FIX TD400 Serial driver-setting turbo frequency

[janezg-SLAC]

Description

Updating TD400 serial driver. Program waits until communication is established and then control parameter to set freq. gets updated with value from controller. After that program checks if user updated the control parameter to set freq and sends request to change frequency to controller.

Also updating conversion for Current and Power.

Motivation and Context

On PLC reboot program requested to change frequency on controller every time and set it always to minimum frequency.

How Has This Been Tested?

Function has been tested with DREAM PLC which has 4 of these TD400 controllers. Tried to reboot PLC, removed serial cable from pump controller and reconnect it back and program always update our control parameter with value from controller.

Where Has This Been Documented?

Pre-merge checklist

• Code works interactively
• Code contains descriptive comments
• Test suite passes locally
• Libraries are set to Always Newest version (Library, *)
• Committed with pre-commit or ran pre-commit run --all-files