The modern Telecom Computing Architecture (TCA) standards provide a basis for fast telecommunication applications. In addition, there is significant demand for systems operating under harsh conditions in transportation, industrial, and Mil/Aero applications. The MicroTCA standard offers many benefits for these types of systems: high modularity, a small mechanical form factor, self-diagnostics, and extremely high performance.

However, some modifications are necessary before MicroTCA is used in rugged applications. To avoid creating any incompatibility with the essential features of the existing standard when making the necessary adaptations, the MicroTCA.1 – Rugged MicroTCA Air Cooled Specification and MicroTCA.2 for Conduction Cooling working groups have been formed. In fact, Elma’s team is authoring the MicroTCA.1 Sections 5 (Thermals) and 10 (Test Setup) for the Rugged MicroTCA specification.

Elma’s Ruggedized MicroTCA Solutions

Elma has designed a new MicroTCA chassis is an ARINC 404A Full- Size ATR Long Enclosure, often used in commercial and military aviation. The rugged enclosure features modified front panels that can be secured to the chassis. This provides more protection for shock and vibration. Shock absorbers/dampers can also be added to the enclosure for extra protection. Thermal management can be achieved via either convection or conduction-cooling.

The backplane holds six AMCs, one MCH (MicroTCA Carrier Hub), and one power module. Single modules slots in the full size are standard, but other configurations are possible with the enclosure’s modular design. The compression-mount version of the signal connectors are used. Initial testing was performed on the Ruggedized MicroTCA ATR. Elma is also releasing a COTS 19” rackmount chassis for Ruggedized MicroTCA based on its popular 12R2 product line.

Test Conclusions

Customers interested in the 35-page test report can request a copy from Elma. A highly condensed summary of the results is presented herein:

Testing shows the chassis meets the MIL-STD-810E shock/vibration requirements and MIL-STD-461 for electromagnetic interference. The vibration and shock tests were performed according to the IEC 61587 1 and VITA 47 standards in six axes (three spatial axes, with the system rotated by 180 degrees for each axis).

After each test session, the entire system was inspected for mechanical and electrical damage. An electrical test was performed to check the functionality. For this purpose, the fully configured system was started up. Activation of each card was taken as an indication of the presence or absence of damage.

• All slots started without any errors after all of the sinusoidal vibration tests.
• The slots booted as follows after the random vibration tests: In the X and Y axes: all slots; in the Z axis: two slots did not boot automatically, but they did boot after the cards were pulled and reinserted
• An additional random vibration test with the system operating was performed in the Z axis (Fig. 7). Although the MCH issued a few error messages during this test, it otherwise continued to operate, as did the entire system.
• All slots started without any errors after all of the shock tests.

As a result, it can be concluded that:

• 1. The fixation method selected by Elma was to use screws to secure the AMCs to the system profiles. Mechanical problems did not occur with this form of fixation. Even the load cards fitted with 264-gram weights were held correctly in place. The electrical tests after the vibration tests and shock tests showed that the cards were not damaged, and they fulfilled their functions without any restrictions.
• 2. As a result of theses tests, Elma will introduce special card guides with additional retention functionality in order to enhance operational reliability, especially under harsh conditions.
• 3. Only minor modifications to the standard AMCs are necessary for the solutions proposed in the first two points above. This means that these modules retain the advantages of modularity and suitability for general-purpose use.
• 4. To maintain reliable electrical contact, the AMCs must be secured to the frame for use under ruggedized conditions.
• 5. The plug-and-socket connectors on the backplane and the gold plating of the AMCs must be further refined for long-term use (see below).
• For more information on Elma’s Ruggedized MicroTCA products, contact us at www.elma.com or sales@elma.com