Re: [Emc-users] arc intersection question
You probably want to find the arc center first. This should help: http://www.google.com/search?hl=ensource=hpbiw=1920bih=934q=find+the+center+of+an+arc+from+two+pointsaq=faqi=g4g-m4aql=oq= The first reference isn't bad. Once you have the center, then it's easier to check around the circumference from arc start to arc stop and check for X or Y values past limits. Would that work for you? On 03/15/2011 02:40 AM, forget color wrote: this is more of a math question than an EMC question, but I need the question for EMC so thought someone else might have run into it. I'm trying to figure out how I can calculate whether an arc will go outside the working area of my CNC. Let's say I have an arc from the following parameters: x1,y1,x2,y2,radius,direction (CW or CCW) and that my working area boundaries are: minX = -5, minY = -5, maxX = 5, maxY = 5 how can i tell if the arc will go outside the boundaries? so, for example, an arc with these values would go outside the bounds: G0 x-4.5 y0 G02 x-4.5 y4 r2 in fact, it's almost entirely outside the bounds. but if I change the radius to 6, it won't. (or if I change the direction to ccw of course) thanks for any help!! -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] arc intersection question
Or, can you just let EMC check it for you? If you set the work envelope of your machine correctly, EMC will tell you if there are problems. Program exceeds machine limits Program exceed machine (max/min) on axis (X/Y/Z/A/B/C/U/V/W) [ Run Anyway ] [ Cancel ] And if you're using Axis it will show you any arcs that are outside of the work envelope. You can click on them and it will show what program line generated them. Would that help? On 03/15/2011 02:40 AM, forget color wrote: this is more of a math question than an EMC question, but I need the question for EMC so thought someone else might have run into it. I'm trying to figure out how I can calculate whether an arc will go outside the working area of my CNC. Let's say I have an arc from the following parameters: x1,y1,x2,y2,radius,direction (CW or CCW) and that my working area boundaries are: minX = -5, minY = -5, maxX = 5, maxY = 5 how can i tell if the arc will go outside the boundaries? so, for example, an arc with these values would go outside the bounds: G0 x-4.5 y0 G02 x-4.5 y4 r2 in fact, it's almost entirely outside the bounds. but if I change the radius to 6, it won't. (or if I change the direction to ccw of course) thanks for any help!! -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] arc intersection question
EMC only checks if the endpoints are outside the work envelope, not intermediary points on the arc. You can still load the program and look outside the bounds (if set up properly you see the extent of travel in the preview). Regards, Alex Or, can you just let EMC check it for you? If you set the work envelope of your machine correctly, EMC will tell you if there are problems. Program exceeds machine limits Program exceed machine (max/min) on axis (X/Y/Z/A/B/C/U/V/W) [ Run Anyway ] [ Cancel ] And if you're using Axis it will show you any arcs that are outside of the work envelope. You can click on them and it will show what program line generated them. Would that help? On 03/15/2011 02:40 AM, forget color wrote: this is more of a math question than an EMC question, but I need the question for EMC so thought someone else might have run into it. I'm trying to figure out how I can calculate whether an arc will go outside the working area of my CNC. Let's say I have an arc from the following parameters: x1,y1,x2,y2,radius,direction (CW or CCW) and that my working area boundaries are: minX = -5, minY = -5, maxX = 5, maxY = 5 how can i tell if the arc will go outside the boundaries? so, for example, an arc with these values would go outside the bounds: G0 x-4.5 y0 G02 x-4.5 y4 r2 in fact, it's almost entirely outside the bounds. but if I change the radius to 6, it won't. (or if I change the direction to ccw of course) thanks for any help!! -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Icon for pyVCP
On 03/14/2011 06:16 PM, Kirk Wallace wrote: On Mon, 2011-03-14 at 12:22 -0400, Mark Wendt wrote: On 03/14/2011 12:20 PM, Kirk Wallace wrote: On Mon, 2011-03-14 at 05:37 -0400, Mark Wendt wrote: ... snip Are you already starting it from a launcher on the desktop? ... snip Yes, I tried that a couple of times, but mostly I have been trying to get back to the terminal from the halcmd: prompt, which needs to happen first. Kirk, Can you post your startup script? Mark I have a shell script called config_modio that contains: cd /home/kwallace/emc2/homann/modio_config halrun -I h_modio_config.hal Make sure there's no CR/LF after the h_modio_config.hal. If that doesn't fix it, try exit with no quotes as your last line. I think you forgot the -f switch to call out the filename. I then created a launcher that calls the config_modio script. From the launcher, the pyVCP window comes up but the threads immediately stop and the keyboard locks up. I have to power off to reboot. If I invoke the script from a terminal, the pyVCP window works fine, but when I close the window, I am left with a halcmd: prompt, which I need to type exit to get back to the terminal prompt. Then just put exit with no quotes as your last line in the script. Do you really need the halcmd prompt to come up? If not, you can leave out the -I I tried a bare bones LED