Hello Richard, >From the extreme condition, ambient conditions need to be reached within 5 minutes. Think of this as a 5 minute or less ramp rate. If you have a really fast chamber, you can set it to do this in 5 minutes. Or optionally you can simply take the equipment out of the chamber which is at extreme conditions and place the product into ambient conditions. The product should be packaged during the test so condensation coming from a cold temperature should not be an issue. You can then leave the packaged equipment sitting around indefinitely until you decide you want to do the functional test. This could be immediately, 1 hour, 30 days, whatever. There are no time constraints on how long the equipment takes to start operating as some may have several minutes or more of firmware to load. The intent is to ensure that exposure to these extremes (when packaged) does not degrade the product compared to a product that has not been exposed. Of course many of us test unboxed as normally that is the last thing developed before the product is shipped. The risk is that the thermal shock on an unpackaged piece of equipment will be greater that way and could lead to "false" failures. But the testing is faster. In my experience I have never had a product fail these tests (and I have tested thousands) so I usually take the risk if I don't have boxes yet. My suspicion is that Bellcore, a long time ago, saw failures of disk drives and things like that which justified the testing.
Jim Jim Wiese NEBS Project Manager/Senior Compliance Engineer ADTRAN, INC. 901 Explorer Blvd. P.O. Box 140000 Huntsville, AL 35814-4000 256-963-8431 256-963-8250 fax [email protected] From: [email protected] mailto:[email protected]]On Behalf Of Georgerian, Richard Sent: Monday, March 28, 2005 10:29 AM To: IEEE emc-pstc Subject: GR-63: Low and Hi temperature exposure and thermal shock Greetings All, In the NEB Requirements: Physical Protection standard GR-63, sections 5.1.1.1 and 5.1.1.2, they both have the statement- "Perform post-test equipment's functionality test after the equipment has stabilized at ambient temperature." This is after the unit has been soaked in -40 degrees C or +70 degrees C for 72 hours in an environmental chamber. The unit is then removed from the chamber and into room ambient or the chamber ambient is increased to room ambient temperature in less than 5 minutes. In determining the units functionality, what is meant by the above statement? Is it to- 1) Turn the unit on immediately after removal from the chamber and observe what happens. 2) Turn the unit on immediately after removal from the chamber, wait until the unit has completed its power on sequence, then start to evaluate the unit's functionality. The power on sequence may take several minutes as components are warming up and may not start operating until they have reached a higher operating temperature.. 3) Wait until the unit's components has reached room ambient temperature, before powering on the unit. This may take more than several minutes before powering on the unit. As for pass or fail, if the unit does not function normally even when the unit has reached room ambient, it then fails. However, if it takes several minutes and goes through several resets, before finally functioning normally, is that a failure? Thanks to all in advance. Richard ===== Richard Georgerian Compliance Engineer Carrier Access Corporation 5395 Pearl Parkway Boulder, CO 80301 USA Tele: 303-218-5748 Fax: 303-218-5503 mailto:[email protected] ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
