On 11/06/2011 10:37 AM, Viesturs Lācis wrote: > 2011/11/6 Slavko Kocjancic<[email protected]>: >> >> I agree that filtering is good thing to do. But in this case (running >> near 1 hour without problem) the EMI isnt the source of trouble. > > Thanks, guys, for suggestions! > I will try to figure out, how to test, if PC is ok and if the > spindles/VFD does mess the thing for the starting point, because I > also think that the tendency for machine to work correctly some time > after turning it makes the whole situation frustrating. > > Viesturs
Just reading this thread takes longer than troubleshooting should take. Lots of good suggestions, with a number of repeats, but there's one thing that I don't remember reading: cost of troubleshooting. It's one thing to troubleshoot a hobby machine, it's another to do it on a production system. I cannot imagine running test programs on production PC for hours to troubleshoot memory or anything else for that matter. Correct me if I'm wrong, but production loss in time, ruined parts, and delivery in one day is likely (times) more than the cost of whole PC and possibly other electronic components comprising the CNC system. Question: why is it that the end user does not have spare kit(s) (whole PC or a motherboard, memory, disk drive, sensors, etc.) on site? And if not, why is the supplier not providing spares to replace them during first troubleshooting session? Spares are cheap compared to production loss especially when travel is involved! When you have intermittent problems that cannot be found in an hour by troubleshooting means suggested in this thread, it's time to start changing parts depending on their (statistical or experienced) possibility of failure, ease of access to the components, or complexity of changing them. That way you take care of two problems: bad component or subassembly, and intermittent connections between those components. You have to be careful not to introduce new problems of course. It might turn out that the replaced component was not bad at all and it could be used as a spare or for troubleshooting purposes next time. I used to test field replaced boards back in office on test computers. Good boards were labeled and returned to our stock. That 80's practice should work today too. One possibility would be to connect a second computer without removing the original assuming cabling could be taken care of. And it should if designed properly. Also, a number of messages addressed interference and noise issues. What hasn't been mentioned is how to measure this. My suggestion would be to bring an oscilloscope (I depend on my old Tektronix 2445 and little Velleman Personal Scope) on-site to see the quality of electric signals on sensor and power lines, power supplies, and PCB boards. You can easily buy cheap digital scopes with sufficient capabilities for field service these days. Good DMM also needs to be part of tech or engineers tool box. As the saying goes: show me your tool box and I'll tell you how good an engineer or technician you are. Scope will tell you if you really need a line filter or not. Just throwing new components into the system is likely a waste of time and $ and might introduce new problems as well. Anxious to read the rest of the story, -- Rafael ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