pyVCP window with my launcher and it doesn't lock up the keyboard, but it flashes the LED window and immediately exits back to the desktop. I think the latency test launcher does what I need to do, but it is fairly involved and will take some time to figure out how it works and then pick out the juicy bits. I also need to go through my modio_config component to see where things get locked up. I think I need to make it more fault tolerant, especially when it is trying to set up the serial port, but doesn't succeed. It seems the -I option gets ignored from the launcher, so the window pops up, but disappears while the serial port is getting setup. When I run the script from a terminal, the -I option gets honored and all is well, except I get returned to the halcmd: prompt because I'm in interactive or -I mode. Or that's my story so far. If you leave out the -I option, you won't get the halcmd prompt. Mark -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] higher speed spindle
On 15 March 2011 04:32, gene heskett ghesk...@wdtv.com wrote: I knocked that elderly BD apart tonight, far enough to see that it only needs the bearing on the chuck end of the shaft, but the collet is really a trashy collet, so if I follow that idea, I may as well start by making my own shaft to take a decent MT2 collet as I have those. Do what that chap Edward's link seems to have done, use an ER11 extension spindle as your basis: http://cgi.ebay.com/ER11-8MM-STRAIGHT-SHANK-CHUCK-CNC-MILLING-LATHE-D66-/150573752140 or 16mm dia, but needing a snap-ring groove or something http://cgi.ebay.com/New-C16-Er11-150L-Milling-Straight-Shank-Holder-US-/110452460881 ER11 goes up to 17/64. Then use the water pipe as you originally intended, with some $5 angular contact bearings to suit. (8mm and 20mm are easy, 16mm would need sleeving up or machining down, as there are no 16mm ID angular contact or taper-roller bearings. My hobbing axis uses the same idea, but with an ER32 holder and taper roller bearings. -- atp Torque wrenches are for the obedience of fools and the guidance of wise men -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Can G code subs RECURSIVELY call themselves?
(Googles) Hmm, Pretty. Interesting that most people square-up cubes on a mill, whereas even with a mill I prefer to do it with a lathe and a 4-jaw chuck (because of the 2-way square clamping) -- atp Torque wrenches are for the obedience of fools and the guidance of wise men -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] higher speed spindle
weight. HF also has a die grinder that might work too. I'll go look again. I use HF's Long Shaft Die Grinder for $24.99 (on sale with 20% off coupon). If you go this route, check the collet end as some can have along of play. I currently have 2 of these (for 1/4 and 1/8 collets). The collets on these are pretty cheap but serviceable. Brian -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] An interesting way to hold things together:
If you look at the last two pictures of this boring head: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItemitem=26077389 Wohlhaupter call it a differential screw. I assume this means that it has two different thread pitches, though it could mean that there are LH and RH sections. In either case it seems like a very compact way to join things, with no need for a bolt head seat. In fact, it can be assembled from below so you actually only need a big enough bore for the hex key in the top section. I will certainly be keeping it in mind for future situations where space is very tight. -- atp Torque wrenches are for the obedience of fools and the guidance of wise men -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] higher speed spindle
On Tuesday, March 15, 2011 09:49:41 AM andy pugh did opine: On 15 March 2011 04:32, gene heskett ghesk...@wdtv.com wrote: I knocked that elderly BD apart tonight, far enough to see that it only needs the bearing on the chuck end of the shaft, but the collet is really a trashy collet, so if I follow that idea, I may as well start by making my own shaft to take a decent MT2 collet as I have those. Do what that chap Edward's link seems to have done, use an ER11 extension spindle as your basis: http://cgi.ebay.com/ER11-8MM-STRAIGHT-SHANK-CHUCK-CNC-MILLING-LATHE-D66- /150573752140 or 16mm dia, but needing a snap-ring groove or something http://cgi.ebay.com/New-C16-Er11-150L-Milling-Straight-Shank-Holder-US-/ 110452460881 ER11 goes up to 17/64. Then use the water pipe as you originally intended, with some $5 angular contact bearings to suit. (8mm and 20mm are easy, 16mm would need sleeving up or machining down, as there are no 16mm ID angular contact or taper-roller bearings. My hobbing axis uses the same idea, but with an ER32 holder and taper roller bearings. Just to see if this idea is workable, and who knows, if a decent runtime life can be had, I bought one of those $30 Chicago Tools die grinders from HF last night. And for runtime extension, I have a speed controller I use with a PC router in my router table that could slow it down to just a few thou, still fast enough given what I seem to be able to do at 2500 revs in the mills own spindle, those mortises look sweet. Solid carbide router bits seem to be _very_ sharp, unlike the chip inlayed versions. Those absolutely must have the faces kissed and polished with a diamond wheel else they just burn their way through cherry. In the meantime while its