Slider bar default value after device re-start

I have a modbus device (VFD) and two of the parameters to control it are “Freq” and “Ramp” which I have bound to tags via slider input components. From the controller side, I only read from those modbus holding registers, I never write to them from the device.

If everything is running and I restart the device, the slider bar values automatically change from whatever value they were set at to ‘0’. What is causing this and how can I either maintain the slider value on re-start or have a default start value other than ‘0’?