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Accuracy on analog sensors

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howie

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Let say an analog water level sensor with voltage output range between 0-5Vac / 0-500ft installed with cable length of 300ft. The sensor outputs a voltage of 2.5V corresponding to an equivalent level of 250ft.

How can I negate the voltage drop due to cable length, cable size, temperature etc. to have an accurate reading.

Are there any circuit to solve this problems?

Or would the voltage drop (in any cable length) be neglible not to affect much on the voltage output?

Thanks!
 

pakitos

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I advise you to do a small test yourself.
But in general the impedance of the wire must be compared to the impedance if the sensor.
What is the sensor you are using?
does it have a datasheet
 

kender

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howie said:
Or would the voltage drop (in any cable length) be neglible not to affect much on the voltage output?
How much current is running through the signal lines of the cable? Probably under 100mA, since it's a voltage output sensor (you can check the sensor data sheet for the max output current). What's the input impedance of the circuit which reads the sensor? Current, resistance of the cable, which you can measure, and Ohm's law will give you the voltage drop. You can convert it to feet and see if it's negligible.
 

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