www.ERNI.com/contact/ Catalog E XXXXXX 01/05 Edition 1

ERNI

Pre-Alignment Modules

Provides reliable connection, coding and grounding of plug-in cards

ERNI has developed a solution to the dilemma posed by high

pin-count hard-metric (HM) connectors and the need for preci-

sion connector mating combined with sufficient play between

subrack guide rails and printed-circuit board (PCB) cards. The

answer is ERNI’s pre-alignment module.

According to the IEC 61076-4-101 standard, a 2mm HM con-

nector may have hundreds of contacts. At the same time, the

plug-in board connectors and backplane connectors must mate

precisely in order to avoid damage. On the other hand, there

must be play between the cards and rails to avoid compression

stress on the PCB.

ERNI’s pre-alignment module consists of solid metal guides

and new guiding systems that offer several optional functions.

For example, there is a kit available with an integrated socket

for HM “coding” keys. Thus no coding on the connector side is

needed, which offers more room for signal contacts. In addition,

there are flattened pre-alignment pins designed to match their

mating connector counterparts. Using an octagonal pattern, it

will support eight additional coding options.

A further reasonable additional option is the electrical contact

model. Shielding is low restistant because of gold plating,

and therefore allows electric current to flow with 40A at 20°C

through a large diameter. A corresponding derating curve is

available. This large pin diameter enables a wide capture range

of >2mm. The PCB is adequately centred and guided as a

result of the appropriate length.

The pre-alignment pin with fastening thread is fastened on the

backplane and is available for PCB thicknesses of 2.5 to 6mm,

and 6 to 8mm. The guide bush is mounted on the daughter

card with an M4 or M5 screw. The PCB thickness for the

daughter card can be 1.6 to 3.5mm, or 3.5 to 5.5mm.