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Product : AT3600Serial Number : TC210/5228Firmware : 3.19Unit self test : pass selftestAccessories : AC interface connected on customer photos, however no tests use external source in test program, will check with Otis
Transformer / Inductor : UUT is Otis motor stator.
Spec attachedFixture Details : Connection photos attachedTests Used : Test program attachedRemote Operation : Customer used build automatic system, provided electrical diagram, which attachedQuestion : Otis found their AT3600 failed zero offset error when run test program early this year, power off and then power on, unit will works.
Unit shipped to Nantong for service on this February, found "Unit failed in selftest; ZERO offset error, code 0g6." See CN service report 11527.
Unit repaired by CPU swapped and returned.
Now
Otis reports same problem again.
AT3600 already at Nantong now, but it passed burn in test this time, see CN service report 11539.
Need some suggestions for AT3600 zero offset error when run test program.
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Dear Alvin,
I have had a look through all of the information and I cannot tell how the AT3600 is connected to the motor windings, and how the AC interface fixture fits in. There are no X tests (such as WATX, MAGX) in any of the test programs. This makes me a little concerned that the AT3600 is being damaged. If the external AC source is connected to the AT fixture across nodes that the AT3600 energises then it will damage the AT3600. An 0g6 error is very likely. This normally indicates either a damaged shunt switching relay (normally welded shut) or a power card relay that switches in the the power amplifier. Both of these could be damaged by a wrong connection. Sometimes these problems go away if the relay unsticks itself during transit.
If the system has been working for a long time before it failed then this may indicate that the test setup is OK and that an intermittent fault may exist on the AT3600 power card. The problem may have seemed to go away after fitting a new CPU card, but has returned as the real failing item was the power card. Do you have some more information about how the tests operate together with the AC source, AT3600, and motor?
Best regards,
Tim.
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Dear Tim,
That AT3600 passed burn in test at Nantong and has returned to cusomter, worked ok for one day. Now customer calling AT3600 fails again, show "Zero offset error" when run test program.
I already learned customer don't full understand how to use AT3600. Here are 3 evidences
1, They don't full understand must remove any fixture when run selftest ---- though they insist removed fixture when run selftest right now
2, They haven't use External AC source, but the AC interface fixture really connected, the leads connected from the AC interface fixture ( as photo shows) to 40 nodes fixture.
3, They use light curtain, but the relay used to short safety interlock, may not in right rate. Because before show" zero offset error" today, AT3600 happened "can't geneate voltage" when run high voltage test.
My question is: is that possible, customer's AT3600 really faulty but only in certain condition, which normal selftest can't cover?
I will ask customer remove the AC interface fixture connection since haven't on use, and carefully check the safety interlock cuicult circuit, especially the spec of relay.
Based on above information, do you have any more comments?
Thank you very much!
Best Regards
Alvin
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Dear Alvin,
Thanks for the extra information. The safety interlock connection can cause an 0g6 zero offset errors. If the relay has a bad connection then it will show 0g6 and "cannot generate voltage" messages. I would suggest that the customer tries another safety system just to prove what is causing the problem.
Best regards,
Tim.
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