Re: [Emc-users] hal servo questions

Chris Radek <[EMAIL PROTECTED]> wrote: > On Mon, Oct 08, 2007 at 07:51:59PM -0600, Sebastian Kuzminsky wrote: > > Duty cycles from 0 to about 55% give me increasing whining from the > > motor but no movement at all. 55 to 100% gives increasing motor speed > > and torque. > > I think my linearity

Re: [Emc-users] hal servo questions

"Jim Coleman" <[EMAIL PROTECTED]> wrote: > On 10/11/07, Sebastian Kuzminsky <[EMAIL PROTECTED]> wrote: > > Are you suggesting a fat ground wire from the ground on the driver > > circuit to the case of the PC? > > pretty much, in case there is some wicked ground loop, or an accident, you'd > have a

Re: [Emc-users] hal servo questions

On 10/11/07, Sebastian Kuzminsky <[EMAIL PROTECTED]> wrote: > > "Jim Coleman" <[EMAIL PROTECTED]> wrote: > > im pretty sure the 7805 5V regulator would work for ya, to provide a 5V > > logic supply from the 24V supply, they should only be a dollar or 2 at > > radioshack. then you could eliminate t

Re: [Emc-users] hal servo questions

"Jim Coleman" <[EMAIL PROTECTED]> wrote: > im pretty sure the 7805 5V regulator would work for ya, to provide a 5V > logic supply from the 24V supply, they should only be a dollar or 2 at > radioshack. then you could eliminate the atx supply. Heh, I just discovered the LM7805, and yeah it looks l

Re: [Emc-users] hal servo questions

im pretty sure the 7805 5V regulator would work for ya, to provide a 5V logic supply from the 24V supply, they should only be a dollar or 2 at radioshack. then you could eliminate the atx supply. I would also stick in a wire to ground to the chassis of the pc. i'd be afraid of the port sinking a

Re: [Emc-users] hal servo questions

Chris Radek <[EMAIL PROTECTED]> wrote: > I think my linearity is much better than you describe. Maybe try > pure pwm mode (not pdm)? Or it may just be a matter of your low > power supply. I'm using 24V on mine. I picked up a new power supply (24 VDC, 3.6 A), but I couldnt get my setup to work w

Re: [Emc-users] hal servo questions

brushes and bearings. They seem like pretty decent servos although full of carbon ;) sam - Original Message - From: "Kirk Wallace" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" Sent: Wednesday, October 10, 2007 4:42 AM Subject: Re: [Emc-users]

Re: [Emc-users] hal servo questions

On Tue, 2007-10-09 at 14:50 -0500, [EMAIL PROTECTED] wrote: ... snip > nonlinear issues. I started out using pdm from the printer > port but broke down and bought a pluto and mesa card. > > here are the eagle files > http://www.electronicsam.com/images/KandT/servostart/schem/ > ... snip In brow

Re: [Emc-users] hal servo questions

Sebastian Kuzminsky wrote: > Sebastian Kuzminsky <[EMAIL PROTECTED]> wrote: > >>Jon Elson <[EMAIL PROTECTED]> wrote: >> >>>You need a lot more voltage supplying the H bridge. At 55% duty >>>cycle, you are getting 12 * 0.55 = 6.6 V at the motor. I am a >>>little surprised the motor doesn't star

Re: [Emc-users] hal servo questions

Sebastian Kuzminsky wrote: > Jon Elson <[EMAIL PROTECTED]> wrote: > >>You need a lot more voltage supplying the H bridge. At 55% duty >>cycle, you are getting 12 * 0.55 = 6.6 V at the motor. I am a >>little surprised the motor doesn't start to turn before this, it >>must have a lot of frictio

Re: [Emc-users] hal servo questions

gecko servo drives are step and direction input. this puts the pid loop outside of emc. (for some reason I don't like that ;)) I have been playing around with a 10+ amp fet bridge that jmk helped me with. It has no current limiting but has not been a problem so far.. It does turn on the lower 2

Re: [Emc-users] hal servo questions

Chris Radek <[EMAIL PROTECTED]> wrote: > On Mon, Oct 08, 2007 at 11:33:12PM -0600, Sebastian Kuzminsky wrote: > > What kind of leadscrews are you using? > > they are the 1mm pitch triangular thread that came on the machine. > > This gives a scale of 6000 counts/mm, too high for software counting

