General

General

In CFX 2019R1, monitor plots are displaying power in the wrong units. A monitor plot that used to display values in [W] now displays in [kg m^2 s^-3 degree], and the values are different from those displayed in earlier versions like 19.1 Why is this happening and how can I revert back to the old behaviour?

    • FAQFAQ
      Participant

      In 2019R1 the convention is for the Solver Manager to convert the raw solver values to the user’s preferred units, as set under Edit > Options in CFX-Pre. The default unit system is the SI system, which has angles in degrees, so the Solver Manager will convert the solver’s raw values from [kg m^2 s^-3 radian] to [kg m^2 s^-3 degree]. The Solver Manager is now also displaying the units. The following workarounds exist. 1. set the expression for the monitor point to: myPowerOutput = myShaftTorque * speed2 * 1 [rad^-1] Without the extra angle unit in the final units string to confuse things, the Solver Manager does in fact manage to figure out that this should displayed as a power in [W]. 2. One workaround for getting the values correct is to set the unit options under Edit > Options to use “radian” as the angle units. This can be done by setting the unit system to Custom and then selecting radian for angle. This puts the values back to where they were in 19.1. The units label will still read “[kg m^2 s^-3 radian]” though, instead of [W]. This happens because there is currently no internal equivalenciy between [kg m^2 s^-3 radian] and [W], ie: Power has its ownunit system. 3. To completely revert back to the 19.1 behaviour, therefore,set the expert parameter “monitor units”= false before running the solver. Then the monitor data will be written without units and the SM will just display the raw data without unit labels as before.