Re: [Emc-users] parameters
for master, I've expanded the parameters section quite a bit, and I did it in 'G-Code Overview' for numbered and named parameters http://www.linuxcnc.org/docs/devel/html/gcode/overview.html#_a_id_sec_parameters_a_parameters_variables_in_g_code_programs note the named parameter stuff is applicable to master, not earlier branches -m, Am 12.12.2011 um 18:43 schrieb andy pugh: On 12 December 2011 17:34, Ralph Stirling ralph.stirl...@wallawalla.edu wrote: I've been studying the documentation and the source code for information on G-code readable/writeable parameters. I have yet to find a good summary of all the defined parameters in a single place. So far, I've found #5161-#5390 and #5400-#5428 defined in interp_array.cc. #5061-5070 are defined in interp_internal.cc, and rs274ngc_pre.cc defines #5599 to #5601 and #5399 to #5413. Some of these are mentioned in the G Code Reference manual. Have I missed any? I think most of them are here: http://www.linuxcnc.org/docview/2.5/html/common/machining_center.html#_parameters_a_id_sub_parameters_a Though I agree that isn't the most obvious place to look. -- atp The idea that there is no such thing as objective truth is, quite simply, wrong. -- Learn Windows Azure Live! Tuesday, Dec 13, 2011 Microsoft is holding a special Learn Windows Azure training event for developers. It will provide a great way to learn Windows Azure and what it provides. You can attend the event by watching it streamed LIVE online. Learn more at http://p.sf.net/sfu/ms-windowsazure ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] [OT]elettromagnetic brakes
Hi, and sorry for the ot question, but maybe your knowledge can help me. Do you know of someone selling cheap safety brakes, to be mounted on the back shaft of a stepper motor, with a torque of 570oz/in (about 4N/mt). I mean those when if current goes off they brake. Thank for any suggestion, Davide. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Thanks for the info Jon. We are seeing a small (about 0.001) position error just on initial acceleration and deceleration that we cannot account for. It may be due to the encoder. Since this is mainly a plasma machine we will probably live with it. If we need to do better we'll look at replacing the encoders. We now know the string attached to our cheap encoder :-) -Tom On Dec 13, 2011, at 12:21 AM, Jon Elson wrote: Yes, that is EXACTLY the kind of problem I saw. This encoder is highly interpolated, so it has a tracking counter that is incremented or decremented by an estimate of the current velocity. If you don't do these computations correctly, there is a lag in responding to changes in velocity. As far as I can tell, the interpolator in such devices as the Analog Devices AD2S1200 has a really fine 2nd or 3rd order filter to make this work well. Obviously, CUI did not go to the trouble of such mathematics. After never being happy with these encoders and having a bit of customer feedback, I decided to compare to a standard HP optical encoder (with no interpolation.) So, I put the optical encoder on the other end of the motor, and fed both to encoder inputs on my PWM controller board. Most useful was to plot velocity derived from both encoders at the same time. This comes up often enough, I have the plots permanently on my web site. See http://pico-systems.com/images/compare_encoder2.png The red trace is the CUI encoder, which was controlling the motor (badly). The white trace is the HP encoder. Both are providing 4000 counts/rev. You can clearly see the velocity peaks of the CUI encoder are higher, and if you look closely at the slopes, you can see the CUI is slow to react to velocity changes, and then has to overshoot significantly so the position can catch up. This of course accounts for the bad servo behavior. As the Halscope is set for 20 ms/div, the velocity lag is easily 3-5 ms in duration! If you have a plain optical encoder handy, you could easily set up the same arrangement to compare the encoders. Jon -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Tue, 13 Dec 2011, Tom Easterday wrote: Date: Tue, 13 Dec 2011 11:45:41 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Encoders Thanks for the info Jon. We are seeing a small (about 0.001) position error just on initial acceleration and deceleration that we cannot account for. It may be due to the encoder. Since this is mainly a plasma machine we will probably live with it. If we need to do better we'll look at replacing the encoders. We now know the string attached to our cheap encoder :-) -Tom Have you tried using FF2 to tune out the lag/lead during accel/decel? (a jerk limited profile would also help) Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your ()_() signature to help him gain world domination. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Viesturs Lācis wrote: 2011/12/13 Jon Elson el...