kamaroman68
Resolved by Rich!
I read Rich's tutorial regarding the l298 h bridge which is prompting this question. There was a spin off link that Rich directed me too that actually showed a bit of code to control a stepper motor. I need to set up something like that, and so what I would like to do is set D1 on and off rapidly creating an actual pulse. PWM will not work in this situation. Anyways my controller is looking for 5vdc to fire a optoisolator (led). I am powering my ezb4 via 12vdc. The output of the D0 ports is 12vdc Correct? What voltage would come out of the white wire, if any? My stepper controller is a bit different than the l2d8 requiring only a pulse on one input and a on/off voltage for direction. The controller can work on 12vdc but requires the addition of 820ohm resistors on these inputs. Thanks for the help.
It's very common to have two voltages feeding motor controllers. Most of them have this unless it has a on board voltage regulator.
Most logic is 3.3v or 5v, the absolute maximum voltages for logic on many ICs is around this range, I haven't seen anything that uses as much as 12v or 24v for logic. I am a little green in this area since I haven't had much experience with controllers etc. though.
To clarify my earlier statement regarding the dual voltages.... I do not like the fact that I will likely have to use a power robbing voltage regulator to drop my 12 volt sla battery down to 5vdc. These regulators in my experience waste power in the form of heat. Hopefully I will be able to add a relay circuit to turn on and off that regulator so it is not constantly draining. I have called tech support at parallax regarding the device. Awaiting a call back. Thanks again
So this question remains open unfortunately. After speaking with the tech at parallax it was stated that the above mentioned controller would only work with unipolar stepper motors. Dang it , I really thought we were on to something. Thanks Chris
I think I am going to try and run my current stepper motor controller with the ezb controller. I realize it will eat comms but it will be used very infrequently. If it does prove too much for ezb I will try the 555 timer method
Here is a URL to a site that has a possible solution to how to control a stepper motor using a micro-controller PWM signal:
http://www.tmart.com/Stepper-Motor-Driver-PWM-Controller-with-Pros-and-Cons-Speed-Governing-Multicolor_p250343.html?fixed_price=hk_intl&utm_source=base&utm_medium=organic&utm_term=88018789&utm_campaign=product&gclid=CKa0tIKjlr8CFZRj7AodMTEAYg
Thanks robot-doc I looked at that one also. If you use the magnifying glass and hover over the image you will notice that it too requires, a step pulse, an enable, and direction. Im starting to think something like this does not exist. Thanks for keeping an eye out for me! Chris
I really would advise against using scripts to produce the pulse. It's not just the comms which will become saturated (causing latency in all other controls) but the PC will become very bogged down and unresponsive also. It is certainly not a long term solution.