vba web scrapping - excel

Question

I have been able to launch the website and input the value but I'm not able to press enter to get the output value. It's an online calculator that allows you to see the temperature of a refrigerant while inputting a pressure. the output(temperature) is supposed to change when you input(pressure), however when I do it the output(temperature) stays the same while I'm able to change the input(pressure). could you tell me what might be the reason for this? is the website blocking my input? i get this error: (run-time erro91: object variable or with block variable not set)
when i run the code for this code "ht.getElementById("pressure").Value = "20""
enter image description here
here is my code:
Sub test()
Dim ie As InternetExplorer
Dim ht As HTMLDocument
Dim temp As Object
Dim press As Object
Set ie = New InternetExplorer
ie.Visible = True
ie.navigate ("https://reftools.danfoss.com/spa/tools/ref-slider#/")
Do Until ie.readyState = READYSTATE_COMPLETE
DoEvents
Loop
Set ht = ie.document
'input
ht.getElementById("pressure").Value = "20"
'Set temp = ht.getElementsByClassName("temperature")
'Set press = ht.getElementsByClassName("pressure")
'i = 1
'For Each te In temp
'Sheet1.Cells(i, 1).Value = te.innerText
'i = i + 1
'Next
End Sub

Answer 1

There is an API you can call to perform the same conversion. Below is an example implementation of calling that API using a custom function which accepts the pressure as input and returns the temperature in Celsius.
Option Explicit
Public Function GetTempFromPressure(ByVal pressure As Double) As Double
Dim body As String
body = "{""pressure"":""" & pressure & """,""refId"":""r404a"",""temperatureUnit"":""celsius"",""pressureUnit"":""bar"","
body = body & """pressureReferencePoint"":""absolute"","
body = body & """pressureCalculationPoint"":""dew"",""gaugeType"":""dry"",""altitudeInMeter"":0}"
With CreateObject("MSXML2.XMLHTTP")
.Open "POST", "https://reftools.danfoss.com/api/ref-slider/temperature?refId=r404a", False
.setRequestHeader "content-type", "application/json; charset=utf-8"
.send body
GetTempFromPressure = CDbl(.responseText)
End With
End Function
Public Sub test()
MsgBox GetTempFromPressure(20)
End Sub