on a truck, I can get the jig to hold the stick over the edge of the table made, and get an alu bar about 3 wide, an inch thick, and about 10 long sawed out and faced flat. I will drill tap the front of the spindle housing for about 4, 1/4 bolts so as to attach that to the face of the z sled, so it extends to the left about 8. Then when that grinder gets here so I can get some measurements off its extended nose, find some u-bolts drill for those. But because its a 30 dollar tool, expecting the nose piece to actually be in line with the shaft is probably asking too much, so I'll probably have to plow a groove to lay it in that might even be tapered from top to bottom. I have some .250 drill rod that might serve to extended the shaft line so I can measure the housings wibbles once the shaft is made true to the tables x axis. This should keep me out of the bars for a few days. ;-) -- 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) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html It is through symbols that man consciously or unconsciously lives, works and has his being. -- Thomas Carlyle -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] higher speed spindle
On Tuesday, March 15, 2011 10:27:07 AM andy pugh did opine: On 15 March 2011 04:32, gene heskett ghesk...@wdtv.com wrote: I knocked that elderly BD apart tonight, far enough to see that it only needs the bearing on the chuck end of the shaft, but the collet is really a trashy collet, so if I follow that idea, I may as well start by making my own shaft to take a decent MT2 collet as I have those. Do what that chap Edward's link seems to have done, use an ER11 extension spindle as your basis: http://cgi.ebay.com/ER11-8MM-STRAIGHT-SHANK-CHUCK-CNC-MILLING-LATHE-D66- /150573752140 or 16mm dia, but needing a snap-ring groove or something http://cgi.ebay.com/New-C16-Er11-150L-Milling-Straight-Shank-Holder-US-/ 110452460881 ER11 goes up to 17/64. That last doesn't look too bad, I'll look closer if this die grinder idea doesn't pan out. Decent precision for carving wood in ER11 collets doesn't look to cost that much either. Thanks Andy. Then use the water pipe as you originally intended, with some $5 angular contact bearings to suit. (8mm and 20mm are easy, 16mm would need sleeving up or machining down, as there are no 16mm ID angular contact or taper-roller bearings. My hobbing axis uses the same idea, but with an ER32 holder and taper roller bearings. For obviously heavier duty. OT question: In looking at milling machines in the grizzly catalog, I see some can rotate the tables as much as 45 degrees so that x motion is not perpendicular to y motion. Is this a thousand dollar feature that is actually useful, or just a sales gimmick? With cnc, that seems to be a non-feature to me because it can be done under gcode so much easier, and a return to square is always good because it was never actually moved. -- 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) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html We don't know who it was that discovered water, but we're pretty sure that it wasn't a fish. -- Marshall McLuhan -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] higher speed spindle
How did you go about mounting it to your rig, Brian? I mounted mine using three pieces of 3/4 MDF Two had a slot cut to fit the shaft of the spindle. I also put notches in the inner curve where the casting lines on the spindle would meet the slot. The third piece acts as a guillotine between the other two. It is slotted as well and I also drilled two holes through this third piece. I used all thread through these holes to a backing plate on the Z carraige. On the outboard side, I used washers and wingnuts to secure it. THis allows me to quickly take the unit off the machine with little fuss. I will take a picture this evening and email it to you. I doubt my powers of description will prove equal to a simple photo. I would avoid using the plastic motor case as a fixture point as the screws holding the motor to the spindle nose are less than substantial. I originally got the idea of using this grinder from this post almost 2 years ago. http://www.cnczone.com/forums/showthread.php?t=42227 Just eliminating the cooling air wash across the workpiece is worth the effort over a router. A small shop vac with this grinder will provide more than adequate dust collection for wood/MDF cutting. Brian -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Floating Oscilloscope
In order to investigate three phase issues more, it would be nice to measure at least two waves at a time. I have a two channel scope, but the channels are ground referenced. I can float the scope, but I think this will only allow me to measure one signal, or two if they happen to have the same reference point. Plus I don't think floating the scope is the safest practice for me or the scope. What might be good is to have a box that floats like a DVM but can feed a scope channel. What sort of keywords should I use to find such a thing, or is there a better way? -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tue, 15 Mar 2011, Kirk Wallace wrote: Date: Tue, 15 Mar 2011 11:16:18 -0700 From: Kirk Wallace kwall...@wallacecompany.com Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: [Emc-users] Floating Oscilloscope In order to investigate three phase issues more, it would be nice to measure at least two waves at a time. I have a two channel scope, but the channels are ground referenced. I can float the scope, but I think this will only allow me to measure one signal, or two if they happen to have the same reference point. Plus I don't think floating the scope is the safest practice for me or the scope. What might be good is to have a box that floats like a DVM but can feed a scope channel. What sort of keywords should I use to find such a thing, or is there a better way? -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA A couple isolation/stepdown transformers is a good way (I was going to say filament transformer but I guess not many would know what that is anymore) Peter Wallace Mesa Electronics -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