Re: [Emc-users] hal servo questions

"Peter C. Wallace" <[EMAIL PROTECTED]> wrote: > BTW we have several of the what I think are same type of motors (19.1V, 500 > count encoder) The ones we have come from HP 7540? plotters. Yeah, they seem like fairly common motors. Are you using yours as servos by any chance? I'm curious, what ki

Re: [Emc-users] hal servo questions

On Tue, 2007-10-09 at 10:33 -0600, Sebastian Kuzminsky wrote: ... snip > > I don't have an oscilloscope, just a cheap multimeter, so I don't think > > I can accurately measure the current just at spinup time. > > Or wait, would this work? I'll put the ammeter inline with one of > the motor leads,

Re: [Emc-users] hal servo questions

On Tue, 9 Oct 2007, Sebastian Kuzminsky wrote: > Date: Tue, 09 Oct 2007 10:33:38 -0600 > From: Sebastian Kuzminsky <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > > To: "Enhanced Machine Controller (EMC)" > Subject: Re: [E

Re: [Emc-users] hal servo questions

On Tue, 9 Oct 2007, Sebastian Kuzminsky wrote: > Date: Tue, 09 Oct 2007 00:07:08 -0600 > From: Sebastian Kuzminsky <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > > To: "Enhanced Machine Controller (EMC)" > Subject: Re: [

Re: [Emc-users] hal servo questions

Jon Elson <[EMAIL PROTECTED]> wrote: > You need a lot more voltage supplying the H bridge. At 55% duty > cycle, you are getting 12 * 0.55 = 6.6 V at the motor. I am a > little surprised the motor doesn't start to turn before this, it > must have a lot of friction. Have you measured the motor

Re: [Emc-users] hal servo questions

Sebastian Kuzminsky <[EMAIL PROTECTED]> wrote: > Jon Elson <[EMAIL PROTECTED]> wrote: > > You need a lot more voltage supplying the H bridge. At 55% duty > > cycle, you are getting 12 * 0.55 = 6.6 V at the motor. I am a > > little surprised the motor doesn't start to turn before this, it > > m

Re: [Emc-users] hal servo questions

Sebastian Kuzminsky wrote: > The next step was to spin the motor, and that's where I'm running into > issues. At 0% duty cycle the motor is stopped, and at 100% it runs fast, > so that's good. However, the mapping from duty-cycle to rpm is confusing. > Duty cycles from 0 to about 55% give me incr

Re: [Emc-users] hal servo questions

On Mon, Oct 08, 2007 at 11:33:12PM -0600, Sebastian Kuzminsky wrote: > > Mine is an 8322, yours is a 9413, I can read the label in this picture: > > > The current lineup of 9xxx motors have much more torque than the > 8xxx series motor I'm

Re: [Emc-users] hal servo questions

"Peter C. Wallace" <[EMAIL PROTECTED]> wrote: > What is happening is this: Thanks for the explanation, that helped a lot, I think I got most of it. :-) > To solve your problem there are a couple of things to try: > > 1. Live with it and offset you PDM As you say, it actually works ok with the

Re: [Emc-users] hal servo questions

Chris Radek <[EMAIL PROTECTED]> wrote: > On Mon, Oct 08, 2007 at 07:51:59PM -0600, Sebastian Kuzminsky wrote: > > reference voltage: 19.1 V DC > > no-load current: 0.16 A > > Peak/Stall Current: 2.51 A > > I think these are the same motors I'm using on my sherline lathe. Mine is an 83

Re: [Emc-users] hal servo questions

SNIP_ > > > The next step was to spin the motor, and that's where I'm running into > issues. At 0% duty cycle the motor is stopped, and at 100% it runs fast, > so that's good. However, the mapping from duty-cycle to rpm is conf

Re: [Emc-users] hal servo questions

On Mon, Oct 08, 2007 at 07:51:59PM -0600, Sebastian Kuzminsky wrote: > reference voltage: 19.1 V DC > no-load current: 0.16 A > Peak/Stall Current: 2.51 A I think these are the same motors I'm using on my sherline lathe. > Duty cycles from 0 to about 55% give me increasing whining fro

[Emc-users] hal servo questions

Hi folks, I'm trying to build my first EMC-controlled servo, and I've got some questions. I'm building it out of a small brushed DC motor (a Pittman 8322 with shaft encoder [0]) and a home-made copy of Jeff Epler's L298-based servo driver [1]. I'm controlling it with EMC 2.1.6, feeding it PDM & di