# AB SLC 504 Major Error Halt Bit

**URL:** <https://forum.inductiveautomation.com/t/ab-slc-504-major-error-halt-bit/6213>\
**Category:** Ignition\
**Created:** [April 12, 2013, 2:38pm UTC](https://forum.inductiveautomation.com/t/ab-slc-504-major-error-halt-bit/6213 "2013-04-12T14:38:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Henry](https://avatars.discourse-cdn.com/v4/letter/h/df705f/32.png) [@Henry](https://forum.inductiveautomation.com/u/Henry)\
**Post date:** [April 12, 2013, 2:38pm UTC](https://forum.inductiveautomation.com/t/ab-slc-504-major-error-halt-bit/6213/1 "2013-04-12T14:38:00Z")

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I’m using the AB UA server and trying to read the Major Error Halt bit S:1/13. The tag reports a not connected data quality but all other tags from the PLC are good. Also, the location doesn’t appear in the quick client. However the location is legitimate and can be read properly using an old Kepware DA server.

Thanks for the help

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**Author:** ![thechtman](https://avatars.discourse-cdn.com/v4/letter/t/e56c9b/32.png) [@thechtman](https://forum.inductiveautomation.com/u/thechtman)\
**Post date:** [April 12, 2013, 4:11pm UTC](https://forum.inductiveautomation.com/t/ab-slc-504-major-error-halt-bit/6213/2 "2013-04-12T16:11:18Z")

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Try S2:1/13

All status is in data file 2 in the SLC, MicroLogix and PLC-5 processors. Even though some drivers may allow dropping the 2, the Ignition A-B driver requires it.

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**Author:** ![Henry](https://avatars.discourse-cdn.com/v4/letter/h/df705f/32.png) [@Henry](https://forum.inductiveautomation.com/u/Henry)\
**Post date:** [April 12, 2013, 10:15pm UTC](https://forum.inductiveautomation.com/t/ab-slc-504-major-error-halt-bit/6213/3 "2013-04-12T22:15:41Z")

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Thanks for the help