Diff 16

I'm surprised that no-one has spotted that there was an error in the image posted of the front end of the program. The image I posted as Diff 09 is incorrect and does not match the description given. This is the correct front end for the program.

 

Just to confirm:

 

These blocks control the front end which affect the behaviour of the buttons and dials and sets variable "a" which is the train speed.

 

The three blocks on the left are the controls for the buttons. The train speed is increased and decreased in steps of 10 out of 200. The wait block sets the minimum time between button presses, which I have set to 0.1 seconds.

 

The other two blocks on the top line set the maximum and minimum train speed as 200 and -200, so that no matter how many times the buttons are pressed these limits are not exceeded.

 

The remaining three blocks are for the dials. Because the range of "a" is 200 to -200, this variable is divided by 2 as the dial generally shows a range of 100 to -100, so this ensures that the reading is compatible.

Done