Forum: Reliability & Maintainability Questions and Answers
Posted by: Mark Schofield (email@example.com )
Date posted: Thu Feb 21 11:34:50 US/Eastern 2002
Subject: STANAG Interface for RMM
Does anyone have an experience on the in-service reliability of the STANAG 4575 interface for Removeable Memory Modules in terms of how often the RMM can be inserted/removed before replacement of the connector is necessary? We shall be using the MIL_DTL-24308E D-type connectors with our implementation. The standard requires a minimum durability of 500 make/break cycles for this connector. In the absence of supporting data this effectively lifes the interface at 500 times the average removal interval which is an unattractive proposition in terms of total ownership costs. Comparision wuith commercialy available non-STANAG interfaces for similar applications reveals claimed life-times of up to 25000 cycles. The truth probably lies somewhere in the middle - but where?
Posted by: Richard Smith (firstname.lastname@example.org )
Date posted: Tue Feb 19 8:54:28 US/Eastern 2002
Subject: Specification for PCB Insertion Cycles
Just wondering if anybody knows of a specification (mil-spec or otherwise) that defines how many times a PCB should be able to be inserted onto a card edge connector before the laminate deteriorates or the contacts start to peel. For example, a computer video card being inserted and removed from a PC motherboard. I would appreciate any info that anybody has.
Thanks in advance.
Posted by: Paul Hare (email@example.com )
Date posted: Fri Feb 15 11:57:44 US/Eastern 2002
Subject: FRAM and Reliability
I am thinking about using a Ferroelectric Nonvolatile RAM component (FRAM), but I'm not familiar with the reliability of the technology. Does anyone out there have positive or negative comments that they could give me?
The data sheet for the part in question states "A ferroelectric random access memory or FRAM is nonvolatile but operates in other respects as a RAM. It provides reliable data retention for 10 years while eliminating the complexities, overhead, and system level reliability problems caused by EEPROM and other nonvolatile memories." I guess on a system level, it may be more reliable; but as a component, how does it stack up against more standard RAM technologies... Thanks in advance for comments, Paul Hare e: firstname.lastname@example.org Compliance Engineer w: 978.206.9179 Pirus Networks f: 978.206.9199 43 Nagog Park c: 508.450.0376 Acton, MA 01720 i: www.pirus.com
Posted by: Dick Creamer (email@example.com )
Organization:NAVAIR Depot Jacksonville, FL
Date posted: Mon Feb 11 15:29:10 US/Eastern 2002
I'm trying to calculate the Ao for a fielded avionics system which may not be turned on for every mission. There is no elapsed time meter on the system. I understand total uptime would include operating time plus standby time. The conflict I'm involved in is what constitutes standby time? Is it the total flight hours in which the system is not turned on? Or, is it the rest of the year that the system is not operating? Or, does the concept of standby time even apply? It stands to reason that the system is not going to be available if you don't turn it on. Help!
Posted by: Richard Smith
Date posted: Mon Feb 11 14:58:17 US/Eastern 2002
Subject: Safety Hazard Checklist
Does anybody know of a source for a comprehensive checklist of possible hazards etc. that could be reviewed when undertaking a safety/hazard analysis ? The product that will eventually be under review is for the aerospace industry, but I would appreciate pointers from any other industry also.
Any help appreciated. Thanks.