fixed-point in simvision

Delta_ V1 delta_ V2 delta_ V3 are all 20 bit signals, but in my Verilog code, they are processed as signed fixed-point numbers, with 1 sign bit, 4 integer bits, and 15 decimal bits. So he is actually a real number between -10 and+10, but simvision's radius can only be set to binary decimal, as shown in the above figure. I can only see its decimal value now. How can I set the form of its fixed-point number to facilitate my debugging? My simvision version is also in the picture