Configuring Analog Inputs to Your Asset

You have wired up your device, installed a SIM card, and created an asset for it within Telematics Guru, but what good is all that effort when the value you wanted to represent the fuel tank level is showing as 4,523 somethings? You need to find and set up the analog input from your device so that it makes sense for your application. This means conducting an analog value conversion.

Key Points

• Analog inputs simply records a voltage from the attached wire, we need to translate this into a meaningful value. i.e. tank level, temperature, pressure etc. for the users to derive a benefit from the data.
   
• The reading on the Orange/White wire is sent to the server in mV - i.e. 3000 = 3V
   
• We can convert the value by creating an I/O mapping. 

Example

1. Imagine we have a level sensor which outputs 1V when the tank is empty, and 5V when full.
    
2. By navigating to Assets, then Manage Assets, selecting our asset by clicking on its name to open the Edit Asset popup and then moving across to the I/O Mappings tab, Telematics Guru allows us to enter a conversion factor and an offset for our Analog input. 
   
   
    
3.  To find out what these values should be, we can create an equation of the form y = mx + c
   
   
   1. x = voltage in mV
       
   2. y = tank level in percentage
       
   3. i.e. the relationship between tank level from a given voltage.
       
4. With 1V representing 0%, and 5V representing 100% this gives us (1, 0), (5,100) in terms of x and y coordinates.
    
5. This handy calculator can help with the math - https://planetcalc.com/8110/ 
   
   
    
6. Take the slope and enter it as the conversion, and take the intercept and enter it as the offset.
   
   
    
7. Now, when the tank is empty, and the analog input reports 1000mV, our analog input 5 value will be 0%.
    

For more complex relationships - for example, where the analog value does not have a linear relationship with the required output, consider using Advanced Analog Mapping.