Re: [Emc-users] Anyone has a rotary table on a mill as 4th axis?
yes On Mon, Aug 2, 2010 at 12:54 AM, Igor Chudov wrote: > Got my Troyke CNC rotary table moving today. eBay item 120587743949, > for details see > > > http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/ > > Anyway, I wanted to use it as a 4th axis. Does anyone have a sample > config for a 4th axis? > > How do you practically home a rotary table if it has no home switch? > Just add one? > > thanks > > i > > > -- > The Palm PDK Hot Apps Program offers developers who use the > Plug-In Development Kit to bring their C/C++ apps to Palm for a share > of $1 Million in cash or HP Products. Visit us here for more details: > http://p.sf.net/sfu/dev2dev-palm > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- dos centavos -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Anyone has a rotary table on a mill as 4th axis?
Got my Troyke CNC rotary table moving today. eBay item 120587743949, for details see http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/ Anyway, I wanted to use it as a 4th axis. Does anyone have a sample config for a 4th axis? How do you practically home a rotary table if it has no home switch? Just add one? thanks i -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Test Results.
Fun! Congrats! Keep the dill cool! i On Mon, Aug 2, 2010 at 12:16 AM, Speaker To-Dirt wrote: > Hi All: > > 'drilled' 140 holes in air, no blown fuses. Tomorrow, metal. > > Sigh. > Thanks. > Andrew > > > > > > > -- > The Palm PDK Hot Apps Program offers developers who use the > Plug-In Development Kit to bring their C/C++ apps to Palm for a share > of $1 Million in cash or HP Products. Visit us here for more details: > http://p.sf.net/sfu/dev2dev-palm > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Test Results.
Hi All: 'drilled' 140 holes in air, no blown fuses. Tomorrow, metal. Sigh. Thanks. Andrew -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Bridgeport Series 1 Fuse Popping Problem Solved?
Speaker To-Dirt wrote: > Hey Everyone: > > I ran through the tests in the service manual that you folks said I should > do. My transformer outputs look good. But the quiescent AC current on each > stepper was set at 10.2A instead of the 8.1 - 8.4A called for. Why so > uniform? It almost makes me think that the previous owner poured more current > through these things to make up for old weaker magnets? No, he probably set it for the local line voltage. If the machine had been running on 208 V it would almost account for the difference. 208/240 = 0.87 and 8.4 / 10.2 = 0.82 Turning up the current won't make the steppers run better, it will make them run worse, in most cases. Oh, one other possible explanation is the current was improperly set by a tech some time in the past. There were some other BOSS motors that did run at 10-11 A. But, if your motors are really supposed to run at 8.25 A nominal, then you had it on a 24% excess, which is a hell of a lot. > Why the uniform values way too high? I tweaked them all down into spec on > the ACC board. I'm testing on air as I write this. I'll test under load > tomorrow. So Jon, thanks to you for driving me in this direction. Now I'm > nervous > Why nervous? Your machine survived something that could have fried a bunch of transistors or even the motors. But, you got lucky and all it did was pop some fuses. It is pretty likely that it will NOT blow fuses any more! Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
Alex Joni wrote: > That means you can't jog before homing... > Well, if you made tiny jogs in each direction, small enough so that they didn't cause a following error, then the servo amp would go live and all would be fine. That's why I put this in the driver so it just got done immediately after coming out of E-stop, and took care of the problem. I emailed Anders Wallin to see how he dealt with this, but haven't heard back yet. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
Andy Pugh wrote: > On 1 August 2010 18:44, Jon Elson wrote: > > >> Our amps DO, indeed, have such a supply. But, this one pulse each way >> thing is needed to clear the shutdown latch in the IR FET driver chip. >> > > Would setting the direction to be opposite to the home direction in > the HAL suffice? > ie, at startup the direction is set one way, then homing sets it the > other way, at which the drive comes up and homing starts. > Hmmm, as long as the PID routine is outputting a non-zero PWM value, then just flipping the direction would sure do it. The PWM pulse needs to be wide enough to make it through the opto-isolator, so somewhere around 5% duty cycle would be ideal, but anything over 2.5% should work (that will give a 500 ns pulse at 50 KHz frequency). This is essentially what I do in my driver. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Bridgeport Series 1 Fuse Popping Problem Solved?
