Test labs serve an important role in electronic and electromechanical systems by providing certified testing based on national and international standards. D.L.S. Electronic Systems, based in suburban Chicago, has been in business since 1983 and is well-known in the EMC community for its compliance testing. Now, the company has expanded its environmental testing capabilities to include combination temperature/humidity/altitude testing in a single chamber.

“The new chamber lets us test moving parts and lighting for the military,” said D.L.S. engineer Mitch Gaudyn. “We must verify that these parts don’t freeze at cold temperatures. The chamber lets us vary all three parameters at the same time.”

Testing for temperature and humidity at temperatures below freezing presents a challenge. “You need to add moisture without creating snow,” said Gaudyn. He explained that the chamber can spray water that’s warm enough to not freeze until it hits the DUT. Typical low-temperature testing goes down to −20°C (−4°F) for most devices, with some military devices going down to −30°C (−22°F). The chamber can cool to −73°C (−100°F). Its top temperature is 177°C. Pressure can adjust to simulate altitudes to 30,500 meters (100,000 feet).

D.L.S. Electronic Systems A single chamber can adjust temperature, humidity, and altitude (air pressure) for testing mil/aero products. (Image: D.L.S. Electronic Systems)

Although the chamber can monitor and control its own temperature, humidity, and pressure, D.L.S. engineers prefer to monitor the three parameters with external equipment. “Sometimes, we need as many as 20 thermocouples inside the chamber,” said Gaudyn. That lets engineers monitor temperature all around the DUT with calibrated sensors and a data-acquisition system. Thus, there’s no need to calibrate the chamber itself.

Unlike older test chambers, the new chamber uses a tablet computer as its user interface. “It’s easy to operate,” said Gaudyn. In addition, the chamber and external equipment are networked for storing test data.