This is an extremely remedial question, I am sure, but I am new to this world. I have a Tic 36v4 and i am wanting to have both USB control as well as a manual control. Simplest terms, I want to have 2 buttons (up/down) and a potentiometer for speed control as manual inputs when I can’t control the Tic via USB. I see a lot of answers about how to wire a potentiometer, but I can’t seem to find anything that lays out in relatively clear/simple terms how to do this, if it is even possible. Everything I can find, after a lot of google-fu, still doesn’t seem to answer my question. Is there a forum post, or an article, that lays this out in simpler terms? Any help or direction would be greatly appreciated. Thanks!
Hello.
The Tic does not have direct support for the control method you described with the buttons and potentiometer. However, when in analog speed control mode, the Tic will map the input voltage to the motor speed, with values under the configured neutral point turning the motor in the negative direction and values greater than the neutral point turning the motor in the positive direction. So, if you want to control the direction with pushbuttons and the speed with a potentiometer, you could use analog speed control mode with some additional circuitry like this:
With this configuration pressing both buttons at the same time would create a short between 5V and GND, so you might consider using a switch instead of the buttons to prevent that situation.
Additionally, please note that you will need to re-configure the control mode to “Serial/I2C/USB” when you want to control it via USB.
Brandon
So the analog mode may work for me. Would that be a PWM dial or does it need to be a stepper controller? I would presume a PWM given the explanation as I understand it. I assume you can select where the voltage would be for the “neutral” position and it doesn’t have to be split 50/50? I would need more control for one direction than the other, so I would want to do something 30/70 instead. Last question, how do you determine where neutral is to stop the motor? This controls the tower on a fiber laser and I can’t have it moving and changing focus mid burn. Thanks for all your help already. I really appreciate any further info you could share.
Hello.
I am not sure what your referring to with this question. If you’re asking about the potentiometer, it can just be a simple rotary potentiometer like this. Then, as shown in the diagram, you would connect the wiper (i.e. the middle pin) to the Tic’s SDA/AN pin, and you can use the Tics 5V and GND pins as the source for 5V and ground. So, the voltage delivered to the SDA/AN pin is a pure analog voltage (not PWM). Please let me know if I have misunderstood your question.
You can adjust the neutral position as well as the mapping of the min and max values to the target speeds using the analog scaling options in the “Input and motor settings” tab of the Tic Control Center. You can find more details in the “Setting up analog speed control” section of the Tic user’s guide. As described there, you can adjust the neutral min and neutral max values, effectively configuring a dead-zone where the Tic will keep the stepper motor stationary.
Brandon