SysAdmin/Calculated-Fields.md

@@ -81,7 +81,7 @@ Each one of these functions can create a Calculated Field based by applying a ma
 
 In this example, there already is a sensor that reports the firing rate of a boiler as a percentage value varying from 0 to 100.  We now want to create a Calculated Field that displays the rate of natural gas use of the boiler, expressed in Btu/hour.  Because the gas use and the firing rate of the boiler are linearly related, we can use the `linear` Calculated Field function to create this gas usage field.  Multiplying the firing rate by 1500 will give the gas usage in Btu/hour since the maximum gas usage of the boiler is 150,000 Btu/hour; a 100 firing rate times 1500 gives a gas usage of 150,000.
 
-The `linear` function has three variables: `val`, `slope`, and `offset`.  For our example, our conversion multiplier of 1500 is the `slope` variable, and you can see its entry in the `Function Parameters` in the above screenshot.  The `offset` variable is not needed in this application; BMON has a default value of 0.0 for this variable, which is correct for our application, so therefore we need not provide the variable in the `Funcation Parameters` box.  Finally, the `val` variable will be used for the Firing Rate sensor values that we are using to calculate gas usage.  Since this variable needs to be filled in with sensor values, *we need to preface the variable with `id_`* to indicate that this variable is a set of sensor values.  Then, the value provided for the variable in the `Function Parameters` box is a Sensor ID:
+The `linear` function has three variables: `val`, `slope`, and `offset`.  For our example, our conversion multiplier of 1500 is the `slope` variable, and you can see its entry in the `Function Parameters` in the above screenshot.  The `offset` variable is not needed in this application; BMON has a default value of 0.0 for this variable, which is correct for our application, so therefore we need not provide the variable in the `Function Parameters` box.  Finally, the `val` variable will be used for the Firing Rate sensor values that we are using to calculate gas usage.  Since this variable needs to be filled in with sensor values, *we need to preface the variable with `id_`* to indicate that this variable is a set of sensor values.  Then, the value provided for the variable in the `Function Parameters` box is a Sensor ID:
 
     id_val: Burt158_firing_rate