Wong said:

Hi,

Output voltage = Full scale voltage - Zero scale voltage.

Is the term Full scale means no load is connected and Zero scale

means a load is connected (opened), so output will be the difference

of these two ?

TIA.

I have seen these terms used only in reference ot a voltage

measurement process. For instance, an analog to digital converter

measures a voltage by comparing it to that produced by a programmable

voltage divider connected between two reference voltages, full scale

and zero scale. If the measured voltage is equal to or greater than

the full scale reference voltage, the measurement indicates 100% of

the full scale digital value needed to program the divider to select

the full scale reference. If the measured value is half way between

the full scale reference and the zero scale reference, then the

measurement result is a digital value 50% of the way between zero and

full scale. Etc.

On many of the PIC microprocessors, you have the option to connect the

full scale and zero scale terminals of the divider to either the

supply rails (to measure 0 to 100% of output over that range of

voltages) or to connect either or both to some other reference

voltages (to narrow the span of the measurement range to increase the

precision when the input voltage is known to fall between narrower

limits).