Home Automation Switch Plate (HASP) - DIY touch controller

Ok

Do you have WLED working in openhab?
Did you use the binding here

What is the name of your WLED dimmer item?

In the interest of time I will assume you have these working.

Item

Dimmer WLedStringTestDimmer   "level"     {channel="wled:wled:Auto001:test:colour"}

Lets use the Slider on page 8 located at b9

When it changes it triggers the code in this section

else if (eventbutton == '9')
 {
 //Insert action to perform if dimmer 9 was moved
 }

We only want it to run if the value is not = to ON
So add

else if (eventbutton == '9')
{
    //Insert action to perform if dimmer 9 was moved

    if (HASP_Plate01_Plate_State_JSON_Value.state != 'ON') {               
        WLedStringTestDimmer.sendCommand(HASP_Plate01_Plate_State_JSON_Value.state.toString) 
    }
 }

Make sure you can control wled through sitemap first.

Make sure in the log you are getting command from HASP in the log file like

HASP_Plate01_Plate_State_JSON changed from {"event":"p[8].b[9]", "value":"ON"} to {"event":"p[8].b[9].val", "value":21}