You have to modify the "lowerBound" and / or "upperBound" attributes (see e.g. below) in the MSL declaration of the parameter or variable you are interested in. If you know in which file this MSL code fragment is, you can open that file through the Files tab of the Block Library Explorer window. If you don't know the file, you may want to try the Category Explorer window, or perform a search through Code/Find.
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OBJ Epsilon "Efficiency of the motor": Real := {: value <- 0.58 ; group <- "Power consumption"; interval <- {: lowerBound <- 0; upperBound <- 1; :}; :};