What about using a few mains9V transformers. Then you can common the secondaries. Sure, they'll all be phase shifted, but you should be able to see what's going on, and I think you'll see spikes or whatever in the waveform with a cutoff at about 400Hz. Regards Roland On 15 March 2011 20:16, Kirk Wallace kwall...@wallacecompany.com wrote: In order to investigate three phase issues more, it would be nice to measure at least two waves at a time. I have a two channel scope, but the channels are ground referenced. I can float the scope, but I think this will only allow me to measure one signal, or two if they happen to have the same reference point. Plus I don't think floating the scope is the safest practice for me or the scope. What might be good is to have a box that floats like a DVM but can feed a scope channel. What sort of keywords should I use to find such a thing, or is there a better way? -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Icon for pyVCP
On Tue, 2011-03-15 at 05:33 -0400, Mark Wendt wrote: ... snip I have a shell script called config_modio that contains: cd /home/kwallace/emc2/homann/modio_config halrun -I h_modio_config.hal Make sure there's no CR/LF after the h_modio_config.hal. If that doesn't fix it, try exit with no quotes as your last line. I think you forgot the -f switch to call out the filename. Thanks for your reply Mark. I don't think -f is an issue because the needed files get found and used. The -I is required in order to hold the terminal window or halrun open. The pyVCP application is spawned by the terminal or halrun so if it closes the app closes. The -I option tells halrun that while the app is running, I also want to interact with the app using halcmd on the terminal, which might include opening and closing other apps. So, when my app closes, the halcmd prompt remains because I told it to by using -I (?). I think the -I option is a bit of a cheat in this situation, and the real solution hasn't been created yet. Another option (-k for kill?) might be one that tells halrun to close if the app closes or find a way to have the app survive after the terminal closes. The latecy test app does this. I then created a launcher that calls the config_modio script. From the launcher, the pyVCP window comes up but the threads immediately stop and the keyboard locks up. I have to power off to reboot. If I invoke the script from a terminal, the pyVCP window works fine, but when I close the window, I am left with a halcmd: prompt, which I need to type exit to get back to the terminal prompt. Then just put exit with no quotes as your last line in the script. Do you really need the halcmd prompt to come up? If not, you can leave out the -I 'exit' had no effect because control isn't returned to the terminal command line until 'halrun' exits. For -I, see above. I tried a bare bones LED pyVCP window with my launcher and it doesn't lock up the keyboard, but it flashes the LED window and immediately exits back to the desktop. I think the latency test launcher does what I need to do, but it is fairly involved and will take some time to figure out how it works and then pick out the juicy bits. I also need to go through my modio_config component to see where things get locked up. I think I need to make it more fault tolerant, especially when it is trying to set up the serial port, but doesn't succeed. It seems the -I option gets ignored from the launcher, so the window pops up, but disappears while the serial port is getting setup. When I run the script from a terminal, the -I option gets honored and all is well, except I get returned to the halcmd: prompt because I'm in interactive or -I mode. Or that's my story so far. If you leave out the -I option, you won't get the halcmd prompt. See above. The 'emc' script does what I need too, but it is even more complex than the latecy test script. I suppose much could be learned from unlocking 'emc's secrets. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] unexpected realtime delay
