Disable "STEP" in Auto model

Hi， my English is not good, but I think that you means when robot is auto ,the step will turn off ? if it was , I think the system variables $SSR.$singlestep will be useful for you . you can write a BG -logic program , Associated UOP auto mode to change variables, you can try it.

Do you know how to control the indication of STEP mode also?

Simply altering the system variable you mentioned doesn't seem to change the status of "STEP"-indicator at the top-left corner of the TP screen.