Hey Everyone: I ran through the tests in the service manual that you folks said I should do. My transformer outputs look good. But the quiescent AC current on each stepper was set at 10.2A instead of the 8.1 - 8.4A called for. Why so uniform? It almost makes me think that the previous owner poured more current through these things to make up for old weaker magnets? Why the uniform values way too high? I tweaked them all down into spec on the ACC board. I'm testing on air as I write this. I'll test under load tomorrow. So Jon, thanks to you for driving me in this direction. Now I'm nervous I just did an index test and it seems to not be skipping a beat. But I'll be happy if it's still working next week. Thanks Everyone! Andrew -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
On 8/2/2010 2:06 AM, Andy Pugh wrote: > On 1 August 2010 18:44, Jon Elson wrote: > > >> Our amps DO, indeed, have such a supply. But, this one pulse each way >> thing is needed to clear the shutdown latch in the IR FET driver chip. >> > Would setting the direction to be opposite to the home direction in > the HAL suffice? > ie, at startup the direction is set one way, then homing sets it the > other way, at which the drive comes up and homing starts. > > That means you can't jog before homing... -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
On 1 August 2010 18:44, Jon Elson wrote: > Our amps DO, indeed, have such a supply. But, this one pulse each way > thing is needed to clear the shutdown latch in the IR FET driver chip. Would setting the direction to be opposite to the home direction in the HAL suffice? ie, at startup the direction is set one way, then homing sets it the other way, at which the drive comes up and homing starts. -- atp -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
On Sunday, August 01, 2010 05:40:41 pm Alex Joni did opine: > I used these in the past along with some IRFZ44N > http://www.irf.com/product-info/datasheets/data/irf4905.pdf > Wow Alex, I obviously need to update my library, that looks like a quite decent P channel device. [...] -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Pollyanna's Educational Constant: The hyperactive child is never absent. -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
On Sunday, August 01, 2010 05:19:09 pm Jon Elson did opine: > Gene Heskett wrote: > > By normal fab techniques, there is not a P type FET, they all need a + > > signal on the gate to turn them on. That said, a separate + and - 5 > > volt supply winding whose center tap rail is common to the FET's > > source rail is the much preferred method of deriving the high sides > > on pulse drive voltage. I generally detest the bootstrap methods > > because the voltage so developed isn't as dependable (IMO). The > > capacitors that are the isolation/storage elements of a bootstrapped > > circuit are usually common electrolytics, with their failure rates > > being 100x that of the semiconductors involved. When a semiconductor > > in one of these circuits fails, there is about a 100/1 chance a > > failing capacitor was the first circuit fault. > > 5 V isn't enough bias, I use 12 V. Does that not add to the stored charge, lengthening the turnoff times? > I use a 0.1 uF SMT ceramic cap for > the bootstrap capacitor. I TBT was thinking along the lines of a small electrolytic in order to cover the frequency range of the VFD at slow speeds. Those should never be discussed in the same book as dependable. > That is plenty of charge as it is recharged every 20 us. I have never > had one of these caps fail. > The FET driver chips have an undervoltage lockout, so it will not even > turn on if the supply is too low. > If you go to 100% PWM duty cycle, this will eventually happen, and the > drive handles it gracefully > and just goes "limp". Hitting E-stop and resetting it clears the > trouble. > > > Driving a power FET is almost a separate chapter in the design tomes, > > as the gates in high powered versions of these can represent quite a > > large capacitance just from the sheer size of all the actual gates in > > the devices, with figures well above .05 microfarads, some of which > > gets amplified by miller feedback effects as its turned on and off. > > In order