Hi, Is there any way to adjust the sensitivity or suppress this error? I have an Atom D525 running the latest EMC2 from the repositories (Ubuntu 10.04). I have a Mesa 7I43 and Gecko 320 servo drives. I have no base thread at all, just the servo thread running at 700us. At 1ms I would get random 'thunks' from the servo only while jogging the X axis in the + direction at 120ipm. Minus X Jogs were smooth. After adjusting the servo thread to 700us all motors are super smooth no matter what. Just randomly getting this error - sometimes takes an hour to pop up. Like I said, the motors are running great so I don't really want to tweak the hyperthreading and isocpu= stuff. I don't understand why I'm getting this error with no base thread. Thanks, Joel Jacobs -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On 03/15/2011 11:18 AM, Peter C. Wallace wrote: On Tue, 15 Mar 2011, Kirk Wallace wrote: Date: Tue, 15 Mar 2011 11:16:18 -0700 From: Kirk Wallacekwall...@wallacecompany.com Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC)emc-users@lists.sourceforge.net Subject: [Emc-users] Floating Oscilloscope In order to investigate three phase issues more, it would be nice to measure at least two waves at a time. I have a two channel scope, but the channels are ground referenced. I can float the scope, but I think this will only allow me to measure one signal, or two if they happen to have the same reference point. Plus I don't think floating the scope is the safest practice for me or the scope. What might be good is to have a Tried that when troubleshot switching power supplies but it's not pleasant when you forget that the scope is on an isolated transformer especially in Europe with 220V. box that floats like a DVM but can feed a scope channel. What sort of keywords should I use to find such a thing, or is there a better way? current probe is one of the terms you could try. It's the current that eventually drives the motor not the voltage. Current probes are easy to use in such a measurement. They are easy to get these days but you could make one in your machine shop. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA A couple isolation/stepdown transformers is a good way (I was going to say filament transformer but I guess not many would know what that is anymore) yes we do. Peter Wallace Mesa Electronics -- Rafael -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] unexpected realtime delay
You can start with: 1) disabling the hyperthreading and 2) dedicating one of Atom's cores to EMC (and other RTAI functions) by adding isolcpus=1 to grub Unfortunately I cannot explain in more detail, how exactly to do it, so I can only advice asking uncle google. Viesturs 2011/3/15 Joel Jacobs j...@sdf.lonestar.org: Hi, Is there any way to adjust the sensitivity or suppress this error? I have an Atom D525 running the latest EMC2 from the repositories (Ubuntu 10.04). I have a Mesa 7I43 and Gecko 320 servo drives. I have no base thread at all, just the servo thread running at 700us. At 1ms I would get random 'thunks' from the servo only while jogging the X axis in the + direction at 120ipm. Minus X Jogs were smooth. After adjusting the servo thread to 700us all motors are super smooth no matter what. Just randomly getting this error - sometimes takes an hour to pop up. Like I said, the motors are running great so I don't really want to tweak the hyperthreading and isocpu= stuff. I don't understand why I'm getting this error with no base thread. Thanks, Joel Jacobs -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] unexpected realtime delay
On Tue, 15 Mar 2011, Joel Jacobs wrote: Date: Tue, 15 Mar 2011 15:22:04 -0400 From: Joel Jacobs j...@sdf.lonestar.org Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: emc-users@lists.sourceforge.net Subject: [Emc-users] unexpected realtime delay Hi, Is there any way to adjust the sensitivity or suppress this error? I have an Atom D525 running the latest EMC2 from the repositories (Ubuntu 10.04). I have a Mesa 7I43 and Gecko 320 servo drives. I have no base thread at all, just the servo thread running at 700us. At 1ms I would get random 'thunks' from the servo only while jogging the X axis in the + direction at 120ipm. Minus X Jogs were smooth. After adjusting the servo thread to 700us all motors are super smooth no matter what. Just randomly getting this error - sometimes takes an hour to pop up. Like I said, the motors are running great so I don't really want to tweak the hyperthreading and isocpu= stuff. I don't understand why I'm getting this error with no base thread. Thanks, Joel Jacobs You will still get unexpected realtime delay errors with just a servo thread if the latency gets to be more than 120% of the servo period (this would be 200 uSec at a 1ms servo thread period) This is a fairly serious amount of latency and probably should be looked into. I suspect your random thunks are also latency related. Possible fixes: Disable SMI Disable screensaver Make sure all power management is off in BIOS Disable monitor mode-set setting a reasonable value of stepgen maxaccel in the HAL/INI file will make the hardware stepgen more tolerant of latency -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ 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. -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Floating Oscilloscope
Look around in your junk box to see if you have any 120 ac to low voltage ac charging transformers for your battery powered drills, saws, garden clippers etc. The secondary voltage isn't an issue as you are looking at phase BUT.. make sure they are AC secondary of course. I have found that the wall warts usually outlast the batteries in the tools about 10 to one and since I never throw anything away I have a special box with dozens of them which get used for everything from plating/anodizing baths to actually charging batteries. I have been known to pick them up at garage sales if they cost less than a $.25. Worst case.. Radio shack sells 120/12 transformers in the neighborhood of $5 Cecil -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] How to access the SERVO_PERIOD from a component?
