understanding the vpx redi

Understanding of REDI

Kamal Raj Krishnan

AGENDA

INTRODUCTION To REDI

FORM FACTORS

INTRODUCTION - Air Cool Design

Design Considerations

Important Rules to remember

INTRODUCTION – Conduction Cool Design

Design Considerations

Important Rules to remember

Any Questions..

INTRODUCTION - REDI REDI is the Mechanical specification of ruggedized electronics system

and it is defined by VITA48 Standard.

REDI – Ruggedized Enhanced Design Implementation

This REDI standard defines the mechanical design Implementation for Plug in Units in VPX system Environment

REDI defines Various Thermal Management Mechanical Design implementations namely the Air Cooling, Conduction Cooling, Liquid Cooling based on classified standards VITA 48.1, 48.2, 48.3..

REDI defines two types of Plug In Units namely TYPE1 and TYPE2

TYPE1 Plug-In Units are compatible for handling in 2 Level Maintenance Environments where TYPE2 Plug-In Units requires required precaution in handling

Primary Difference between TYPE1 & TYPE2 units is the presence of External covers

REDI supports the 0.8”, 0.85” and 1.0” Pitch Plugging on Back Plane

REDI – FORM FACTORS

REDI recommends two Board Sizes as 3U [100mm X 160mm] and 6U [233.35mm X 160mm] for circuit Boards & plug-in units with AIR or Conduction cool mechanism

The base Mechanical specifications of PCB & Plug-In units are defined by VITA46

The Allowable Standoff Height for PMC/XMC is 10mm where 0.8” & 0.85” plug-in unit scheme. It is 12mm where 1.0” pitch Plug-in unit scheme. In this Sufficient Package area to be planned for protective cover for TYPE1 Card

REDI – Introduction to Air Cool Mechanism

REDI Air cool mechanism defined by VITA48.1 standard specification For Conductive elements such as Frame Covers - Need not to connect to PCB electrically except connecting to Safety Ground

REDI –Air Cool Mechanism

This STD VITA48.1 defines Minimum PCB thickness as 0.06”

It defines the mechanical interface specifications of components namely Main PCB, Main Frame, PMC/XMC, PMC/XMC Cover, and Secondary cover as it is indicated in the Image

For main board Connector Protection, Primary Cover, PMC/XMC Cover and Secondary cover can be extended up to connector Edge


Cover Thickness & extension specification is indicated in following table

NF – Not Feasible, FwR-Feasible with Risk, F-Feasible


3U Air Cooled Plug-in Unit – Form factors


Primary side Cover provides following

Accepts PMC/XMC and Cover for PMC/XMC

EMC Compatibility & ESD Protection

Maintains the managed Air flow paths in air-cooled applications

Can contain Insertion / Extraction Features

Secondary Side Cover provides following

EMC Compatibility & ESD Protection

Provides protection for secondary side components

Maintains the managed Air flow paths in air-cooled applications


Secondary Side Cooling should be carefully evaluated particularly for 0.8” & 0.85” because of limited Gap between Secondary cover to PCB. This is likely to be High Pressure Flow path where cooling air requirements are high

Component Layout can be critical to proper plug-in unit Cooling. The Layout should consider the flow direction, shadowing effect, air preheating, re-circulation etc..

The Direction of Airflow should be as shown in image

REDI –Air Cool Mechanism – Important Rules to Remember

Rule 7-4: Thickness of Plu-in unit that interface with sub Rack’s Card Guide shall be 1.6mm +-0.2mm. But if Thicker PCB is recommended, then the distance from Primary side of PCB to Outside of Secondary cover is to be maintained as per Pitch of Plug-in units

Rule 7-5: Covers shall be electrically connected to safety ground with resistance not to exceed 100mohm

Rule 7-9: Maximum Plug-in Width is defined by following Table

Rule 7-11, 7-12: Primary & Secondary Side Cover is mandatory for TYPE1 and it is not required for TYPE2 implementations

Rule 13-1: In Order to achieve 2 Level maintenance, Type1 Plu-in units shall comply with ESD requirements of VITA 47

REDI –Conduction Cool Mechanism

REDI conduction Cool mechanism is defined by VITA 48.1

It defines the detailed mechanical implementation for conduction cool mechanism for PCB/Plug-In Units which is defined by VITA 46

In Conduction Cooled System, there are two important components namely Frame and Cover. Frame used to transfer the heat from PCB/components to Sub rack and Cover is used to cover the Both side of Plug-In units with support of ESD suppression

Cover Plate differentiates the TYPE1 & TYPE2 Cards

The PCB thickness can be variable from 0.06” [1.5mm] to 0.12”[3.048mm] and Even Thicker PCB also can be accommodated based on considering the Guide Rail Thickness and so PCB is limited on following

For Primary Side Retainer design – 0.137”[3.48mm]MAX

For secondary side Retainer Design – 0.112”[2.85mm]MAX

REDI –Conduction Cool Mechanism REDI conduction Cool mechanism defines 2 way implementation the Design based

on retainer placement. Primary Side Retainer

Secondary side Retainer

REDI –Conduction Cool Mechanism

REDI conduction Cool mechanism Supports Connector Side Protections as it is indicated by image

REDI –Conduction Cool Mechanism REDI conduction Cool mechanism – Primary Side Retainer

REDI –Conduction Cool Mechanism REDI conduction Cool mechanism – Secondary Side Retainer

REDI –Conduction Cool Mechanism REDI conduction Cool mechanism – Retainer Position

Plug-In Unit along with Retainer plugged on Guide Rail of Chassis with Gap of 13.34mm

In Retainer Relaxed State, thermal interface side should not have any gap with Rack Wall and Retainer side will have 0.76mm gap. Total Plug-in unit Thickness on Guide Rail is 12.57mm

In Retainer tightened state, Total Plug-in Unit Thickness will be 13.3mm

Card Guide Depth is 9.19mm to 10.41mm

REDI –Conduction Cool Mechanism – Guidance on Cooling

Component Layout can be critical to proper plug-in unit cooling. The layout should consider the how each component cooling, length and cross sectional area of heat transfer paths etc..

The conduction contact area for heat transfer from plug-in unit is dependant on several factors, including the depth of card, the presence of air cooled card guide projection.

REDI –Conduction Cool Mechanism – Important Rules to Remember

Rule 6-1: For Type1 Implementations, Both Primary & Secondary side covers shall be required

Rule 6-12: Covers shall be electrically connected to safety ground with resistance not to exceed 100mohm

Rule 6-11: Maximum Plug-in Width is defined by following Table

Rule 7-11, 7-12: Primary & Secondary Side Cover is mandatory for TYPE1 and it is not required for TYPE2 implementations

Rule 13-1: In Order to achieve 2 Level maintenance, Type1 Plu-in units shall comply with ESD requirements of VITA 47

REDI - VPX

Any Questions for Discussion..........

understanding the vpx redi

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