Final answer:
To find the temperature that corresponds to a current of 7.68 mA, a linear interpolation is used based on the given calibration, resulting in a temperature of 23℃. Current signals are preferred over voltage signals for analog transmission due to their robustness against signal loss and interference.
Step-by-step explanation:
To convert the current value of 7.68 mA to the corresponding temperature, we must establish a linear relationship based on the provided calibration. The calibration indicates that 0℃ corresponds to 4 mA and 100℃ corresponds to 20 mA. We can use a simple linear interpolation to find the temperature for the actual current of 7.68 mA:
- First, find the range for the current: 20 mA - 4 mA = 16 mA.
- Next, find the current's position within the range: 7.68 mA - 4 mA = 3.68 mA.
- The proportion of the current within the range: 3.68 mA / 16 mA = 0.23.
- Now, apply this proportion to the temperature range: 0.23 * 100℃ = 23℃.
The temperature corresponding to 7.68 mA is therefore 23℃.
We prefer current signals to voltage signals for analog transmission because current signals are less susceptible to signal degradation due to resistance in the wires and connections, and to temperature variations in resistance, which is particularly important over long distances or in electrically noisy environments.