Thanks, I seen that functions that are put in a thread, have function(..., long period); as a argument. I'm taking this an it works if assumed that the given period is in seconds. Thanks for the clue, Javier On Mon, 2011-03-14 at 18:45 +, andy pugh wrote: On 14 March 2011 17:56, jros j...@unavarra.es wrote: I'm doing a component derivated from motenc that simulates a virtual machine. It would be nice If I could get the value of the SERVO PERIOD, If you are using comp, then you can use the variable fperiod. (which is the period in seconds in floating point format) -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Emc2 automake changes to get my own module compiled
Hi, I've finally have success implementing a Virtual machine, with 3 axes and a given dynamics. I've modified hal_motenc.c to that end. I would like to rename that file so that is compatible with the emc2 distro. How/Where should I change the compilation toolchain to get automagically my hal_motenc-virtual_machine_XYZ.c into a new module. Right now I'm placing the module in src/hal/drivers, but you can suggest a different location If you think it is more appropriate. I thin, once finished, the module, can be interesting to the community, how should I proceed to get the module into the distribution?. Thanks, Javier -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On 03/15/2011 12:16 PM, Kirk Wallace wrote: In order to investigate three phase issues more, it would be nice to measure at least two waves at a time. I have a two channel scope, but the channels are ground referenced. I can float the scope, but I think this will only allow me to measure one signal, or two if they happen to have the same reference point. Plus I don't think floating the scope is the safest practice for me or the scope. What might be good is to have a box that floats like a DVM but can feed a scope channel. What sort of keywords should I use to find such a thing, or is there a better way? You use a potential transformer. Find a pair of matched transformers, such as a 12 V output one, then you have a 10:1 reduction plus isolation on two totally independent voltages. Jon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] higher speed spindle
I forgott o mention. Check out Woodgears.ca for his tenoning jigs - lots of good stuff there. On Tue, Mar 15, 2011 at 1:32 PM, BRIAN GLACKIN glackin.br...@gmail.comwrote: How did you go about mounting it to your rig, Brian? I mounted mine using three pieces of 3/4 MDF Two had a slot cut to fit the shaft of the spindle. I also put notches in the inner curve where the casting lines on the spindle would meet the slot. The third piece acts as a guillotine between the other two. It is slotted as well and I also drilled two holes through this third piece. I used all thread through these holes to a backing plate on the Z carraige. On the outboard side, I used washers and wingnuts to secure it. THis allows me to quickly take the unit off the machine with little fuss. I will take a picture this evening and email it to you. I doubt my powers of description will prove equal to a simple photo. I would avoid using the plastic motor case as a fixture point as the screws holding the motor to the spindle nose are less than substantial. I originally got the idea of using this grinder from this post almost 2 years ago. http://www.cnczone.com/forums/showthread.php?t=42227 Just eliminating the cooling air wash across the workpiece is worth the effort over a router. A small shop vac with this grinder will provide more than adequate dust collection for wood/MDF cutting. Brian -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tue, 2011-03-15 at 11:18 -0700, Peter C. Wallace wrote: ... snip A couple isolation/stepdown transformers is a good way (I was going to say filament transformer but I guess not many would know what that is anymore) Peter Wallace Mesa Electronics Thanks Peter, Roland, Rafael, Jon. Judging by the number of replies, the question was too easy. Attached is my connection plan. The scope probe would go to the TP's. Would I be correct in thinking that the parallel connections shown, give me a voltage signal, and a series connection would give me current? -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA attachment: float_scope-1a.png-- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] arc intersection question
Kim's first answer is on the right track for me. I'm calculating all of the moves outside of EMC2 and passing them via emcrsh to Axis, one at a time. So I can't use the built-in viewer to know. Basically I need a formula that will tell me if the arc will go out of bounds given the things I already know (start,end,radius of arc and machine boundaries). thx On Tue, Mar 15, 2011 at 4:32 AM, Alex Joni alex.j...@robcon.ro wrote: EMC only checks if the endpoints are outside the work envelope, not intermediary points on the arc. You can still load the program and look outside the bounds (if set up properly you see the extent of travel in the preview). Regards, Alex Or, can you just let EMC check it for you? If you set the work envelope of your machine correctly, EMC will tell you if there are problems. Program exceeds machine limits Program exceed machine (max/min) on axis (X/Y/Z/A/B/C/U/V/W) [ Run Anyway ] [ Cancel ] And if you're using Axis it will show you any arcs that are outside of the work envelope. You can click on them and it will show what program line generated them. Would that help? On 03/15/2011 02:40 AM, forget color wrote: this is more of a math question than an EMC question, but I need the question for EMC so thought someone else might have run into it. I'm trying to figure out how I can calculate whether an arc will go outside the working area of my CNC. Let's say I have an arc from the following parameters: x1,y1,x2,y2,radius,direction (CW or CCW) and that my working area boundaries are: minX = -5, minY = -5, maxX = 5, maxY = 5 how can i tell if the arc will go outside the boundaries? so, for example, an arc with these values would go outside the bounds: G0 x-4.5 y0 G02 x-4.5 y4 r2 in fact, it's almost entirely outside the bounds. but if I change the radius to 6, it won't. (or if I change the direction to ccw of course) thanks for any help!! -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] axis plot loses chunks over time
