Temperature Cycling

I developed this Thermal Test System hardware and software to interface to a customer’s existing equipment, giving them automatic program control of their thermal chamber where the chamber offered no native remote control capability. The system monitors up to eight thermocouple channels, which can be placed on any circuit components, according to the test designer’s requirements. In addition, an oscilloscope monitors two periodic processor signals, which indicate proper operation of the circuit board during thermal cycling.

It was the purpose of this program to provide a course of development and a resulting test system that provided my customer with the greatest possible value. To that end, I provided a system that not only fulfilled the customer’s requirements, but also provides the following extra features:

  • The test system is designed to be controlled by a Test Script, which determines the measurements to be made, and gives the test designer the ability to control the test system’s thermal conditions, using an easily understood text format.
  • In addition to the thermal measurements and Oscilloscope frequency measurements required by the customer, the system provides digital input capabilities that can be used to monitor TTL signals from the circuit board being tested.
  • The system not only provides csv file logging of all measurements, but also an HTML screen shot of the temperature graph as it appears at the conclusion of a given test script.
  • While the original plan for this system required only on/off control of the thermal chamber based on the a target temperature, I provided modulated heat using proportional control around the temperature set point to allow more precise control of the chamber’s temperature.
  • I also performed an in-depth examination of an alternate oscilloscope to see if a four-channel scope could be substituted for the original two-channel scope, without impacting the accuracy or sample rate of the original scope.
  • I developed a complete Operator’s Manual, which was provided as an extra benefit to my customer.

This Thermal Test system is featured in the video at the following link: Roll-2-Roll