The output of that sensor is an industry standard "4-20mA" (known as a current loop). That means that the current output from the
+S wire varies between 4mA and 20mA depending on the pressure. You need to convert that current into a voltage so that the Arduino can sample it.
Note that your attempt at a schematic is completely backwards. You must connect the +24V pin to +24V on a power supply. GND must be connected to GND on the power supply, and also GND on the Arduino.
Now for the signal. Yes, a resistor is the simplest way of converting a current into a voltage. Simply pass the current through the resistor to ground and a voltage will be dropped across it.
According to Ohm's Law, V=IR. Or, to turn it around, R=V/I.
Your maximum current is 20mA (0.02A) and your desired maximum voltage is 5V. So you can put those values into Ohm's Law and get a resistance:
Now 250Ω resistors aren't that common, but 220Ω ones are. So what would that give us?
- V = IR = 0.02 * 220 = 4.4V
Perfect. And at the lower (4mA) end of the range?
- V = IR = 0.004 * 220 = 0.88V.
So with a 220Ω resistor you would get a voltage reading of between 0.88 and 4.4V on the Arduino.
(Note: the datasheet recommended 100Ω would be more suitable for a 3.3V Arduino - it would give between 0.4V and 2V).
For safety I would also include a small inline current limiting resistor and 5.1V zener diode. If the 220Ω resistor should fail or become disconnected you would get the full 24V (or somewhere about there) across the Arduino's A0 pin. It's limited to 20mA so may not be a problem, but you can't be sure, so best to add that to clamp the voltage to a maximum of 5.1V. After all, a zener diode is cheaper than a new Arduino.
And to clarify - the schematic:
simulate this circuit – Schematic created using CircuitLab