to minimize the junction heat during the on-off or off-on > > transitions, the driving waveform must be very fast, and capable of > > charging or discharging that large capacitance in nanoseconds. That > > implies a driver capable of several amps with rise & fall times of 10 > > or so nanoseconds. Many a power FET aka HEXFET has been destroyed by > > drivers that take a microsecond to make that nominally 9 volt swing. > > 5 volt + to fully turn them on, and about -4 to turn them absolutely > > off in the shortest time. > > > > I'm with Kirk on this one, we are a relatively small market, one that > > will never find a profit in 'simplicating' the right way out of a > > circuit, so it should be done right, not to consumer grade standards > > but better. > > I figure that I'd have to raise the price on my servo amps by $100 each > to cover the cost of winding the transformer by hand, and providing the > extra components for it. That's completely out of the question to solve > a problem that doesn't even exist. Despite the name of this PPMC driver > feature, it actually has NOTHING to do with bootstrap power supplies. That puts a different complexion on it entirely, thanks Jon. What I had in mind, and which does a bootstrap thing for both capacitor charge and transformer core reset, is a circuit similar to that which drives the H scan circuitry on older crt monitors. It is 'bootstrapped' in the sense that the bottom winding end of the driver transformers secondary, a teeny little ferrite thing, is tied to the hexfets src terminal, and IIRC a small, say 4.7 ohm resistor is used to limit gate current during the on period, the current then flowing in reverse through another diode when the driver transistor is turned off. Turn on time is about 15ns, turnoff time about 50ns. And its a none too reliable circuit that I'd not ever use in a fresh design. I think it could be made reliable, but I've not found that 'magic twanger' yet. It has 4 or 5 electrolytic caps in it, and any one of them developing an ESR above 2 ohms and the whole circuit goes up in smoke. > Jon > > > -- The Palm PDK Hot Apps Program offers developers who use the > Plug-In Development Kit to bring their C/C++ apps to Palm for a share > of $1 Million in cash or HP Products. Visit us here for more details: > http://p.sf.net/sfu/dev2dev-palm > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) A diplomat is a person who can tell you to go to hell in such a way that you actually look forward to the trip. -- Caskie Stinnett, "Out of the Red" -
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
Alex Joni wrote: > I used these in the past along with some IRFZ44N > http://www.irf.com/product-info/datasheets/data/irf4905.pdf > > This is a 55 V transistor. At 200 V they are at least unobtainable at reasonable cost. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Run from Flash Newbie Question.
My current system boots up on Flash but does not save any of the changes. Is there a way to boot on Flash, run in memory and then save changes back to Flash for the next boot? Bob Moors Weatherford Tx -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Fresh RPC values.
I am guessing that he does and his run caps also start the motor. I had this before and it was similarly unbalanced asymmetrically. On Aug 1, 2010 12:14 PM, "Jon Elson" wrote: Igor Chudov wrote: > Are your run caps connected to one leg only? > I'm guessing there are NO run caps in this RPC. Jon -- The Palm PDK Ho... -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
Peter C. Wallace wrote: > Yes, this is the high side gate supply voltage. Well, no, despite the name, it actually has nothing to do with the bootstrap supply. Our amps DO, indeed, have such a supply. But, this one pulse each way thing is needed to clear the shutdown latch in the IR FET driver chip. The bootstrap supplies are kept charged any time the PWM signal is at "off", so that's every PWM cycle. I know Anders Wallin in Finland is using my servo amps with the Mesa controller, but I can't find a copy of his hal files to see if he did anything special to solve this problem. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Quieting The Variable Frequency Drive (VFD) Noise.How To.
