Mezzanine boards for AdvancedTCA

A Schroff product story
More from this companyMore from this category
Edited by the Electronicstalk editorial team Nov 10, 2005

AdvancedMC (AMC) modules contain additional boards, which extend the function of the carrier board considerably.

AdvancedMC (AMC) modules contain additional boards, which extend the function of the carrier board considerably.

They create a serial interface for the carrier board, support hot swap and offer a software interface for the board management.

Individual WAN interfaces for the board management can for instance be swapped during operation, without the extraction of the entire carrier (with interface modules) from the system.

The carrier board can be a simple passive board or it can be a so-called single board computer.

The AdvancedMC modules are inserted from the front like 19in plug-in units parallel to the carrier board.

The contacts are not arranged as connectors, but as pads on the board; this provides better signal quality for high transfer rates at the crossover between AdvancedMC module and the carrier board.

Depending on the number of contacts one differentiates between AdvancedMC modules Half Height (HH) and Full Height (FH) as well as Single Width (SW) and Full Width (FW).

The AdvancedMC architecture is very flexible and supports a number of transfer protocols with different band widths.

In comparison to the 19in standard, there is a significant difference to the AdvancedMC standard, which can lead to confusion.

Therefore to begin with a short explanation: With conventional 19in plug-in units, which are installed vertically in a system, the measurements in a vertical direction are called height, the horizontal measurements are the width.

With AdvancedMC carriers and modules this is the complete reverse.

Here the standard defines the units in a lying position and not in the assembled state, for example the width of the 19in plug-in unit becomes the height for AdvancedMC plug-in unit, the height of the 19in plug-in unit becomes the width for the AdvancedMC plug-in unit.

In order to facilitate understanding, in the following text the AdvancedMC plug-in units are talked about in an assembled state and the horizontal measurements, analogueueueueueue to 19in plug-in units are the width and the vertical measurements are the height.

The central components of the AdvancedMC structure are module mechanics and the so-called carrier.

The module mechanics are geared to the aforementioned module versions (SW-HH, SW-FH, FW-HH, FW-FH).

The mechanics are based 100% on the AdvancedMC standard and are strictly regulated.

At the top part of the U-shaped front panel, made from 0.65mm stainless steel, a die-cast part with a fourway light pipe is integrated to signal the operating status.

In the bottom part of the front panel in the same position the locking mechanism is located.

On the left hand side of the front panel and at the bottom is a continuous EMC seal and the module board is screwed to the rear.

The locking mechanism with hot swap functionality works in three stages.

In the first position (fully inserted) the AdvancedMC module is locked and the optional micro switch is closed.

In the second position (3mm extraction) the micro switch is open, but the plug-in unit is still locked.

Only in the third stage (6mm extraction) is the plug-in unit unlocked and can be taken out of the carrier.

During insertion of the plug-in unit it is unimportant what position the handle is in.

During insertion the handle is positioned in the correct location in order to achieve the corresponding function.

Additional fixing of the plug-in unit is not planned and it is also unnecessary.

For the individual configuration of the front panel (cut-outs for connectors, switches, screen printing etc) this is assembled separately and can be retrofitted.

For this Schroff offers their front panel service even for smaller numbers of the AdvancedMC modules.

The AdvancedMC module mechanics are supplied by Schroff as a complete kit.

The carrier can be compared with a small cassette, in which the AdvanceMC module is inserted.

The carrier itself is hotswapable and, like a plug-in unit, it is inserted into the AdvancedTCA system, whereby the dimensions of a one-slot AdvancedMC carrier are identical to that of an AdvancedTCA plug-in unit (8U, 6HP).

To secure the carrier in the system, the same components, screws, locator pins etc.

are used.

Therefore at a first glance the AdvancedMC carrier plug-in unit cannot be differentiated from a normal AdvancedTCA plug-in unit.

The standard defines three different versions of the carrier: the Conventional Carrier, the Cutaway Carrier and the Hybrid Carrier.

The basic construction and the dimensions are the same, the differences show themselves in the configuration of the carrier board.

