Expression Structure in Vision

Ignition
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1

Hello all, I am rather new to using vision as I have mainly used perspective up to this point. However, I am working on vision now and I have ran into an issue.

I have a display whose data is determined by taking two integers, converting them to 8 bit binary numbers, combining the binary numbers to create a 16 bit binary number, then converting that 16 bit binary number to a double value. It is the finale double value which is displayed.

I have done this in perspective by binding the value to an expression structure and then transforming the data using the following script:

num1 = value["key"]
num2 = value["key_1"]
binary1 = format((num1 & 0xFF), '08b')
binary2 = format((num2 & 0xFF), '08b')
Combined = binary2 + binary1
mBar = int(Combined, 2)
PSI = mBar/68.948
return PSI

Where key is the first tag and key_1 is the second tag.

This works as expected and the correct value is displayed. However, I need to display this exact value in a vision project now. But when I went to go through the same process on the display in vision, I noticed that vision does not have an expression structure option for binding and only an expression option.

Given this, what would be the best course of action to take. I am not sure how I can fit my script all down into the single expression that is required using just the expression option. Is there a way to get in vision a similar binding to the expression structure and transform option that is in perspective?

Thank you in advanced to any help.

2

Vision has neither transforms nor structure bindings. Typically, since a script is involved, one would use runScript() in an expression binding to call a project library script function, passing your arguments to it. (Also typically with a zero poll rate, so it runs only when the arguments change.)

3

Where are the two integers coming from? Are they tag values?
If they are then just create an expression tag,
({[.]numHiByte} * 256 + {[.]numLoByte}) / 68.948)

This should do the job if you are sure that the two bytes won't go negative.

4

That makes sense thank you I will do my scripting this way.

5

Yes they are tags but it can be a negative value so I am going to do as @pturmel said and use the project library script