Thermocouple Signal Simulator

Sponsor: Emerson- Kent Burr, Charles Eastberg

Advisor- Dr. Semih Aslan

Group: NPPH(1.7)Taylor Nash, Rey Perez, Victor Pinones, and Travis

Howell

Why Emerson Needs A Thermocouple Signal Simulator

❖ Emerson has three different test teams in Round Rock

❖ They do different types of component testing, maxing out, and configurations

❖ Thermocouples is a very common component they test

❖ They want to be able to simulate thermocouple readings

❖ What does the Thermocouple Signal Simulator do?

Options❖ Input

➢ Multiple inputs➢ Configure thermocouple

types■ Input on DIP switches■ Software implemented

❖ Output➢ Have multiple outputs➢ Have just one output

Dataflow❖ Hardware implemented

➢ Need 8 of each components, one for each of the thermocouple types

➢ Too costly for hardware set up- not enough space, too many bugs

❖ Software implemented➢ Only need one processor

Components❖ Hardware

➢ Arduino Mega 2560➢ DAC, ADC➢ Electrical Isolator➢ 5V power supply➢ 4-20mA input➢ Power resistors➢ Op Amp➢ Printed Circuit Board

(PCB)

❖ Software

➢ Program to execute all logic and arithmetic

➢ Thermocouple Polynomial Library

➢ Thermocouple look-up tables

Proposal❖ Input

➢ 4-20mA, provided by Emerson

❖ Project: convert the 4-20mA signal into an isolated mV signal ranging from ±100mV

❖ Combination of mostly software and some hardware

❖ Configuration to each type of thermocouple

➢ 8 synchronized output nodes

Demo: Dataflow

Input4-20mA

Input range percentage conversion

Find relative temp. for

thermocouple

Use temp. for “look-up”

value

Map to PWM port

range

Output

BudgetDevice

Price

❖ Arduino Mega 2560.……………...$40❖ 5V High/Low Opto-isolator……....$8❖ PCB by TXST………………...…...$0❖ 24 bit ADC…………………………$11❖ 20 bit DAC ………………………..$20❖ 1-8 demultiplexer………………....$5❖ Project houseing………………....TBA

Total Estimated Price:$84

$200/memberTotal: $800

Test Plan

❖ Overview

➢ Input 4-20 mA signal

➢ Convert and isolate the input to eight ±100 mV outputs

➢ Outputs run to Emerson’s CHARM systems

Constraints❖ Economical

➢ Hardware implementation would be costly

➢ Wasteful of resources, i.e. all hardware would result in multiple components

➢ Processor/software implementation was much more practical

Dataflow Schematic Output Isolation

Hardware Selection

Hardware Purchase

Hardware Purchase

Timeline

Timeline

Program

DebugCircuit Assem

bly

Testing Softwar

e

Circuit Testing

System Testing

WriteProgram

CircuitAssembly

Deviation Handling

TestingSoftware

VerifySystem

Demo and Progress❖ Our demo simulates the type T thermocouple

❖ Input from Arduino’s serial interface

❖ Outputs analog signal on PWM port

❖ Similar to our completed system, except no isolation

References❖ htatp

://community.emerson.com/cfs-file/__key/communityserver-blogs-components-weblogfiles/00-00-00-02-92/3581.emerson_5F00_electric_2D00_logo.jpg

❖ http://upload.wikimedia.org/wikipedia/en/e/ed/Thermocouple_%28work_diagram%29_LMB.png

❖ http://www.ti.com/graphics/folders/partimages/ADS1675.jpg

❖ http://www.vetco.net/catalog/images/VET-SP-DIP3-1.jpg

❖ http://media.digikey.com/Renders/~~Pkg.Case%20or%20Series/DIP16_SOT38-1%20Pkg.jpg

Questions?