I have found a few related posts that have been very helpful, but I wanted to make my own post just to see if anyone can provide some more specific advice.
I am trying to modify a treadmill to act as a mono-directional Virtual Reality treadmill. I have a system set up to measure my displacement with a multi-turn potentiometer and just need some help using that to control the 180V 2.5HP DC motor in the treadmill.
I won't need to run this thing very fast, as anything other than a brisk walk is probably a bit to unsafe for VR (the user will be safely strapped into a harness system don't worry, that is necessary for safety and the measuring of displacement).
the basic function is, I need the treadmill to start moving in the appropriate direction as I move forwards or backwards, and stop and return me to the centre when I stop moving. I imagine once I have the basic system set up, I can adjust for speed and responsiveness in the code, but before I figure that out, I need to get the hardware working.
I have a KBMM-225 speed controller and the treadmill, I just don't feel I have a good grasp on how to set up the connection between the power supply, the speed controller, the motor and the arduino board. How I would wire it all up? What failsafes would you recommend? What do I need to be careful of when working with this high voltage stuff?
I could not find a schematic. The manual says the voltage-following input must be an isolated 0–9 VDC signal and warns not to earth-ground any input terminals. It also lists the SI-6 signal isolator as the option to use when an isolated signal is not available or when connecting to controllers/microprocessors.
So for practical purposes: the pot terminals, inhibit terminals, enable input, etc. should be treated as line-referenced/hot control circuitry unless you have the optional isolator installed.
For an Arduino or other logic controller, use isolation: relay contact, optocoupler, or KB’s SI-6/KBSI isolator depending on what you are trying to control. Don’t connect Arduino ground directly to any KBMM control terminal.
Ok so I'll need a signal isolator to get the Arduino talking to the speed controller as a voltage following connection.
Some other comments have however pointed out that it doesn't seem like I can reverse the direction of the treadmill with software, and that I would need to reverse the positive and negative leads every time I wanted to change direction. I will look into this, but anymore advice would be appreciated.
You can use a toggle switch or a relay to do the reversing but when you do be sure the motor is stopped first as it will act as a generator with reverse polarity.
Here is a wiring example:
