HALT stands for “highly accelerated life test”, which is a stress test used for determining and accelerating product reliability. HALT tests are generally used in the product development stages for electronic equipment. Data from HALT tests allows testers to identify flaws or weaknesses in the product design.

HASS stands for “highly accelerated stress screen”, which is a production testing screen based on HALT. Both tests utilize processes to determine weaknesses in product design, thus enabling engineers to address these weaknesses in order to increase product reliability.

Typical products undergoing HALT/HASS procedures are cell phones, PDA’s, televisions, printed circuit boards, resistors, capacitors, and diodes. The products are subjected to simulations of environmental stresses in the HALT/HASS procedure that mimic and surpass conditions expected during the use of the product. Conditions in HALT/HASS procedures include temperature cycling, repetitive shock, power margining, and power cycling.


The Spider-H is designed by Crystal Instruments for HALT/HASS applications. The Spider-H modules feature four voltage/IEPE input channels in addition to measurement channels for temperature and humidity. Output channels provide various signal output waveforms to drive an electro-dynamic shaker, hydraulic shaker or pneumatic hammer. Six temperature control outputs and four humidity control outputs create the most powerful HALT/HASS chamber in the world. The Spider-H also features a built-in isolated digital I/O interface. Programmable vibration ramps, gRMS level, and test duration are all synchronized with temperature and humidity control profiles. Typical temperature control is accurate as +/- 0.5 C after stabilization.