Software Support > Automated Projects
DNA Dan's discussion about secret drive
DaOld Man:
Think about it.
When the PWM drive is turned on, it switches the motor on by connecting the ground to it. (Ground is switched by TR1 on the PWM)
But by using it with the secret drive, when the PWM is on, the enabled to the secret drive is off.
Secret enable is off because PWM is turning on the ground on its out contacts.
When PWM is turned off, the enable on the secret is turned on because it is connected to + through the resistor.
It is working opposite the way the motor would work, if the motor was hooked up to the PWM.
It is inverting the PWM pulse wave.
But it shouldnt make any difference, just your speed control might be reversed. Im not even sure it would be reversed, but it sure looks like it would be. If this is a problem for you, you can add a PNP transistor to invert the signal back.
- Out on PWM would turn on the PNP transistor which would connect the secret enable to +.
Or you can leave out the TR1 on the PWM and connect the drive enable directly to the R4 resistor, where the base of TR1 would connect.
At this point here, the signal would be ON (+) or Off (ground). So no bias resistor (to +) would be necessary.
This would correct the signal to the drive enable.
Check out the attached drawing.
EDit: added another drawing which shows the real board component locations.
DNA Dan:
Wow. You're a rocket scientist! How do you see these circuits in your head so easily? I mean I really need to think about them to know what's going on. I ordered the PWM kit and some other things. I just need to go to a local Radio Shack and get some wire/connectors. What gauge wire should I use for this?
I modified the drawing a bit to keep it clear in my head. I color-coded the wires to match the secret motor drive. I also made the SPDT switch On-On two-way toggle for my control panel, this introduced the SPST main switch back in the picture.
So if this works, all I would need to do to convert this to a printer port is move D1/D2 and the grounds on the limit switches. Correct?
I know yellow isn't the best color to use for this, but I need to keep this straight!
DaOld Man:
If I was a rocket scientist we would still be trying to get a monkey in space ;D
Your circuit looks good. Remember you may need to add two 1 K resistors to D1 and D2 to ground. Not sure if the inputs on the secret drive will "float" or not. They may need to be pulled to ground to keep them from false triggering.
Just keep this in mind if you have any problems with it.
Good luck, and keep us informed!
BTW, you asked about connecting the secret drive to the printer port.
Check out this drawing. Quite a bit simpler, isnt it?
DNA Dan:
::) Yea.. I don't know, maybe it's just a control thing! I would still need to get a printer port card thingy, or scrounge an old computer. I assume speed is controlled through MRotate3 as well?
DaOld Man:
--- Quote from: DNA Dan on March 12, 2011, 11:59:28 pm --- ::) Yea.. I don't know, maybe it's just a control thing! I would still need to get a printer port card thingy, or scrounge an old computer. I assume speed is controlled through MRotate3 as well?
--- End quote ---
Yes, MRotate can pulse forward, reverse, and enable for speed control. But of course you could still use the PWM drive like you currently have planned with MRotate.
I am looking forward to seeing your project come to life. Your idea can be a good option for people who want to use manual operation for their rotating rigs.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version