rng3 wrote: > When working with a typical 2 - 3 hp mill and our main goal is to reduce > noise that might effect our limit switches, encoders etc. with a 3 phase VFD > installation where would we start, line reactor, filter, or both. Any > recommend sources? Success stories? > Depends on where the problem is really coming from. The first thing to do is provide a heavy ground conductor to the machine frame. Make sure nothing else is grounded to the machine frame, such as at limit switches, encoders, etc. if possible. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
I used these in the past along with some IRFZ44N http://www.irf.com/product-info/datasheets/data/irf4905.pdf Regards, Alex On 8/1/2010 8:27 PM, Jon Elson wrote: > Kirk Wallace wrote: > >> Is this the high side bootstrap that creates the high side FET gate >> control voltage? >> > No, not really. That may be where John Kasunich got the name to call it > the "bootstrap" > parameter of the driver (I didn't supply that name to him). These servo > amps do have such a bootstrap > scheme to supply the high side bias. But, what this one pulse each > direction thing does is to reset the shutdown latches in the IR2113S FET > driver chips. I would have been fine without such a latch, but it is a > feature of the chip, I can't change it. When the positioning loop > starts up, EMC may decide the motor needs to move in one direction to > null the error, and if the amp hasn't seen at least one tiny pulse in > the opposite direction, it won't produce any output. > >> This has always seemed to create more trouble than it >> is worth. Why not have another supply with the proper voltage and not >> have to deal with the bootstrap? Or use N and P FET's? I know the >> bootstrap method may save a portion of the parts cost, but for the >> product quantities for the CNC market, it doesn't seem worth it. I may >> be showing my ignorance here. >> >> > I really don't see it as a problem. It does mean you can't go to 100.0% > duty cycle, somewhere around 95% is a good limit. > I did put a high-side supply on my first generation servo amp. It > required winding a custom transformer, and having a power > driver circuit for it. The reason is this is not just a fixed voltage a > little above the motor supply voltage, it is a FLOATING supply that > tracks the source terminal of the high-side FET. So, this whole power > supply swings the entire range of the motor supply in 200 ns or so, > every time the transistors switch. And, you need TWO of them, one for > each high side transistor. The capacitive coupling between the drive > winding and the output windings causes problems with blowing out the > driver chip, so isolation of the windings is needed. A TOTAL pain! So, > that's why these bootstrap circuits are so popular, they work and are > elegantly simple. > > Using P-channel FETS would work, and avoid the loating supplies, > but. I use 40 milli-Ohm transistors in my drives. Try to find a > 200 V 40 mOhm P-channel FET. > They don't exist. > > Jon > > -- > The Palm PDK Hot Apps Program offers developers who use the > Plug-In Development Kit to bring their C/C++ apps to Palm for a share > of $1 Million in cash or HP Products. Visit us here for more details: > http://p.sf.net/sfu/dev2dev-palm > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
Gene Heskett wrote: > > > By normal fab techniques, there is not a P type FET, they all need a + > signal on the gate to turn them on. That said, a separate + and - 5 volt > supply winding whose center tap rail is common to the FET's source rail is > the much preferred method of deriving the high sides on pulse drive > voltage. I generally detest the bootstrap methods because the voltage so > developed isn't as dependable (IMO). The capacitors that are the > isolation/storage elements of a bootstrapped circuit are usually common > electrolytics, with their failure rates being 100x that of the > semiconductors involved. When a semiconductor in one of these circuits > fails, there is about a 100/1 chance a failing capacitor was the first > circuit fault. > > 5 V isn't enough bias, I use 12 V. I use a 0.1 uF SMT ceramic cap for the bootstrap capacitor. That is plenty of charge as it is recharged every 20 us. I have never had one of these caps fail. The FET driver chips have an undervoltage lockout, so it will not even turn on if the supply is too low. If you go to 100% PWM duty cycle, this will eventually happen, and the drive handles it gracefully and just goes "limp". Hitting E-stop and resetting it clears the trouble. > Driving a power FET is almost a separate chapter in the design tomes, as > the gates in high powered versions of these can represent quite a large > capacitance just from the sheer size of all the actual gates in the > devices, with figures well above .05 microfarads, some of which gets > amplified by miller feedback effects as its turned on and off. In order to > minimize the junction heat during the on-off or off-on transitions, the > driving waveform must be very fast, and capable of charging or discharging > that large capacitance in nanoseconds. That implies a driver capable of > several amps with rise & fall times of 10 or so nanoseconds. Many a power > FET aka HEXFET has been destroyed by drivers that take a microsecond to > make that nominally 9 volt swing. 