Missing RDM pararameters - E1.20 RDM (Remote Device Management) Protocol Forums

ericthegeek · July 15th, 2010

Playing devil's advocate for the sake of discussion:

The units in table A-13 "Sensor Unit Defines" are all derived from the SI Base Units (Meters/Kilograms/Seconds). In this system, a percentage is a unit-less value, thus UNITS_NONE is the most technically correct.

A percentage is unit-less because it is the ratio of two values with the same units. Thus the two units cancel out resulting in a dimensionless value.

For a fog fluid sensor, you could define a SENS_VOLUME with UNITS_NONE and a description string of "Fluid Level (percent)"

este_ · July 16th, 2010

Eric,
you're absolutely right and I agree and disagree at the same time. Then, as you put it, "a percentage is unit-less because it is the ratio of two values with the same units" the mathematically correct result would always be less or equal 1 (not 0...100!).
I'd call this correct, but being a workaround, and not just user-friendly.

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July 15th, 2010	#1
ericthegeek Task Group Member Join Date: Aug 2008 Posts: 390	Playing devil's advocate for the sake of discussion: The units in table A-13 "Sensor Unit Defines" are all derived from the SI Base Units (Meters/Kilograms/Seconds). In this system, a percentage is a unit-less value, thus UNITS_NONE is the most technically correct. A percentage is unit-less because it is the ratio of two values with the same units. Thus the two units cancel out resulting in a dimensionless value. For a fog fluid sensor, you could define a SENS_VOLUME with UNITS_NONE and a description string of "Fluid Level (percent)"

July 16th, 2010	#2
este_ Junior Member Join Date: Jan 2010 Location: Germany Posts: 24	Eric, you're absolutely right and I agree and disagree at the same time. Then, as you put it, "a percentage is unit-less because it is the ratio of two values with the same units" the mathematically correct result would always be less or equal 1 (not 0...100!). I'd call this correct, but being a workaround, and not just user-friendly.