Hi, I’ve been using WNK 8010-TT submersible pressure transducers with I2C 3.3V on the MKR NB 1500 to measure tank water levels but find a large number leak then short out. Does anybody know how to read a 24V 4-20mA pressure transducer with an MKR NB 1500 which is powered by a 2000mA battery and usb solar panel?
What hardware is needed to boost 3.3-24v and how to then read mA?
Thanks.
There are plenty of projects reading 4 - 20 mA current loop. Search for Arduino + current loop.
Batteries are described by their voltage and technology. Capacity is unintersting.
Step up from battery voltage to 24 volt. Look for buck boost converters.
Read what mA? Use a current sensor.
You say I2C 3.3V, then you say 4 - 20mA. What is the exact, full part number? How much current does the sensor require besides the 20mA at 24V? Can you post a datasheet?
What does "number leak" mean?
Don’t forget if you boost 3.3v to 24v the current consumption into your converter will be a little over ( 24/3.3) times bigger plus a bit more . Say 160mA .instead of 20mA.
Check the spec of you transducer , you might be able to run it at say 10v ???
Sorry. The MKR NB 1500 runs on a 3.7v lipo plugged into the jst battery connection socket. I can’t find any projects using a 4-20mA sensor with an MKR board.
I’m currently using a WNK 8010-TT submersible pressure transducers with I2C 3.3V. Unfortunately seven(a number) of the sensors have failed as water is leaking past the gland on the cable and wrecking the sensor. I’m wanting to change to a 4-20mA sensor as they are easier to get and hopefully more reliable and use less power than the i2c sensors that I am currently using. I’m unsure though how to boost the voltage from 3.3V to a level that the 4-20mA sensor will operate and then how to read the current draw. What I’m asking is if any one has done this with an MKR board powered by a 3.7V battery.
Thanks Hammy, that’s a good tip. I’ve used a 4-20mA submersible pressure transducer on a 12v project before and from memory I think they most have a range from 9-24v. I’d love some advice on how to wire a 4-20mA sensor to a 3.3v MKR NB 1500 board if anybody has done it. Ideally boost an analogue pin and read the current draw to reduce the power consumption compared to a constantly powered i2c setup.
I believe the MKR NB 1500 has a 0 to 1V ADC, so you would need a load resistor that would yield 1V at 20mA, 50Ω or buy a current / voltage converter that outputs 1V.
51Ω is a standard value, with a 2.4k in parallel would give you 49.94Ω. Close enough?
You need to understand the technic of running the 4 - 20 mA through a resistor and pic up the voltage. Don't hang on to MKR boards. The basic technic is the same for all boards.
Thanks JCA34F. Much appreciated.
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