If you experience the following error message during Ball Plotting, It is because the m+g value for the file you are plotting is set to zero and CALSoft cannot calculate a cook time (Bb) using the Ball Formula...
CALSoft Error: Conversion from string "" to type 'Double' is not valid.
Location = Exception caught globally
- ** NOTE that the m+g is a factor used in the Ball Formula to represent the hypothetical difference between cooling water and retort temperature at the start of cooling. Typiclally, the m+g is set to 180°F (100°C) for Steam Retorts or 130°F (72.22°C) for Water Retorts
This is typically encountered when you are plotting a file that was imported from an Ellab or Datatrace file. When you import data from an Ellab or Datatrace file, CALSoft creates a CALSoft .chp file. The import will only bring in the Time/Temperature data, but CALSoft allows for more information about the test to be entered in the Product Info, Test Targets, and Test Info section. This information is typically not required. However, this is an issue if you do not enter anything for the “Retort Type”. Choosing the Retort Type from the dropdown menu will auto-set the "m+g value", which is a factor required for the Ball Formula to calculate a cook time. If you do not choose a retort type, the default m+g value will be set to 0.00 when you plot the data. The CALSoft file information will look like this after you import data from Ellab or Datatrace (notice that the Retort Type is not chosen)....
When you plot a file in CALSoft, the software will calculate and display the cook time (Bb) as you plot. CALSoft uses the heating factors in real-time as you plot, along with the RT, IT, Fo, and m+g (all factors Ball needs to calculate the cook time). If the Retort Type was not chosen during the Ellab/Datatrace file import, the m+g will be “0.00”, and Ball Formula cannot calculate a cook time. This will cause CALSoft to encounter the error....
To fix this, simply choose the retort type from the dropdown list in the main part of the heat penetration file and save the file. Then when you plot the data in the file, the correct m+g will be set, and you should then be able to plot without any issues.