Scaling Tab

 All analog I/O tags include a Scaling tab on their tag properties folder.

Sensors and other hardware typically work with a range of discrete values that are much more finely divided than standard engineering units such as degrees.  For example, a temperature sensor might report values within a working range of 0 to 4095.  Depending on the sensor’s calibration, the low end of the scale, 0, might represent 32deg.  At the high end of the scale, 4095 might represent 200deg.  Given these points, and assuming a linear relationship, one can then calculate the actual temperature indicated by any value output from the sensor.

Working the other way, one can also calculate the equipment value required when an output tag is used as setpoint.

The Engineering Units property of the I/O tab is used to identify the unit value associated with the scaled value.