# Momentary Button Question

**URL:** <https://forum.inductiveautomation.com/t/momentary-button-question/10002>\
**Category:** Ignition\
**Created:** [May 11, 2015, 10:34pm UTC](https://forum.inductiveautomation.com/t/momentary-button-question/10002 "2015-05-11T22:34:30Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![bellm](https://avatars.discourse-cdn.com/v4/letter/b/b5e925/32.png) [@bellm](https://forum.inductiveautomation.com/u/bellm)\
**Post date:** [May 11, 2015, 10:34pm UTC](https://forum.inductiveautomation.com/t/momentary-button-question/10002/1 "2015-05-11T22:34:30Z")

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Ok so I am new at all this and I am sure I am doing something wrong so that’s why I am asking yall.

So I created a momentary push button that when pressed will latch in an output in the PLC that controls lights. So I bound the Control Value to a PLC tag called hmi\_LightsOn. When I press and hold the button I can see the Control Value change to 1 and remain 1 until a let go of the button but the tag in the PLC never changes. If I change the tag to be bidirectional under the options of the button it works though. Any idea what I am doing wrong?

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**Author:** ![Paolo.Mariani](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paolo.mariani/32/3285_2.png) [@Paolo.Mariani](https://forum.inductiveautomation.com/u/Paolo.Mariani)\
**Post date:** [May 11, 2015, 11:42pm UTC](https://forum.inductiveautomation.com/t/momentary-button-question/10002/2 "2015-05-11T23:42:25Z")

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You are actually doing things exactly right. The buttons (and a lot of other components as well) do not automatically have the ability to write to tags. They only display the tag information. The Bidirectional setting allows a component like the button to be bidirectional, in that it can both read and write to a tag. So you did nothing wrong, and yes you do have to set the button to bidirectional to get it to write the value to the tag.