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Analog input for 0-10v vacuum gauge


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Looking for help getting my Samba SM70-J-TA22 to read my MKS 925 micropirani vacuum gauge on the 0-10VDC analog input. I have ML0 as my Analog IN and I'm reading values of 860 @ 1 volt and 1500 @ 9 volts. I need to linearize those values to 1E-5 and 1E3 respectively(chart below). Its a logarithmic scale so I'm not sure how to approach this. I know I need a MF as the pressure values have a decimal. Any guidance would be huge.

 

Chart.png.c5696680f17a6a50267b3daf120b2f51.png

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  • MVP 2023

You've probably already deduced that a regular linear block can't handle this.  

You're going to have to go into floating point land.  Convert ML 0 into a float an look at the functions available under Math->Float.  To see how to convert it, search "float" in the Help and choose Float:Convert.  Read the other Float topics while you're in there.

Here's a page I found that may have the formula you need:

http://stackoverflow.com/questions/19472747/convert-linear-scale-to-logarithmic

Google is your friend if you need more insight on the math.  It's been 30 years since I exercised the top buttons on my calculator.

Have a go at it and post what code you come up with if you need more help.

Joe T.

 

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