I'm controlling axis via emcrsh. It is not uncommon for me to rack up hundreds of G1 moves (as well as many more G0) throughout a session. I have found that the live plot in Axis will occasionally lose chunks of what it has drawn, seemingly at random, but apparently only after it has been going for a while. Is this a known bug? I've seen it on Ubuntu as well as on Ubuntu running in VMWare Fusion on OS X. -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] axis plot loses chunks over time
On Tue, Mar 15, 2011 at 03:51:55PM -0500, forget color wrote: I'm controlling axis via emcrsh. It is not uncommon for me to rack up hundreds of G1 moves (as well as many more G0) throughout a session. I have found that the live plot in Axis will occasionally lose chunks of what it has drawn, seemingly at random, but apparently only after it has been going for a while. Yes, it's a feature. It discards the oldest parts of the backplot when it gets to be a certain size. Otherwise, the backplot would grow forever and the interactive response (note: not the realtime response) would get slower and slower. -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] unexpected realtime delay
Thanks for the suggestions! Running the latency test program seemed to top out around 15us which I was quite pleased with but never ran the test more than 10 min or so. I have bios power management and screen saver disabled. Just read about the SMI thing in the wiki and I would like to do some testing I guess but it said it could damage the CPU so I gotta ask, has there been any reports from the EMC community of damaged motherboards caused by disabling this? How about success stories? I came up empty searching for monitor mode-set what is that? Thanks much, Joel Jacobs -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tuesday, March 15, 2011 08:46:44 PM Kirk Wallace did opine: In order to investigate three phase issues more, it would be nice to measure at least two waves at a time. I have a two channel scope, but the channels are ground referenced. I can float the scope, but I think this will only allow me to measure one signal, or two if they happen to have the same reference point. Plus I don't think floating the scope is the safest practice for me or the scope. What might be good is to have a box that floats like a DVM but can feed a scope channel. What sort of keywords should I use to find such a thing, or is there a better way? That depends on the scope Kirk. 30 years ago the phrase 'double insulated' was all the rage, even for scopes. When I was the CE at KIVA-TV, I hit the station up for what I thought was a decent scope in view of all the stuff I was in charge of, so I bought a dual trace, 35 mhz rated, double insulated Phillips scope. That double insulated came in handier than a button on the outhouse door on several occasions, most noteworthy be the slipping of 3 layers of cambric and heat shrink, not shrunk, over the probe lead where the transmitter door closed on it, with the ground clip of the probe clipped onto the high side of a 10 ohm arc absorbing 100 watt resistor which was sitting at +1500 volts, and the probe clipped onto the other end of the resistor. This was the 4CX5000A visual driver stage, and I was suspecting that the sync compression I was seeing on the air was in that tube. The 4CX5000A is a shadow grid tube, meaning the screen grids wires are in the electrical shadow of the control grid. That also means they had damned well better stay there else the screen grid current will rise and that heats the wire until it gets hot enough to become an electron emitter. In this case I could see that the 40 mills and rapidly rising with the drive level current on the transmitters meters wasn't what I had come to expect as 5 to 10 mills would have been much closer to normal. That scope hooked up, allowed me to see it in real time, and disclosed that the peak current was actually around a full amp, for the duration of the sync pulse. Without it, I would have been guessing, but likely would have reached the same conclusion within a few days. So I tuned not for peak power, but for usable power, getting about 90% with much less compression than before, but that convinced me the tube was about fini. It took us a couple of weeks to collect enough money for a fresh one, and by the time it arrived it had faded to about 60%. KIVA-TV in Farmington NM, FWIW, was at that time only one step up from the smallest market in the country, Miles City MT. Starvation was always just around the corner. Back to the question: If your scope is blessed with this 'double insulated' moniker, then it would be _very_ illuminating to float the scope, then hook the ground to the otherwise unused center connection of the motor when it is wired as a Y, not delta. Hooked to the crotch of the Y, and the probes then connected to the other coils, you will be able to see in real time, the exact phase angles the motor is seeing. Needless to say, the scope is to be sitting on a dry wood table, and you are to be standing