@pico-systems.com: Watch out for the CUI AMT-10x encoders at Digi-Key, they have a lag responding to acceleration, and may not be well-suited to CNC systems such as EMC2. Thanks for the warning, Jon! I happen to have bought these encoders for one of the machines... Do I understand correctly that they are working fine, but I will need to decrease max acceleration to get better performance of the encoder? The problem is there is a lag between acceleration and the encoder responding to it. If your servo loop can be tuned for good performance, you are lucky. The more massive the load, the better, I guess. The worst case is a low-inertia motor sitting on the bench. But, if you cannot get the loop response tuned properly, then there really is nothing you can do to fix that. The problem is that when velocity changes, the encoder does not correctly report position. It reports what the position WOULD have been if there had not been an acceleration. Decreasing max accel will help prevent exciting any unstable response from G-code, but external forces acting on the system cannot be controlled that way, and may excite instability. In other words, reducing accel masks the problem, instead of solving it. Reducing gain will help, but can make the servo response less accurate. Jon -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Dec 13, 2011, at 12:52 PM, Peter C. Wallace wrote: On Tue, 13 Dec 2011, Tom Easterday wrote: Date: Tue, 13 Dec 2011 11:45:41 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Encoders Thanks for the info Jon. We are seeing a small (about 0.001) position error just on initial acceleration and deceleration that we cannot account for. It may be due to the encoder. Since this is mainly a plasma machine we will probably live with it. If we need to do better we'll look at replacing the encoders. We now know the string attached to our cheap encoder :-) -Tom Have you tried using FF2 to tune out the lag/lead during accel/decel? Yes. Peter (working with me) spent a long time playing with FF2. We were seeing large spikes at first and had FF2 set to 0.007 which helped to lower it to .002-.003. We then realized we had the Granite Devices input filtering (which introduces a delay and is documented as doing so) turned on. Turning that off has allowed us to lower FF2 to 0.000105, not zero but getting there. The remainder of the delay is now (possibly) coming from the encoder issue Jon has pointed out. (a jerk limited profile would also help) What'd you call me? :-) What is a jerk limited profile? -Tom -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Tom Easterday wrote: Thanks for the info Jon. We are seeing a small (about 0.001) position error just on initial acceleration and deceleration that we cannot account for. It may be due to the encoder. Since this is mainly a plasma machine we will probably live with it. If we need to do better we'll look at replacing the encoders. We now know the string attached to our cheap encoder If you can send me a picture form Halscope, I can compare it to what I get. Are you using FF2? This can be quite helpful in fixing errors on acceleration. You have to use it in VERY small amounts, though, like .005 or even less. It is easy to add too MUCH FF2 and cause jerks in the response. Also, there is a manufacturing issue in these, where the encoder ring may fit loosely on the splined hub that mounts to the shaft. On some units you need to put a little dab of RTV, super glue or whatever on the splined hub to lock the ring to it. You can poke the ring with an X-acto knife to see if there is any play between it and the hub when the whole thing is assembled. Jon -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] [OT]elettromagnetic brakes
On 12/13/2011 8:41 AM, Spiderdab wrote: Hi, and sorry for the ot question, but maybe your knowledge can help me. Do you know of someone selling cheap safety brakes, to be mounted on the back shaft of a stepper motor, with a torque of 570oz/in (about 4N/mt). I mean those when if current goes off they brake. Thank for any suggestion, Davide. Cheap and Safety don't normally go together. ;-) What do you consider cheap? I'd like to find a less expensive holding brake for Nema 34 steppers, something in the $100 range would be nice. I found these. http://www.damencnc.com/en/components/motors-and-drivers/motor-add-ons/252 http://www.electroid.com/prod09.htm Dave -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Dec 13, 2011, at 1:02 PM, Jon Elson wrote: The more massive the load, the better, I guess. The worst case is a low-inertia motor sitting on the bench. Yes, this is an important point - that we have learned the hard way. We were about to throw in the towel trying to tune our machine. We have some fairly torquey (I can't believe that is actually a word:-) ) motors given the mass of the machine. We finally got a little education on servos and ended up changing our gearing from 2:1 to 5:1 (and using an initial 10:1 gearbox attached to the motor). This made ALL the difference in the world. The machine runs smooth as silk now as there is a constant load on the motor to overcome the 10:1 gearing. Tom -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Dec 13, 2011, at 1:09 PM, Jon Elson wrote: If you can send me a picture form Halscope, I can compare it to what I get. Are you using FF2? This can be quite helpful in fixing errors on acceleration. You have to use it in VERY small amounts, though, like .005 or even less. It is easy to add too MUCH FF2 and cause jerks in the response. Yes, see post in response to Peter Wallace. Also, there is a manufacturing issue in these, where the encoder ring may fit loosely on the splined hub that mounts to the shaft. On some units you need to put a little dab of RTV, super glue or whatever on the splined hub to lock the ring to it. You can poke the ring with an X-acto knife to see if there is any play between it and the hub when the whole thing is assembled. Mariss from Gecko suggested this to me early on, so we super glued the collars to the shafts. This