5 volt + to fully turn them on, and > about -4 to turn them absolutely off in the shortest time. > > I'm with Kirk on this one, we are a relatively small market, one that will > never find a profit in 'simplicating' the right way out of a circuit, so it > should be done right, not to consumer grade standards but better. > I figure that I'd have to raise the price on my servo amps by $100 each to cover the cost of winding the transformer by hand, and providing the extra components for it. That's completely out of the question to solve a problem that doesn't even exist. Despite the name of this PPMC driver feature, it actually has NOTHING to do with bootstrap power supplies. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
Kirk Wallace wrote: > Is this the high side bootstrap that creates the high side FET gate > control voltage? No, not really. That may be where John Kasunich got the name to call it the "bootstrap" parameter of the driver (I didn't supply that name to him). These servo amps do have such a bootstrap scheme to supply the high side bias. But, what this one pulse each direction thing does is to reset the shutdown latches in the IR2113S FET driver chips. I would have been fine without such a latch, but it is a feature of the chip, I can't change it. When the positioning loop starts up, EMC may decide the motor needs to move in one direction to null the error, and if the amp hasn't seen at least one tiny pulse in the opposite direction, it won't produce any output. > This has always seemed to create more trouble than it > is worth. Why not have another supply with the proper voltage and not > have to deal with the bootstrap? Or use N and P FET's? I know the > bootstrap method may save a portion of the parts cost, but for the > product quantities for the CNC market, it doesn't seem worth it. I may > be showing my ignorance here. > I really don't see it as a problem. It does mean you can't go to 100.0% duty cycle, somewhere around 95% is a good limit. I did put a high-side supply on my first generation servo amp. It required winding a custom transformer, and having a power driver circuit for it. The reason is this is not just a fixed voltage a little above the motor supply voltage, it is a FLOATING supply that tracks the source terminal of the high-side FET. So, this whole power supply swings the entire range of the motor supply in 200 ns or so, every time the transistors switch. And, you need TWO of them, one for each high side transistor. The capacitive coupling between the drive winding and the output windings causes problems with blowing out the driver chip, so isolation of the windings is needed. A TOTAL pain! So, that's why these bootstrap circuits are so popular, they work and are elegantly simple. Using P-channel FETS would work, and avoid the loating supplies, but. I use 40 milli-Ohm transistors in my drives. Try to find a 200 V 40 mOhm P-channel FET. They don't exist. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Reactors.
Speaker To-Dirt wrote: > Hi All: > >Okay, so the question about what drives the current for the reactor > control winding. Here we go BOSS Service Manual p4-76 > > Looking at Figure 1040215, it can be seen that the emitters of the drive > transistors are returned to ground through resistors R1 and R2. A voltage > proportional to motor current is developed across these resistors and fed to > the ACC input at pins 9, 35, and 34. Looking at just the X-axis portion, see > that a portion of the apmplifiger Q5-Q4, where it is compared to the voltage > across the two forwrd-biased diodes D19 and D20. When it exceeds the diode > voltage Q5 will start to turn on and Q4 to turn off. This loweres the base > voltage of the PNP transistor Q3, turning it on and pulling up the base of > Q2. Q2 now turns on and pulls the base of Q22 down, turning it off and Q1 > with it. Q1 controls the DC through the control winding of the saturable > reactor; turning if off stops the control current and causes the pmpedance of > the power winding to increase greatly. > > I think this is where I'll start probing tomorrow. Thanks for pointing me in > this direction guys, it does look like it could cause my problem. But I'm > happy to see that the saturation control current is not under CPU control ... > that's good because I have not taken any steps to control it. And it also > means my memory is still somewhat sound. > OK, so it is an active current control scheme, I didn't know that. I think maybe some people rip out the ACC board when doing their conversion, obviously a mistake. When this circuit is working, it has to be better than a plain on-off control of the reactor. Lucky you have the manual for this, it would be almost impossible to figure it out without that. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Fresh RPC values.
