Readings on the dials: 'No data' VS '0' what is the difference?

Readings on the dials: 'No data' VS '0' what is the difference?

Various data is displayed in Aircloud via dials. Sometimes a dial shows 'no data', but in other situations it shows a value of '0'. What is the difference between the two?
 VS 

Before explaining this difference. It is helpful to understand how an Airmatics device obtains data, and displays it on the Aircloud dials. To learn more about how this works, consult this article.

NO DATA
  1. Analog inputs
    1. If an analog input is configured as a milliamp type, it expects to read a value between 4mA - 20mA. If the analog input detects a value different from this range, it will return 'no data'.
      1. E.g. when no sensor is connected to the analog input.
      2. E.g. when a sensor is defective (returning no data at all).
    2. Any analog input, temperature reading, pressure reading, current reading, ... will display 'no data' if they meet the above conditions.
  2. Obtaining info via a reading over a serial communication (e.g. ModbusRTU)
    1. E.g. an incorrect register is read, returning a value that the Airmatics device does not understand. (E.g. strange characters)
    2. E.g. a register is read, returning an obscure value. (E.g. a negative value where one can not be negative)
  3. No function is allocated to the inputs.
    1. Upon configuring the Airmatics device, each input has to be assigned a dedicated function. To allow analog input 1 to read the outlet pressure, it has to be allocated this specific role.
    2. When the input is not correctly configured, the returned value will also be 'no data'.
A VALUE OF '0' IS DISPLAYED
  1. A value of '0' can only be displayed if the analog input is working "correctly". At this point, any value between it's dedicated mapped range could be displayed.
  2. In other words, a value of '0' will only be displayed if the input is actually detecting / reading a value of '0'.
    1. A 4mA - 20mA pressure sensor is mapped to measure a pressure range of 0bar - 16bar.
    2. The dial will display '0' if a value of 4mA is applied to the analog input.
EXAMPLE
  1. My compressor is off. No power is applied to it.
    1. The 'Power In' dial displays a value of '0.00KW'.
      1. This is because the CT's, connected to the devices are returning a value of 0mA. (Secondary range of CT's are usually 0mA - 100mA)
    2. The 'Power In' dial displays 'no data'.
      1. This is because there are no CT's connected to the Airmatics device.
      2. Or, because the CT's are incorrectly connected / wired.
      3. Or, because they are defective.