did indeed help a little, one of them was slipping badly, the others perhaps a small amount. He also suggested adding a tiny bit of silicone caulk to one of the cogs in the gear to take up any slop in the fit (both pieces are plastic after all). I did that as well, but I don't think there was much slop to begin with so that provided no noticeable improvement. -Tom -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Tue, 13 Dec 2011, Tom Easterday wrote: Date: Tue, 13 Dec 2011 13:06:31 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Encoders On Dec 13, 2011, at 12:52 PM, Peter C. Wallace wrote: On Tue, 13 Dec 2011, Tom Easterday wrote: Date: Tue, 13 Dec 2011 11:45:41 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Encoders Thanks for the info Jon. We are seeing a small (about 0.001) position error just on initial acceleration and deceleration that we cannot account for. It may be due to the encoder. Since this is mainly a plasma machine we will probably live with it. If we need to do better we'll look at replacing the encoders. We now know the string attached to our cheap encoder :-) -Tom Have you tried using FF2 to tune out the lag/lead during accel/decel? Yes. Peter (working with me) spent a long time playing with FF2. We were seeing large spikes at first and had FF2 set to 0.007 which helped to lower it to .002-.003. We then realized we had the Granite Devices input filtering (which introduces a delay and is documented as doing so) turned on. Turning that off has allowed us to lower FF2 to 0.000105, not zero but getting there. The remainder of the delay is now (possibly) coming from the encoder issue Jon has pointed out. (a jerk limited profile would also help) What'd you call me? :-) What is a jerk limited profile? A cubic profile Currently EMC uses a trapezoidal (linear) velocity profile (so parabolic position profile) This means the acceleration profile is a step function. The beginning of this step is whats hard to tune around (as you have found) Jerk is the derivative of acceleration so is infinite with stepped acceleration (the current situation with EMC). By using a cubic profile where the acceleration is ramped (like velocity is now) starts and stops are much gentler and contain less high frequency components that make it hard to tune -Tom -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your ()_() signature to help him gain world domination. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Tue, 13 Dec 2011, Tom Easterday wrote: Date: Tue, 13 Dec 2011 13:20:28 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Encoders Theres a FAQ fom AMT that mentions a jumper on the card that can be removed to approximately 1/2 the filter time constant (at the expense of more noise) Might be worth a try www.amtencoder.com/Resources/Frequently-Asked-Questions Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your ()_() signature to help him gain world domination. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Dec 13, 2011, at 1:17 PM, Peter C. Wallace wrote: A cubic profile Currently EMC uses a trapezoidal (linear) velocity profile (so parabolic position profile) This means the acceleration profile is a step function. The beginning of this step is whats hard to tune around (as you have found) Jerk is the derivative of acceleration so is infinite with stepped acceleration (the current situation with EMC). By using a cubic profile where the acceleration is ramped (like velocity is now) starts and stops are much gentler and contain less high frequency components that make it hard to tune Thanks Peter. And how/where does one set this as the velocity profile? Tom -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Tue, 13 Dec 2011, Tom Easterday wrote: Date: Tue, 13 Dec 2011 13:44:01 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Encoders On Dec 13, 2011, at 1:17 PM, Peter C. Wallace wrote: A cubic profile Currently EMC uses a trapezoidal (linear) velocity profile (so parabolic position profile) This means the acceleration profile is a step function. The beginning of this step is whats hard to tune around (as you have found) Jerk is the derivative of acceleration so is infinite with stepped acceleration (the current situation with EMC). By using a cubic profile where the acceleration is ramped (like velocity is now) starts and stops are much gentler and contain less high frequency components that make it hard to tune Thanks Peter. And how/where does one set this as the velocity profile? Tom Apply ~0.5 man year to Trajectory Planner -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your ()_() signature to help him gain world domination. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On 13 December 2011 18:44, Tom Easterday tom-...@bgp.nu wrote: Thanks Peter. And how/where does one set this as the velocity profile? It isn't currently an option with EMC2. Though I think at least some work has been done around adding it. -- atp The idea that there is no such thing as objective truth is, quite simply, wrong. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
On Dec 13, 2011, at 1:09 PM, Jon Elson wrote: If you can send me a picture form Halscope, I can compare it to what I get. See: http://bgp.nu/~tom/pub/XPosErr-VelCmd.png These are versions without the velocity command at 250ipm and ~1500ipm: http://bgp.nu/~tom/pub/XPosError-250ipm.png http://bgp.nu/~tom/pub/XPosError-Rpaid.png -Tom -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] newbee?
