Pot values

How do I determine the pot value to use.


The value to use depends on the speed of the PC you are going to use. The faster the machine is, the lower the resistance of the pot. On 8086 and 286 machines will 100 kohm pots work well. The easiest way to determine if your pot is suitable, is to use the TMWDCC program to test your potentiometer.
Plug in the pot between pin1 and pin3 of the game port. Start your machine and power up your processor card. Load the driver dcc-mbX.com, and run the tmwXXX.exe program. You should now have the throttle number 1 and 9 displayed on the screen.
Select the throttle command by typing a T and select to calibrate a throttle. Select to calibrate throttle number 1 and you will be prompted to put the throttle in max position. Observe the numbers displayed when you turn the knob. The number should never exceed 235. Chose a pot that will give you a max reading of around 220 - 230. The lower limit is not all that important, but do not exceed 235.
The value you have chosen for the pot is also the value to use as Xohm when you calculate the resistor values in a TypeB throttle.


© 1996 - 2006 Lars Lundgren