Metric conversion on Siemens HMI display

We have several Siemens basic panels in use on a production line. The line was bought from over seas and so all the display screens are using metric where any units of measurement are displayed.
All the units of measurement are metric in the PLC program, but there is a conversion button on the HMI's to convert all the displays to show imperial measurements.
One of the contractors said he did the conversion in the HMI program, and I didn't really ask how.
It's been almost 2 years of running now, and I have the need to understand how this was done. I've made some minor changes on the HMI's, but nothing like this.
I am using TIA portal v14.
Can someone help me understand how to do this within the HMI program?

I hope this request is clear. (Ex. - PSI --- kPa)

Thank you very much.

Part number of panel(s)?

If you can post a ZIP copy of the HMI program someone would be able to tell you exactly and where the conversions are done.

I did a google search 1 psi = x kpa

the answer I got was 1 psi = 6.89475729 kilopascals
my unit conversion handbook is at home, so this is all I have.
james

If it's a comfort panel, likely just using a scrip to scale or not scale the plc tag to an internal hmi tag for display based on a bit toggled by the metric/inch button.

you must have the source program.

Open the project in TIA
Select HMI / HMItags / Show all tags
Select the variable you want to convert
* In the "inspector window" select "Linear scaling"
you have a pair of values in the PLC and on the right the pair of values that you will see on HMI