PID(INPUT 4-20mA OUTPUT 4-20mA)

HELLO 

I AM WORKING ON A APPLICATION WHERE I HAVE TO CONTROL A FURNACE TEMERATURE WITH THYRISTOR CONTROLLED HEATER(4-20mA).

I AM USING A THERMOCOUPLE TRANSMITTER WHICH HAS A 24 VDC AUX SUPPLY AND 4-20mA OUTPUT(FOR TEMPERATURE FEED BACK). WHEN I MEASURE WITH MULTIMETER TRANSMITTER IS SHOWING CORRECT mA OUTPUT. BUT WHEN I CONNECT TRANSMITTER (+) TO CH1 AND (-) TO GND IT IS SHOWING 1.434 mA AND NOTHING CHANGE WITH TEMERATURE.

 

Ganesh Datt Joshi
Ganesh Datt Joshi
7
| 1 1 2
Asked on 12/6/16, 2:39 PM
0
vote
723 Views

I remember having a similar issue where the ma reading didn't change.

It was fixed by putting

Indio.setADCResolution(16); // Set the ADC resolution. Choices are 12bit@240SPS, 14bit@60SPS, 16bit@15SPS and 18bit@3.75SPS.

in the setup code.

Raghuram Shenoy
Raghuram Shenoy
7
| 0 0 0
Answered on 12/6/16, 3:59 PM
0
vote

Hello,please submit code sample.

I am quite sure nothing is wrong in the hardware, I don't know if your test with multimeter is valid after all when connected to input bias.

If you load Industruino sample program you can see readings on display and check actual readings

 

Stefano Giuseppe Bonvini
Stefano Giuseppe Bonvini
47
| 0 0 0
Answered on 12/6/16, 3:33 PM
0
vote

i connect multimeter in series with ch1. multimeter and analog input showing same mA value.

Ganesh Datt Joshi
on 12/6/16, 3:50 PM

Your answer

Please try to give a substantial answer. If you wanted to comment on the question or answer, just use the commenting tool. Please remember that you can always revise your answers - no need to answer the same question twice. Also, please don't forget to vote - it really helps to select the best questions and answers!

Ask a Question

Keep Informed

About This Forum

This community is for professionals and enthusiasts of our products and services.

Read Guidelines

Question tools

29 follower(s)

Stats

Asked: 12/6/16, 2:39 PM
Seen: 723 times
Last updated: 12/6/16, 3:59 PM