Hello I am currently wiring two pressure transmitters and wanting to read their outputs using my Arduino Uno. I understand two of the four wires are used to read the signal, but which one do I connect to the Analog In pin of the Arduino?
The output of the sensor is 0.5-4.5 Vdc.
Please post a link to the product page or data sheet.
The connections to the Arduino would be GND and Sensor Signal Out to Analog In.
4851R4 Pressure Transducer Sheet.pdf (emerson.com)
So would the black wire go to ground and the white wire would go to Analog In?
That looks correct. Power the sensor by connecting the red wire to Arduino 5V output.
I connected everything like this except just to see the output, I used a multimeter to check what the signal coming out of the white wire was instead of connecting it to the Arduino. I am getting a reading of 0.48 V from one transmitter and 0.5 V from the other. As this is a ratiometric sensor, those values correspond to 0 psi. My system is charged with nitrogen at 70 psi (done by a contractor for a leak test) right now so I know the value I am getting is wrong. What could be the issue?
What makes you think that, and why would it matter? The supply voltage is required to be 5V. Perhaps you mean "proportional".
Which of the six sensors described in the data sheet do you have?
Test the sensor without the nitrogen charge, and then with.
I have the 800-2100 (0 to 100 psi) and the 800-2500 (0 to 500 psi) ones. The output of these sensors is 0.5 to 4.5 Vdc and I said its ratiometric because the 0.5 - 4.5V range corresponds to the pressure range of the sensor (0-100 psi or 0-500 psi). So if I'm getting a measurement of 0.5 V, that corresponds to 0 psi on both sensors. If I am getting a reading of 0.5 Vdc do you think I have set something up wrong?
I won't be able to fully evacuate the system as we need an inert gas in there but maybe the next time the contractor comes in, I can ask him to change the pressure of the nitrogen inside. I do think I am having bigger problems though and have no clue why it's showing up as such 0 psi.
Ratiometric usually means that the output of the sensor is a voltage proportional to the power supply voltage (and the sensed input parameter). Since for this sensor the power supply voltage must be 5V, the term ratiometric does not apply.
If you are powering the sensor with 5V and measure ~0.5V on the output, and it is functioning correctly, it is seeing atmospheric pressure on the input (0 PSI, relative to atmospheric pressure).
Note: the manufacturer should have stated whether this a gage or absolute sensor. I assume gage.
Black to GND, White to analog input pin. Red to +5 (NOT from Arduino), clear to chassis ground (optional).
Nonsense.
15mA is ok.
Didn't know spec, was used to overcurrent figured it was good advice! LOL
Must come from the Arduino.
Supply of a ratiometric sensor must be the same as Aref of the A/D,
If not, you don't have supply error compensation.
This statement is probably wrong.
It should be: 10% to 90% of the supply.
Leo..
There are 6 different versions, 100 ~ 2000 PSI, which ONE do you have?
I have the 800-2100 (0 to 100 psi) and the 800-2500 (0 to 500 psi).
I am just basing this from the datasheet
Do you think the fact I am getting a reading of 0.5 Vdc (corresponding to 0 psi) means I might be hooking things up wrong?
But shouldn't it be reading 70 psi? As that is the pressure of the nitrogen in the pipe?
When first hooked up without pressure, 0.5V for 0 PSI is right.
Yes, it should, if the pressurized nitrogen is even reaching the sensor. Since you haven't tested the sensor under other circumstances, it is anyone's guess what might be wrong.
