State of Our Knowledge

Let’s summarize what we’ve learned so far:

1. We’re designing a control system for a soldering iron.

2. We have to keep the iron temperature at 300o F +/- 10o.

3. We’ve learned a bit about Agilent Vee, thermocouples, and relays.

What We Don’t Know

• What we don’t know can be summed up in a serious of questions:

• Why 300o F ? • How hot do soldering irons get? • At what temperature does solder melt?• How long does it take a soldering iron to

heat up?• Can we model this behavior?

Additional Memo Required

• Since we’ve discovered that there is a discrepancy with the temperature being measured in Fahrenheit or Centigrade…

• Write your Prof. a memo with information detailing your research in this area and include your recommendations.

Your Task

1. Design an Agilent Vee program to capture the voltage from a J thermocouple.

2. Convert the millivolt reading from the sensor into temperature readings.

3. Plotted this information in Excel.

4. Use Laboratory Exercise #7 as a guide

First Difficulty

We need to figure out a transducer equationa. Use data sheet for a J thermocouple that the professor

handed out last week. (use about 10 data points selected from the entire range)

b. Plot the temperature rise as the voltage output increases for the sensor in Excel.

c. Use the chart wizard to plot the graph.d. From the main menu, pull down on Chart and then

click on Add Trendline.e. Determine the formula you’ll add to Agilent Vee.

Suggestions

• Divide and conquer. You can figure out the transducer equation as homework. On Friday, the equipment will be available to us.

• Consult with each other, other teams, and the professor.

More Suggestions

• You could just collect the millivolt readings and have Excel implement the conversion to temperature.

• The formula seen in the Lab (2nd formula box) is useable, just not verifiable.

Communicating the Design

• Step 8 of the Design Process means:• Do the Lab Report for this exercise.• Include the usual paperwork associated with

Agilent Vee. • Make liberal use of your journals to record

what you are doing, conclusions formed, mistakes made, errors corrected, and successes.