blocks and ring gauges.
Direct measurement’ refers to measuring exactly the thing that you are looking to measure, while ‘indirect measurement’ means that you’re measuring something by measuring something else. For an example of direct measurement is weight, distance.