Why use 4-20 ma why do not 0-20 ma

Question

Accepted Answer

4-20 mA is commonly used because it allows for a minimum value of 4 mA to indicate a fault condition, while 0-20 mA does not have this capability.

4-20 mA provides a clear indication of a fault condition by having a minimum value of 4 mA.
Using 4-20 mA allows for a wider range of measurement values compared to 0-20 mA.
Many instruments and control systems are designed to work with 4-20 mA signals.
4-20 mA signals are less susceptible to noise and interference compared to 0-20 mA signals.
The 4-20 mA standard has been widely adopted in industrial applications.
Example: In a temperature measurement system, a 4 mA signal could indicate a fault condition such as a broken sensor.
Example: Using 4-20 mA allows for a temperature range of 0-100 degrees Celsius to be accurately measured.

Accepted Answer

Ensure the right cable and prosess mitter

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