Hi,
I bought a pressure sensor to measure water level in a tank (1-5 metres). The sensor requires 24V DC and it modulates the current in the range 4-20mA, according to the pressure reading.
In regards to how to interface it with the Picaxe I was thinking of putting the sensor in series with a 250 ohm resistor and measure the voltage drop across the resistor (from 1 to 5V) with the DAC of the Picaxe. This would require supplying the sensor + resistor with 29V, which seems non-standard. Also the voltage supply would need to vary according to the reading, to avoid overloading the sensor (If I provide 29V and the pressure is low, then the current is low so the voltage drop across the resistor and the sensor will see more than 24V)
Is this the way it is done, or there are other ways of doing it, like with a much smaller resistor and then by amplifying the signal before sending to the DAC?
Any pointers would be appreciated.
Thanks
Riccardo
I bought a pressure sensor to measure water level in a tank (1-5 metres). The sensor requires 24V DC and it modulates the current in the range 4-20mA, according to the pressure reading.
In regards to how to interface it with the Picaxe I was thinking of putting the sensor in series with a 250 ohm resistor and measure the voltage drop across the resistor (from 1 to 5V) with the DAC of the Picaxe. This would require supplying the sensor + resistor with 29V, which seems non-standard. Also the voltage supply would need to vary according to the reading, to avoid overloading the sensor (If I provide 29V and the pressure is low, then the current is low so the voltage drop across the resistor and the sensor will see more than 24V)
Is this the way it is done, or there are other ways of doing it, like with a much smaller resistor and then by amplifying the signal before sending to the DAC?
Any pointers would be appreciated.
Thanks
Riccardo