hey im jeremy been paying attention two this for several months now and am moving forward with my mill. was curious has any body experimented with gm crankshaft sensors? it seems that a tonwheel should be pretty easy even with a manual machine and what is halscope? linux dso? if so what do i need thanx -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] newbee?
On 13 December 2011 23:17, alice aliceyou...@localnet.com wrote: was curious has any body experimented with gm crankshaft sensors? it seems that a tonwheel should be pretty easy even with a manual machine I have considered using a Ford/PSA crank sensor (which is a hall sensor and a magnetic disc) but it would require changes to the Encoder function to handle the missing-tooth index. Dual sensor systems are starting to become common, which do quadrature to track any drop-back of the crank, this is so that crank synch isn't lost during engine shutdown for faster starting in stop-start vehicles. and what is halscope? linux dso? It is a utility built in to EMC2, it allows you to scope any of the internal HAL values (which also includes any of the IO) -- atp The idea that there is no such thing as objective truth is, quite simply, wrong. -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] [OT]elettromagnetic brakes
Il giorno mar, 13/12/2011 alle 13.13 -0500, Dave ha scritto: On 12/13/2011 8:41 AM, Spiderdab wrote: Hi, and sorry for the ot question, but maybe your knowledge can help me. Do you know of someone selling cheap safety brakes, to be mounted on the back shaft of a stepper motor, with a torque of 570oz/in (about 4N/mt). I mean those when if current goes off they brake. Thank for any suggestion, Davide. Cheap and Safety don't normally go together. ;-) I know, but we are talking about a brake for 4N/mt, so it's a little torque.. What do you consider cheap? I'd like to find a less expensive holding brake for Nema 34 steppers, something in the $100 range would be nice. I found these. http://www.damencnc.com/en/components/motors-and-drivers/motor-add-ons/252 http://www.electroid.com/prod09.htm Dave first are very nice, but cost too much! 124€ for one brake! i've found something on rs site, that costs around 78€ per brake, but not with nema size mount. It has the same torque, 3,95N/mt http://it.rs-online.com/web/p/accessori-per-freni-frizioni/2677674/ about the second link, they don't put prices on the site, did you already asked for? -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] newbee?
On Tue, 13 Dec 2011 18:17:07 -0500 alice aliceyou...@localnet.com wrote: hey im jeremy been paying attention two this for several months now and am moving forward with my mill. was curious has any body experimented with gm crankshaft sensors? it seems that a tonwheel should be pretty easy even with a manual machine and what is halscope? linux dso? if so what do i need thanx Jon Elson did something with an automotive sensor. http://pico-systems.com/bridge_spindle.html Dave -- Systems Optimization Self Assessment Improve efficiency and utilization of IT resources. Drive out cost and improve service delivery. Take 5 minutes to use this Systems Optimization Self Assessment. http://www.accelacomm.com/jaw/sdnl/114/51450054/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Cloud Computing - Latest Buzzword or a Glimpse of the Future? This paper surveys cloud computing today: What are the benefits? Why are businesses embracing it? What are its payoffs and pitfalls? http://www.accelacomm.com/jaw/sdnl/114/51425149/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] [OT]elettromagnetic brakes
On Tuesday, December 13, 2011 07:52:30 PM Spiderdab did opine: Il giorno mar, 13/12/2011 alle 13.13 -0500, Dave ha scritto: On 12/13/2011 8:41 AM, Spiderdab wrote: Hi, and sorry for the ot question, but maybe your knowledge can help me. Do you know of someone selling cheap safety brakes, to be mounted on the back shaft of a stepper motor, with a torque of 570oz/in (about 4N/mt). I mean those when if current goes off they brake. Thank for any suggestion, Davide. Cheap and Safety don't normally go together. ;-) I know, but we are talking about a brake for 4N/mt, so it's a little torque.. What do you consider cheap? I'd like to find a less expensive holding brake for Nema 34 steppers, something in the $100 range would be nice. I found