on a dry foam rubber foot cushion mat, wearing rubber soles. With one hand jammed deeply into a pocket... -- 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) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html If any man wishes to be humbled and mortified, let him become president of Harvard. -- Edward Holyoke -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tuesday, March 15, 2011 09:20:25 PM Roland Jollivet did opine: What about using a few mains9V transformers. Then you can common the secondaries. Sure, they'll all be phase shifted, but you should be able to see what's going on, and I think you'll see spikes or whatever in the waveform with a cutoff at about 400Hz. This also is a perfectly good idea Roland, but I doubt the 400HZ cutoff is all that sharp. And it certainly reduces the shock hazard to tolerable levels. Thanks. Now why didn't I think of that... -- 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) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html Congratulations are in order for Tom Reid. He says he just found out he is the winner of the 2021 Psychic of the Year award. -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tuesday, March 15, 2011 10:06:08 PM Kirk Wallace did opine: On Tue, 2011-03-15 at 11:18 -0700, Peter C. Wallace wrote: ... snip A couple isolation/stepdown transformers is a good way (I was going to say filament transformer but I guess not many would know what that is anymore) Peter Wallace Mesa Electronics Thanks Peter, Roland, Rafael, Jon. Judging by the number of replies, the question was too easy. Attached is my connection plan. The scope probe would go to the TP's. Would I be correct in thinking that the parallel connections shown, give me a voltage signal, and a series connection would give me current? For voltage and phases you are correct as shown. Currents however will need toroid type current transformers installed so the motor lead is threaded through the toroid core. You get a voltage out that is proportional to the current in the motor lead. -- 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) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html We is confronted with insurmountable opportunities. -- Walt Kelly, Pogo -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tue, 2011-03-15 at 21:23 -0400, gene heskett wrote: On Tuesday, March 15, 2011 09:20:25 PM Roland Jollivet did opine: What about using a few mains9V transformers. Then you can common the secondaries. Sure, they'll all be phase shifted, but you should be able to see what's going on, and I think you'll see spikes or whatever in the waveform with a cutoff at about 400Hz. This also is a perfectly good idea Roland, but I doubt the 400HZ cutoff is all that sharp. And it certainly reduces the shock hazard to tolerable levels. Thanks. Now why didn't I think of that... I almost ready: http://www.supplylinedirect.com/UserFiles/Image/Arc_flash_suit_on_model_narrow.jpg but will the wallwart primaries take 240V? If not, I could put two in series, but I would then need two pair that match so the signals would be comparable for each scope channel? -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tue, 2011-03-15 at 22:08 -0400, gene heskett wrote: On Tuesday, March 15, 2011 10:06:08 PM Kirk Wallace did opine: On Tue, 2011-03-15 at 11:18 -0700, Peter C. Wallace wrote: ... snip A couple isolation/stepdown transformers is a good way (I was going to say filament transformer but I guess not many would know what that is anymore) Peter Wallace Mesa Electronics Thanks Peter, Roland, Rafael, Jon. Judging by the number of replies, the question was too easy. Attached is my connection plan. The scope probe would go to the TP's. Would I be correct in thinking that the parallel connections shown, give me a voltage signal, and a series connection would give me current? For voltage and phases you are correct as shown. Currents however will need toroid type current transformers installed so the motor lead is threaded through the toroid core. You get a voltage out that is proportional to the current in the motor lead. Dooh (hits forehead). A transformer in series with a motor lead would be a bad idea (unless designed to be there). Small toroidal's are easy and plentiful, but another time sink. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating Oscilloscope
On Tuesday, March 15, 2011 11:29:43 PM Kirk Wallace did opine: On Tue, 2011-03-15 at 21:23 -0400, gene heskett wrote: On Tuesday, March 15, 2011 09:20:25 PM Roland Jollivet did opine: What about using a few mains9V transformers. Then you can common the secondaries. Sure, they'll all be phase shifted, but you should be able to see what's going on, and I think you'll see spikes or whatever in the waveform with a cutoff at about 400Hz. This also is a perfectly good idea Roland, but I doubt the 400HZ cutoff is all that sharp. And it certainly reduces the shock hazard to tolerable levels. Thanks. Now why didn't I think of that... I almost ready: http://www.supplylinedirect.com/UserFiles/Image/Arc_flash_suit_on_model_ narrow.jpg VBG... Nomex underwear too? ;) but will the wallwart primaries take 240V? If not, I could put two in series, but I would then need two pair that match so the signals would be comparable for each scope channel? I don't believe I'd try then on the 240. The iron would likely saturate, leading to smoke unpleasant odors. Say in 2 or 3 minutes... -- 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) http://tinyurl.com/ddg5bz http://www.cantrip.org/gatto.html They're unfriendly, which is fortunate, really. They'd be difficult to like. -- Avon -- Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
