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I would like to be able to read values of two thermal couples and a pressure gauge using my raspberry pi. Recording the data and then sending it to a server at the end of the day.

I am using dual t/c thermal couples. Link for the them. https://www.omega.com/en-us/sensors-and-sensing-equipment/temperature/sensors/thermocouple-probes/p/ICIN-DUAL

I wanted to use this pressure sensor: http://www.revrobotics.com/rev-11-1107/

I was going to use a Raspberry Pi B with a breakout board: To read each value of voltage and then calculate real values in the code.

This breakout board: https://store.ncd.io/product/3-channel-4-20-ma-current-loop-receiver-16-bit-ads1115-i2c-mini-module/

If anyone can explain to me a better way to do this. I would be happy to listen I am confused on the breakout board because the board only has two connections per channel.

Max
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1 Answers1

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Question

  1. Read 2 thermal couples and 1 pressure gauge using Rpi

  2. Record data and send it to server

  3. A better way to do this?

Answer

I skimmed the datasheet of your thermal sensor, pressure sensor, and current loop receiver module. My first impression is that they are all mission critical, industrial equipment.

Electrical characteristics of 3 pieces of equipment

  1. Thermal sensor: 4 thermal conducting wire, 4~20mA current loop

  2. Pressure sensor: power = 5V, signal output = 0.5V to 4.5V

  3. ADC module: INA196/ADS1115 based current/voltage ADC

Rpi to ADC module Interface Summary

  1. Communication protocol: I2C

  2. Programming languages (suggestion): python, C/C++, NodeJs, NodeRed

Advice / Warning to Rpi I2C ADC (INA196/ADS1115) newbies

I am new to building things like this and guess I just got confused. So for the pressure sensor I can just ignore one of the cables? Using the ground and signal cable. – Max 5

Well, your above comment worries me "a bit". During last couple of months I have been playing as an electronics/programming hobbyist, the hardware/software related to your project: current loop sensors including INA221, ADC including ADS1115, ...

The current sensor INA219 and voltage ADC 16 bit ADS1115 used in you project has a rather steep learning curve for newbies. You might like to first read the following posts on using these devices, to get a feeling of how hard it is. If you indeed found it scary, then I can recommend two simple devices ACS712 (current sensing and ADC combined, saving trouble for newbies) and PCF8591 (ADC, but 8 bit only). You can use these newbie friendly devices as a warm up exercise, before researching on you more advanced, industrial grade equipment.

Reading Voltage Input on ADC [using ACS712 and INA221]

Raspberry Pi Current & Voltage Sensors [using INA219/INA226, ACS712, ADS1015/ADS1115, ADS1256/AD7190]

/ to continue, ...

References

Dual Element Thermocouple probe with Standard Size Connector

Specifications

Two Sensor Readings Allows Two Readings of a Single Point

Continuous Monitor and Control & Built-in Backup

Analog Pressure Sensor

Specification

Typical Supply Voltage: 5VDC

Output Voltage Range: 0.5 – 4.5VDC

3-Channel 4-20 mA Current Loop Receiver 16-Bit ADS1115 I2C Mini Module

Features

3 Channel 4-20 mA Current Loop Receiver

3-Channel Input with 16-Bit Resolution

4-20mA Industrial Sensor Monitoring

INA196 Current Shunt Monitoring

Ideal for Sensor and Instrument Monitoring

ADS1115 16-Bit Analog to Digital Converter

Onboard 16V Voltage Supply (Boosted from 5V)

Ideal for Industrial Automation 4-20mA input

tlfong01
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