With the Conventional Carrier the carrier board is continuous from the front to the rear and allows complete assembly of components.

Only Full Height (FH) modules can be used here.

The assembly height of the module board is limited to 10.55mm.

With the Cutaway Carrier the board is cut out in the area of the module.

Therefore two Half Height (HH) modules can be used next to each other.

If a Full Height module is used, the assembly height of a FH module board is 22.45mm.

The Hybrid Carrier in principle is a Cutaway Carrier, which has not been assembled to its full height with AdvancedMC modules.

Depending on the assembly, the front panel has to be extended at the top or bottom.

The corresponding mechanics can be configured at request.

The carrier mechanics for the Conventional and Cutaway Carrier are identical and consist of 0.6mm thick stainless steel panels, where the inside surfaces have been completely electrically insulated, the outside surfaces are covered with a removable protective foil.

The distance between the sheets is defined through specific die-cast parts, so-called struts, which, with their plastic extensions, serve as guides for the AdvancedMC modules.

EDS clips are integrated into these struts, in order to create a conductive connection between the board, the AdvancedMC modules and the Carrier.

In a carrier, depending on the arrangement of the struts, AdvancedMC modules in different combinations can be inserted.

With a Cutaway Carrier for instance eight SW-HH modules or two FW-FH modules and other combinations can be inserted.

Even retrospectively the previously assembly struts can be replaced by a different version, in order to change the assembly possibilities with different AdvancedMC modules in the carrier.

If the entire carrier is not assembled with AdvancedMC modules, the vacant slots have to be filled with "blank" modules.

These AdvancedMC blank modules are constructed like AdvancedTCA standard modules, however, without light pipe and with an unassembled board.

As the air circulation in the system is effected by the vacant modules, specific so-called 'air baffles' are mounted and the air throughput is therefore regulated between 60 and 80%.

For the insertion and extraction mechanics, respectively the locking of the carrier, two handle versions are available.

The standard handle with an opening angle of 75 degrees for insertion and extraction in one action requires a pivoting range of 23mm above or below the dividing line.

This extraction handle is almost identical to that of the AdvancedTCA plug-in units.

The only difference being; the handle in its idle position is not in a vertical, but in a horizontal position, so that it does not collide with that of the AdvancedMC module.

In order to activate the micro switch the handle is pushed in a horizontal direction.

As described in the AdvancedTCA standard, the micro switch is locked when turned by 1 to 9 degrees.

Through an integrated spring, the handle will always return to its idle position.

Therefore unintentional operation of the micro switch is impossible.

In its idle position the handle can be moved up or down by 90 degrees avoiding any obstruction.

The second handle version, the so-called MF handle, is used, when additional components, such as cable trays or further Advanced TCA systems with integrated carriers are installed above or below the AdvancedTCA systems.

Then there is often not enough space available for the insertion/extraction in one move.

The MF handle too has an opening angle of 75 degrees, however, the insertion/extraction is in three stages via two changeovers, comparable to a ratchet.

The bottom limit respectively upper limit of the carrier during insertion/extraction is not exceeded.

Schroff offers the entire carrier mechanics for the AdvancedMC product range as standard and also the front panel service (cut-outs, screen printing, assembly etc).

This means, that customers can obtain the entire AdvancedTCA mechanics, from the AdvanceMC module to the AdvancedMC carrier to the entire wired AdvancedTCA system from one source, which will increase the system reliability.

The AdvancedMC modules should find application areas outside the AdvancedTCA area in future.

For this reason the PICMG has formed a new standard group, which will involve itself with a standard for the MicroTCA.

This concerns the definition of subracks, backplane and shelf management for the assembly of AdvancedMC modules.

The MicroTCA standard is expected to be issued at the end of 2005.

Schroff is responsible for the mechanical part of the standard.

Send to a friendSend to a friend

Not what you're looking for? Search the site.

Back to top Back to top

Google Ads

Contact Schroff

Contact Schroff

Related Stories

Contact Schroff

Newsletter sign up

Request your free weekly copy of the Electronicstalk email newsletter ...

A Pro-talk Publication

A Pro-talk publication