Hi, I’ve made some modifications to a steering wheel and pedal set by replacing the 10K pots with 100K pots. This was done according to the Operator Interface reference guide. On page 5, they show a wiring diagram for a typical 100K potentiometer. The way I’ve used pots in the past are as variable voltage dividers. By taking a look at the wiring diagram, the third pin is labeled to have no connection. If this is true, then the pot would act as a variable resistor instead of as a voltage divider. I was wondering if this is a typo, or if I should disconnect the ground lines of the pots in the steering wheel and pedal set.
Apparently the OI is designed to have the pot wired exactly as shown in the diagram…with only one end connected. This is a safety feature that will allow the OI to detect when the joystick cable is pulled out, and shut off the robot drive.
I’ve been advised by a couple knowledgeable people here to wire it as shown in the diagram when I asked the same question.
Thank you very much, squirrel! I was told that the joysticks that came with the KoPs are wired like voltage dividers? Is this a problem? Would voltage dividers work fine?
IFI completes the voltage divider internaly to the OI. This allows them to determine if the analog port is used.
Voltage dividers will work, but not perfectly. You need to put a series resistance in the ground side to offset the voltage so the OI can read the full range of values from the potentiometer. I think the lower limit of usable voltage into the OI is about 600 millivolts.
I apologize for not being more specific, but I never actually did this. I’m just remembering a discussion from some time last year.