change interval to 30mins

[si458]

Description

Motivation and Context

How Has This Been Tested?

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

[HandyHat]

Closing this in favour of the solution suggested by Hildebrand here: https://forum.glowmarkt.com/index.php?p=/discussion/comment/544/#Comment_544

Thanks for the contribution @si458!