PWM/HPWM Stepper Motor Controller

[DavyJones]

Normally I would design and build everything necessary to perform the tasks I need to with a PIC. In this case though to speed up development of my project I decided to use the stepper motor controller and relay module I am using to speed things up. The PIC is still doing all the work. I am working on a conveyer belt system that will move parts under a sprayer to get coated with a substance. I am controlling a solenoid to turn air on and off and a second solenoid to control dispensing the liquid, in this case for testing it is water. One thing I noticed since the nozzle is gravity fed and upside down as seen in my video, the gravity feed will produce a stream of water when the air is not engaged basically a constant drip so controlling the liquid flow (on and off) eliminates the drip. I did find no drip nozzles where I would only need to control the air flow but at $400 a pop that was not going to happen. The ones I am using are $20. My video is a mock up model for testing. I plan on adding a small conveyer pulley today and also control the stepper motor. If that succeeds I plan on moving to the next phase and build the working frame. I plan on using the extruded aluminum like many 3D printers use for frames.
If you or anyone else is interested in my progress as I move through this project I can keep posting the little videos I make.
Thanks for your help so far.
David
The air and liquid are not coming on simultaneously. The air valve is open first then 100ms seconds later I open the solenoid for the liquid. After 500ms of them both being on I turn them both off simultaneously then pause for 2 seconds to start the cycle again. This is producing almost virtually no drippage from the valve but I have on occasion seen a build up and a rogue drip is produced. I will mess with the timing to see if I can totally eliminate that or a tiny drip once in a while is not going to be bad since the part will have moved past the nozzle by that time.

[mark_s]

I am interested in following your project. It's nice to see a real application being developed.

Thanks for posting

[DavyJones]

I am interested in following your project. It's nice to see a real application being developed.

Thanks for posting

Sounds great I will keep posting to the thread as I go through my project... btw I am using a 12F683 since I had one laying around after my last project and I don't really need much for this. I'm setting up the stepper motor and about to give it a try in a few minutes.

David

[DavyJones]

Mark you obviously have experience with this controller (I hope) I am stuck with the connections to ena-, ena+, dir-, dir+ and pul-, pul+
I was assuming ena went to - and ena+ went to + dir - to - and dir+ to + and pul- to - and for pul+ I connected that to the pic to send the 1 and 0
I'm trying to find an example on the web haven't found one yet i am sure I am wrong as the stepper does not spin

[DavyJones]

Mark you obviously have experience with this controller (I hope) I am stuck with the connections to ena-, ena+, dir-, dir+ and pul-, pul+
I was assuming ena went to - and ena+ went to + dir - to - and dir+ to + and pul- to - and for pul+ I connected that to the pic to send the 1 and 0
I'm trying to find an example on the web haven't found one yet i am sure I am wrong as the stepper does not spin

Mark, Never mind I got it... the 12F683 did not like ROTOR=1 and ROTOR=0 I needed to high ROTOR and low ROTOR
it's spinning now going to try and make it smoother and faster mess around with those a bit

[DavyJones]

Mark, so I have been messing around with the time and seems to work pretty smooth. I am running 12v power supply and have the controller set to 1.5a and 1600 pulse per revolution. It is very smooth and easily see how to adjust the timing to speed it up or slow it down. One thing at these settings there is not much torque. I can grab the spindle and dont have to hold to tight to get it to not turn and growl at me. Motor says it is rated at 2.8amps but doesn't list the voltage but many people are saying 24v is optimum and can run up to 48 volts. If I up the current on the driver will that give me more torque or do I have to also up the voltage. At this configuration I doubt this will move my parts on the converyer once I have it built.
Thanks

[mark_s]

You are making a lot of progress. Increase the current setting, just monitor the motor for excessive heat while experimenting. 12 volts is on the low side for what you are doing. For small projects I have used old laptop wall supplies. They are usually around 18v at 3amps. You can find them in the thrift shops for cheap.