Igor Chudov wrote: > Are your run caps connected to one leg only? > I'm guessing there are NO run caps in this RPC. Jon -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 controller
On Sat, 31 Jul 2010, Kirk Wallace wrote: > Date: Sat, 31 Jul 2010 21:46:44 -0700 > From: Kirk Wallace > Reply-To: "Enhanced Machine Controller (EMC)" > > To: "Enhanced Machine Controller (EMC)" > Subject: Re: [Emc-users] Use of Pico Systems PWM servo amp with Mesa 5i20 > controller > > On Sat, 2010-07-31 at 23:15 -0500, Jon Elson wrote: >> I know a number of people are using my PWM servo amps with Mesa >> controller boards. >> A feature of the dumb control logic on the servo amp is that it needs a >> short pulse in each direction >> to clear the shutdown latches on the FET driver chips. I built a little >> state machine into the driver to accomplish this, it is called the >> "bootstrap" parameter. It gives 5% duty cycle pulses in each direction >> on consecutive servo cycles, then goes to normal operation as commanded >> by the PWM input. If you don't do this, the drive can act like it is >> disabled until you attempt to move it both directions, then it will >> suddenly come "live". >> >> So, has anyone written up a couple lines of HAL to do this, or how else >> do you solve the problem? >> >> (This applies only to the brush version of the servo amp, the brushless >> amp has a CPLD that manages this function.) >> >> Thanks, >> >> Jon > > Is this the high side bootstrap that creates the high side FET gate > control voltage? This has always seemed to create more trouble than it > is worth. Why not have another supply with the proper voltage and not > have to deal with the bootstrap? Or use N and P FET's? I know the > bootstrap method may save a portion of the parts cost, but for the > product quantities for the CNC market, it doesn't seem worth it. I may > be showing my ignorance here. > -- > Kirk Wallace > http://www.wallacecompany.com/machine_shop/ > http://www.wallacecompany.com/E45/index.html > California, USA > Yes, this is the high side gate supply voltage. We have PWM amps that use separate supplies (7I27) and bootstrap supplies (7I30,7I29, 8I20). The advantages of the bootstrap supply are that it is cheaper and has fewer components. Supplying the top MOSFET gate power is awkward because the power supply is floating on the high side MOSFETs (or IGBTs) source electrode. This source electrode is switching at ~10 to 100 KHz with full motor bus voltage so the supply must be isolated for the full motor power supply voltage switching with a high frequency square wave. Because the high side gate power supplies are referenced to each MOSFET source, each high side MOSFET gate driver needs a separate supply (so a HBridge needs 2 separate high side gate supplies and a 3 phase bridge needs 3). If separate high side gate supplies are used, this adds considerable cost and complexity (and lowers reliability). Its certainly possible to have a high voltage transformer coupled isolated DC supply for each high side gate driver (like our 7I27) but whether its a good design decision is open to arguement. The disadvantage of boostrap PWM is than you cannot have 100% output duty cycle. Normally you will be limited to about 95-98% (depending on switching speeds, PWM rates, etc) This is because each HBridge legs lower MOSFET must turn on for some portion of time to charge the boostrap capacitors. For 3 phase drives it is possible to get 100% output from a bootrap supplied bridge at medium-high motor speeds (where you may need the 100%) because the normal phase rotation will charge the bootstrap capacitors. Peter Wallace Mesa Electronics -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Quieting The Variable Frequency Drive (VFD) Noise.How To.
You can throw all kinds of devices at your project to try and reduce noise, but the fact remains that VFDs can be very noisy devices. I'd concentrate on properly grounding your system via a central star ground setup in your panel, and try and route the power, particularly the VFD motor lead wiring away from the lower voltage signal wiring. Start everything up and see what you have. Don't run your VFD motor leads wires in the same conduit, sealtite, or wireway in the panel with encoder cables or low voltage control wires. Buying input and output filters, may or may not be required. A dedicated AC transformer for the VFD will act as an input filter. I try and mount all of the power components at the top of the panel where the power enters the panel and put the computer and low voltages devices near the bottom. A lot of systems can get by without any filter devices at all if you are careful in how you wire the system. Dave On 8/1/2010 8:07 AM, rng3 wrote: > When working with a typical 2 - 3 hp mill and our main goal is to reduce > noise that might effect our limit switches, encoders etc. with a 3 phase VFD > installation where would we start, line reactor, filter, or both. Any > recommend sources? Success stories? > > > -- > The Palm PDK Hot Apps Program offers developers who use the > Plug-In Development Kit to bring their C/C++ apps to Palm for a share > of $1 Million in cash or HP Products. Visit us here for more details: > http://p.sf.net/sfu/dev2dev-palm > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Quieting The Variable Frequency Drive (VFD) Noise.How To.
When working with a typical 2 - 3 hp mill and our main goal is to reduce noise that might effect our limit switches, encoders etc. with a 3 phase VFD installation where would we start, line reactor, filter, or both. Any recommend sources? Success stories? -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] 3 questions. 1-Stopping automatic updates. 2-Forced loading versions. 3-G00 moves with EMC 2.3.5 and 2.4.2
On 1 August 2010 03:17, Don Stanley wrote: > It was Kicked in on EMC 2.3.5. On a whim I checked to see if the X (axis 0) > controlled the max speed for all axis. Apparently it does. Where does the HAL file look when setting up the Z speed? -- atp -- The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
