Xiaofan Chen wrote: >On Wed, Jun 18, 2008 at 11:41 PM, William Bross wrote: > > >> My big concern is that I have never had any >>requirements to hipot test any low voltage equipment - EVER. >> >> > >This is certainly not true. I have run hi-pot tests for all kinds of >low voltage device. This depends on the specification of the >device. For example, for PLC I/Os, we need to have isolation >between the backplane and field side, so we need to do >HiPot tests between them even their power supply is normally >24V (10-30V). And if you have uninsulated >connectors exposed, you may have to do hi-pot tests as well. > > > Xiaofan, Yes, this equipment did get hipot tested in their lab and passed with flying colors. BTW this device is very similar to a PLC in function and form only more job specific, so it did get all those tests. My big concern is wasting production resources to test every blippin' unit off the line. >>I've done >>many mains power driven devices and they usually get a hipot test. >>Common sense engineering would lead me to believe that hipot testing low >>voltage DC instruments with these levels for 2 seconds would surely >>damage parts of the instrument, like the 36V TVS diodes across the power >>inputs. >> >> > >Do you have different circuits in your device which need isolation? >What is lab say about the HiPot test? > >You know you can have hi-pot tests between different section of the >circuits. You may not need to do Hi-pot tests between the DC voltage >(say 24V and return). > >Xiaofan > > Yes, there are multiple isolated sections and each was tested individually with the standard hipot tests. With up to 70 individually isolated I/O points, a testing jig might not be economically feasible and the probability of production messing up any one connection could render a section of hardware inoperable. My point to them is they proved the design passes the tests so why all of a sudden is production line testing mandatory? We've petitioned and we're waiting for a decision. Thanks, Bill -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist