News date: 12/11/2006
Compel Electronics presents its solution for ATCA Chassis
A common hardware platform for computer equipment and for telecommunications, allowing all the functionalities that are necessary for applications in telephone exchanges.

Cornate d’Adda, november 2006 - Compel Electronics SpA, www.compel.it, a recognised international company, leader in the design and manufacture of interconnection systems and cable assemblies, presents its solution for ATCA chassis.

Over recent years the Telecom market has opened up more and has become highly competitive;  prices for the various services have been significantly reduced and the Operators have been forced to put pressure on the equipment constructors for greater volumes at reduced costs.
This has led to a growing need for a “standardisation” process, which is appropriate also in the field of telecommunications, as are the  VME (Versa Module Eurocard bus) and CPCI (Compact PCI) standards for other applications.
The new ATCA standard offers an excellent solution to everyone, allowing, at low cost,  extensive fields of application, high density of functions and interchangeability between suppliers.
The Advanced Telecom Computer Architecture (ATCA) standard was introduced by the  PICMG Association (Industrial Computer Manufacturers Group) as PICMG 3.0 in November 2001. The basic specifications of the ATCA were ratified in December 2002.
The ATCA is, therefore, to be considered a common hardware platform for computer equipment and for telecommunications, allowing all the functionalities that are necessary for applications in telephone exchanges.

MANUFACTURING ASPECTS 

The Hardware platform consists of a specific rack which is suitable for housing a combination of electronic boards in quantities of 16 pieces (23” width) or 14 pieces (19” width).
The rack comes complete with special fans to allow dissipation up to 200 W for the allocated signal board, the fans handling and control boards and also the entire alarms and control system.
Thanks to the experience gained over the years in the field of connections for telecommunications and the assembly and testing of backplanes (more than 300,000 pieces supplied since 1989) and thanks to the competence acquired in recent years in mechanical design (completed with specific tools for thermal and EMC analysis), Compel Electronics Spa has developed its own solution for an ATCA chassis which is in total compliance with the reference standards and, where possible, foresees further improvement from the point of view of the mechanical components.
In particular, the manufacturing tolerances for the single elements have been reduced with respect to the standard, with the aim of eliminating any critical aspect within the standard, linked to using the RSS ( Root Sum Squared ) probabilistic method for calculating the coupling tolerances.
Particular attention has been paid to the design of the fan zone, made up of three independent drawers, each with two “ Mixed Flow” type fans, which,  positioned in the lower part of the rack so that the service life (MTBF) is not reduced, generate a light pressurisation on the inside, preventing the suction of dust particles which are particularly dangerous in warm-humid environments.
The rack is, in any case, equipped with an anti-dust filter which can be easily removed / substituted.
All the openings present on the rack comply with the requirements for anti-fire casing given in the EN 60950 standard.
The structure, in accordance with the standard in question, is made of Aluzink sheet and is assembled using rivets.

To avoid the triggering of corrosion, the use of dissimilar materials has been greatly limited and, in any case, the maximum difference in potential between the parts making up the rack is 0.30 Volts, or 30 V/100 if referred to the anode index.
During the design project, particular attention has been paid to the important aspect of thermal dissipation, which has been checked using specific thermal analysis tools, such as Flotran (Ansys), Flotherm (Flomerics), Flopack (Flomerics).
The same care has been dedicated to reducing Electromagnetic Interferences (EMI), eliminated through using shielding elements, low resistivity contact zones and reduced pitches between rivet points.  For the mechanical structure alone, the solutions adopted have led to the achievement, with ample margins,  of “Performance level 2” (and very close to Level 3)  as per the  IEC TS 61587-3 “Electromagnetic Shielding Performance Tests For Cabinets, Racks and Subracks”.
The rack is completely fitted out with the common items provided for by the ATCA standard:
Backplane complete with specific connectors and checked from the point of view of “Signal Integrity”, Fan Boards, PEM boards, ShMC boards.  When fully equipped, it has been further checked to ensure its compliance regarding conducted interferences according to Class B as laid down in the CEI EN 55022 standard “Equipment for information technology.  Radio disturbance characteristics.  Limits and measuring methods”.

Technical specifications

· In compliance with PICMG 3.0
· 16 positions
· Double supply module (PEM)
· Double control module (ShMC)
· Three fan drawers
· Front and rear channels for cables
· In compliance with  ETSI and NEBS standards
· RoHS and WEEE compatible materials and finishes

      Coordinate Dimensions
· 12 U (533.4)   Height
· 535 mm         Width
· 390 mm         D1 Depth (Front / Front)
· 470 mm         D0 Total depth (including cable channels)

    Dispersable Power :
· 200W for front board
· 5W for rear board (RTM)

     Access :
· From front and rear
- front : Fan drawers, Boards, Air filter, Cables channel
- rear :  RTM boards, Cables channel,  PEM Boards,  ShMC Boards

  Thermal : 
· N° 6 “Mixed flow” fans

     Safety :
· EN 60950

     Environment :
· GR 63-CORE, ETS 300 019 class 2.2, 1.1, 3.1
· ETS 300 753 class 3.1

    Rack :
· According to ETS 300 119-4, ETS 300 119-5
· Modifications are possible on request

    Recommended Cabinets :
· According to ETS 300 119-3 or 23”