# Custom Property of Data Types NULL value

**URL:** <https://forum.inductiveautomation.com/t/custom-property-of-data-types-null-value/33220>\
**Category:** General Discussion\
**Created:** [March 18, 2020, 5:53pm UTC](https://forum.inductiveautomation.com/t/custom-property-of-data-types-null-value/33220 "2020-03-18T17:53:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jespinmartin1](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jespinmartin1/32/57175_2.png) [@jespinmartin1](https://forum.inductiveautomation.com/u/jespinmartin1)\
**Post date:** [March 18, 2020, 5:53pm UTC](https://forum.inductiveautomation.com/t/custom-property-of-data-types-null-value/33220/1 "2020-03-18T17:53:40Z")

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I know I can use the default basic “Parameter” dataset to define a param for a Data Type Tag. But there is this Custom section where it’s supposed that you can create a custom property. I still don’t get it how to make it work because I’m always reading a null value.  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/f/f1b312d93e07ec72241887a1e46877db6cd9ff4a.png)  
First I can’t see it here

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/e/eb5cd1ec2e471eaf15c346d30b61e4086a72322b.png)  
but I tried  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/6/6728a8e8ebc3bda09626762b7c0eedf4586935ae.png)

When creating the instance  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/0/0fcba1e91c9fd399b7fcb8c964a117730d2dadbc.png)  
and  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/7/7e2042cf5cdd9fad742506bff9500be754f2b80b.png)

I know there’s a simple way to use it but I don’t know how. Any help?