4-20ma signal (transmitter)

I have gotten the transmitter from this sight wired it with power supply (12v) or (10v)if I grab power from the vfd.
I followed the diagram from this site along with the arduino code. connected it to a multi-meter and it doesn’t work. verified I am getting 5v from i2c. I’m using the arduino mega with the a i2c shield from this site.

Any help would be greatly appreciated.
Thank you

are you using this code

can you share a picture of your setup?


Yes thats the code i’m using. I can measure ohms but not milliamps. I’m am also using a desktop psu for the power for testing.

can you share a wiring diagram ? i would to see how everything is connected.

i ran same setup here and it works as expected.
what does it show on the meter while you read current?
do you have one another meter, if you do can you measure voltage across the screw terminals.

I’m not showing anything on milliamps (0.00) lm not getting anything across the terminals with the other meter. I can read the resistance, and it changes with the code but it won’t do millamps.

when everything is connected it will read the same voltage as the power supply across the terminals.
because meter is connected in series and and will work as a bridge ( make sure you set meter to read milli amps)
is is possible meters milli amp fuse is blown? looks like thats the case. if there is no voltage across the terminals

II was thinking that fuse could be blown as well. I’m not getting anything on either meters. but i’m checking them now.

yep it was the fuse. I there anyway to smooth out the signal so it doesn’t jump around?

i think you have code running in the arduino and its changing the output.

yeah some times the value spikes. but i believe it was an issue with the code. the other issue is the multi meter is displaying half of the the code is outputting.

from this code I found on this site.

you can change this part
for (int i=290; i <= 1500; i++) ///////to use this code with 4-20mA Hardware
and adjust the i values based on your requirements

Will do. You have a lot.
Thank you

I have another issue. The 4-20ma is not changing values anymore. Connection are the same and i uploaded the old code to test it and its still not changing