# Ignition V7.0.5 (b4679) quality attribute is write only?

**URL:** <https://forum.inductiveautomation.com/t/ignition-v7-0-5-b4679-quality-attribute-is-write-only/1649>\
**Category:** Ignition\
**Created:** [March 17, 2010, 3:24am UTC](https://forum.inductiveautomation.com/t/ignition-v7-0-5-b4679-quality-attribute-is-write-only/1649 "2010-03-17T03:24:14Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![ISDProj](https://avatars.discourse-cdn.com/v4/letter/i/58956e/32.png) [@ISDProj](https://forum.inductiveautomation.com/u/ISDProj)\
**Post date:** [March 17, 2010, 3:24am UTC](https://forum.inductiveautomation.com/t/ignition-v7-0-5-b4679-quality-attribute-is-write-only/1649/1 "2010-03-17T03:24:14Z")

</div>

I have been trying to use the system.opc.readValue() function  
I have successfully read a tag but when I try to reference the “quality” attribute I get

[code]AttributeError: write-only attr: quality

```
at org.python.core.Py.AttributeError(Py.java)
at org.python.core.PyBeanProperty._doget(PyBeanProperty.java)
at org.python.core.PyObject._doget(PyObject.java)
at org.python.core.PyInstance. __findattr__ (PyInstance.java)
at org.python.core.PyInstance. __findattr__ (PyInstance.java)
at org.python.core.PyObject. __getattr__ (PyObject.java)
at org.python.pycode._pyx275.f$0(<TagChangeScript:ForceOnTop>:4)
at org.python.pycode._pyx275.call_function(<TagChangeScript:ForceOnTop>)
at org.python.core.PyTableCode.call(PyTableCode.java)
at org.python.core.PyCode.call(PyCode.java)
at org.python.core.Py.runCode(Py.java)
at com.inductiveautomation.ignition.common.script.ScriptManager.runCode(ScriptManager.java:367)
at com.inductiveautomation.ignition.common.script.TagChangeScriptManager$TagChangeScriptHandler.tagChanged(TagChangeScriptManager.java:118)
at com.inductiveautomation.ignition.client.sqltags.impl.ChangeNotifier.run(ChangeNotifier.java:37)
at com.inductiveautomation.ignition.client.sqltags.impl.db.DatasourceTagManager$BatchNotifier.run(DatasourceTagManager.java:765)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

```

[/code]

This is my “test” code

```auto
qv = system.opc.readValue("IgnitionOPCUA","[ControlLogixPLC]Global.Tag_To_Be_Read")
#these work
print qv.value
print qv.timestamp
#these cause the error
print qv.quality
print qv.quality.isGood()
```

Is there something I’m missing?

---

<div class="post-metadata">

**Author:** ![Carl.Gould](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/carl.gould/32/7262_2.png) [@Carl.Gould](https://forum.inductiveautomation.com/u/Carl.Gould)\
**Post date:** [March 17, 2010, 4:25pm UTC](https://forum.inductiveautomation.com/t/ignition-v7-0-5-b4679-quality-attribute-is-write-only/1649/2 "2010-03-17T16:25:36Z")

</div>

This is due to a subtle quirk in how Python is looking at that attribute. Try “qv.getQuality()” instead.

---

<div class="post-metadata">

**Author:** ![ISDProj](https://avatars.discourse-cdn.com/v4/letter/i/58956e/32.png) [@ISDProj](https://forum.inductiveautomation.com/u/ISDProj)\
**Post date:** [March 18, 2010, 2:09am UTC](https://forum.inductiveautomation.com/t/ignition-v7-0-5-b4679-quality-attribute-is-write-only/1649/3 "2010-03-18T02:09:28Z")

</div>

Thanks Carl, This works 🙂  
The manual doesn’t mention anything about getQuality() - it may need to be added 😉

Peter