these. http://www.damencnc.com/en/components/motors-and-drivers/motor-add-ons /252 http://www.electroid.com/prod09.htm Dave first are very nice, but cost too much! 124€ for one brake! i've found something on rs site, that costs around 78€ per brake, but not with nema size mount. It has the same torque, 3,95N/mt http://it.rs-online.com/web/p/accessori-per-freni-frizioni/2677674/ about the second link, they don't put prices on the site, did you already asked for? I would, if building a ball screw machine, consider having an old gear on the drive, which could do double duty. It, with an adjacent magnet to the hall sensors (note plural for quadrature sensing), with a portion of the edge of one tooth laid back for a third hall device to furnish the index, serve as an encoder. But then just a bit more machining, and most any solenoid could be used to drive a parking pawl away from the gear where is was serving as a position lock when the solenoid's power is removed. Once the suitable gear was obtained mounted, and the hall effects stuff built, the addition of a solenoid to lock the gear is a very nominal cost, Perhaps 3 or 4 bucks from All Electronics and your time to make the pawl it controls. But my toys are stuck with steppers and acme bolts they lock in place very solidly. 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) My web page: http://coyoteden.dyndns-free.com:85/gene No animal should ever jump on the dining room furniture unless absolutely certain he can hold his own in conversation. -- Fran Lebowitz -- Cloud Computing - Latest Buzzword or a Glimpse of the Future? This paper surveys cloud computing today: What are the benefits? Why are businesses embracing it? What are its payoffs and pitfalls? http://www.accelacomm.com/jaw/sdnl/114/51425149/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Peter C. Wallace wrote: Theres a FAQ fom AMT that mentions a jumper on the card that can be removed to approximately 1/2 the filter time constant (at the expense of more noise) And, that is real hard to do once the hub has been glued! Oops! Jon -- Cloud Computing - Latest Buzzword or a Glimpse of the Future? This paper surveys cloud computing today: What are the benefits? Why are businesses embracing it? What are its payoffs and pitfalls? http://www.accelacomm.com/jaw/sdnl/114/51425149/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Tom Easterday wrote: On Dec 13, 2011, at 1:09 PM, Jon Elson wrote: If you can send me a picture form Halscope, I can compare it to what I get. See: http://bgp.nu/~tom/pub/XPosErr-VelCmd.png Doesn't look that bad. I'm a little surprised the FF2 can't make it better. But, then these systems with multiple smart controllers can be quite hard to tune. Jon -- Cloud Computing - Latest Buzzword or a Glimpse of the Future? This paper surveys cloud computing today: What are the benefits? Why are businesses embracing it? What are its payoffs and pitfalls? http://www.accelacomm.com/jaw/sdnl/114/51425149/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Tom Easterday wrote: These are versions without the velocity command at 250ipm and ~1500ipm Oh, at 1500 IPM, maybe you need to turn up the servo thread to faster than 1 ms, or have you tried that already? Jon -- Cloud Computing - Latest Buzzword or a Glimpse of the Future? This paper surveys cloud computing today: What are the benefits? Why are businesses embracing it? What are its payoffs and pitfalls? http://www.accelacomm.com/jaw/sdnl/114/51425149/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] newbee?
alice wrote: hey im jeremy been paying attention two this for several months now and am moving forward with my mill. was curious has any body experimented with gm crankshaft sensors? it seems that a tonwheel should be pretty easy even with a manual machine and what is halscope? linux dso? if so what do i need thanx I got some Avago Hall sensors from Digi-Key to build an encoder into the head of my Bridgeport. See http://pico-systems.com/bridge_spindle.html It works great for rigid tapping. Jon -- Cloud Computing - Latest Buzzword or a Glimpse of the Future? This paper surveys cloud computing today: What are the benefits? Why are businesses embracing it? What are its payoffs and pitfalls? http://www.accelacomm.com/jaw/sdnl/114/51425149/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
