Resolution refers to the number of bits used to represent an analog
signal on an analog input device.
The higher the resolution which could make the voltage/current range to
be divided finely, could convert the analog value more accurate to the
digital value.
Devices with 12-bit resolution divide the range width by 4096.
If the range of the device is 0 to 10V, the minimum unit of converted voltage
will be 10 ÷ 4096 = 2.44 mV.
If the range of the device is 0 to 20mA, the minimum unit of converted
current will be 20 ÷ 4096 = 4.88 mA.
Devices with 16-bit resolution divide the range width by 65536.
If the range of the device is 0 to 10V, the minimum unit of converted voltage
will be 10 ÷ 65536 = 0.153 mV.
If the range of the device is 0 to 20mA, the minimum unit of converted
current will be 20 ÷ 65536 = 0.305 mA.