On 9/23/2016 8:08 AM, Sag ich Dir nich wrote: > so you said i may need to add a pull-up resistor so i searched in the web and > read sometimes they use 10k, sometimes 15k, sometimes 5k and everything in > between (some say can be between 100 ohm and 100k ohm). How do i calculate > the > correct resistor value? Or is there a known working value for this?
It depends on things like the the drive capability of the output (which is very high in this case, since the FETs were designed to drive heaters and fans), the input impedance and capacitance of your motor controller and the wiring, and the time constants involved (ie: how fast or slow you need the signal to rise). Unless you have an unusual case, the specific value of resistor you use doesn't really matter a lot. For a 5V signal, I'd suggest something between 1K and 10K...just use what you have handy. If you have a range of values available or need to purchase something, I'd probably start with 3.3K or a nearby value (2.2K to 4.7K). Even better, if you provide details about the motor control you are using, I can review the specifications and perhaps recommend a real solution (the pull-up resistor is just a guess, but it shouldn't hurt anything to add). -- Charles Steinkuehler [email protected] -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
