Re: [Emc-users] Spindle Control
Gene When you say micromill are you referring to the X2. I have one of these as well. I am running it with EMC2 though the parallel port with a G540 driver. It accepts a VFD PWM signal and has an op-isolated 0 to 10 volt analog output for a VFD. It also has 2 uncommitted output pins. It looks like I could take the VFD PWM signals in parallel to feed the PMDX-106 or I may not need it if the VFD output will work for the mill motor controller. So how did you hook up the VSD to the PMDX. From a quick review of the PMDX-106 manual you can use the pot to set the speed through the PMDX but it uses an analog voltage out to set the VSD speed. You certainly seem to have put me on the right track. It looks like I need to break out the meter and read the values across the pot. It is starting to look like the G540 already almost everything I need except for the relays and signal conditioning for a sync signal. Reviewing the StepConf portion of the getting started guide makes me believe I have a chance for a first order solution in its spindle control section. Down stream I may want to achieve a more robust solution with something like the Mesa cards. Jon Warning noted. It looks like my driver may have already considered that and provides an optical isolated output and uses a PWM input. Thanks Hubert Gene Heskett wrote: On Friday 09 October 2009, Hubert Bahr wrote: Just some thinking out loud!! Is it possible to put a rotation detector on a spindle, use it as an input to EMC and then have EMC drive some type of digital to analog converter to change the speed until it agrees with the desired setting? Based on some past discussions on the list, I believe the answer to be yes. If so, what type of rotation detection is needed? What is the best way to convert the EMC output to be a control force for the spindle? I am talking about a spindle on the X3 Seig Mill. I am planning to convert the current gear drive to a two range belt drive, and since the current controller appears to use a pot to adjust the speed and a switch to change direction I believe I could use some type of control voltage and a relay to replace the pot and switch. I would appreciate any suggestions as I explore deeper. Hubert Hubert, I suspect, but don't know for sure, but PMDX makes a card called the PMDX-106, which with some booster relays, took the VSD card out of my micromill, put it in a box with the PMDX-106 and put it under emc control quite nicely. Now, the rest of the problem is probably a hal verse or 2 once the actual speed of the spindle is known to emc. There are folks here who can probably help with that part. As a side comment, the VSD from my micromill has very high gain, and without any feedback, I can hog the cut and blow the fuse without ever detecting a sag in the speed I hear. That got a bit tiresome and expensive for fuses, so my spindle motor now has a 150% jury rigged ammeter to show me how hard the motor is working. That makes me the relay element between keeping the motor working fairly hard, and the feed override slider to adjust it. It seems to me that could be linked, taking me out of the picture long enough to go make a fresh cup of tea. Based on that, you may want to see about using the feedback error to also modify the feed override slow the cut down to where the motor can handle it. Using a many turn toroid inductor, running one of the motor wires through it, rectify the output and a wee bit of smoothing filter, one could automate the feed override to always run as fast as the motor has the power to cut. This should approach the ideal cutter life too. Yeah, I dream a lot too, but this seems do-able to me. -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] parport_pc and the http://linuxcnc.org/experimental/hardy/smp/ kernels
Am 09.10.2009 um 22:34 schrieb Eric H. Johnson: Michael, How recently was that updated. I just did rebuilt of smp (2.3.3) earlier this week and have just not gotten around to posting them. the files in http://linuxcnc.org/experimental/hardy/smp/ are all 22- Apr-2009 if that's what you're referring to, emc is 2.3.0 in there could I pull the smp kernel debs from you? how? regards Michael -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Spindle Control
2009/10/10 Jon Elson el...@pico-systems.com: witch. Warning! The spindle speed controller on these machines is NOT isolated from the line. So, you need to provide some sort of isolation for and speed controller interface to the computer. PWM and optocouplers sounds like a good idea. When he says Not isolated he means 100V above ground, at least in the case of mine. Mine is a KBIC240D, the manual is here: http://www.kbelectronics.com/manuals/kbic_manual.pdf and it says that for external voltage control you need to supply a control voltage between P2 (normally the pot wiper) and F- (which is one of the motor terminals!) Fortunately there are small DC-DC converters that will produce a completely isolated 12V (or whatever) so it isn't as much of a problem as it sounds, just be careful with that control signal inside your control box and keep it away from other stuff. You probably need a PWM-voltage converter, preferably opto-isolated. I built a circuit which uses a precision current-source to charge a capacitor to control my drives and to operate FW/REV relays. http://imagebin.ca/view/FVZ50EL.html You would only need half of that, as I am controlling two spindles and choosing between them with binary logic. (You can quite probably improve on the circuit too) There is an article on closed-loop spindle speed control in the Wiki. http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Closed_Loop_Spindle_Speed_Control -- atp -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Spindle Control
Hubert, The term PWM as discussed here is referring to the signal from the parallel port to the device used to set the motor speed. In the case of the X2 and many other DC motor drivers, the current supply into the motor is also controlled by PWM, but it is generated and controlled by the motor driver speed control circuits, not directly by the parallel port. The gain that Gene referred to is the ability of the motor driver to regulate the motor speed under varying mechanical loads. The motor driver senses the motor back EMF while the PWM drive is turned off and uses that as a feedback signal representing the actual motor speed. There is a small pot within the drive to adjust the gain on this feedback and thus the stiffness of the speed regulation control loop. The G540 speed control output is isolated already. I am not sure if the X2 violates the 12 volt maximum control voltage imposed by the G540. The signals you need will be obtained by removing the wires from the pot in the X2 and connecting them as follows: Pos 7 VFD GROUND from X2 pot counterclockwise terminal Pos 8 VFD OUTPUT from X2 pot wiper terminal Pos 9 VFD +10VDC from X2 pot clockwise terminal You can check the X2 control voltage by measuring carefully across the pot with power applied. Remember that these signals are floating at line voltage!! You will also need to provide a relay to replace the switch on the back of the pot. The Output-1 and Output-2 terminals on the G540 can drive a suitable relay, but the relay will require a power source for its coil because the G540 provides only a transistor switch to ground. The X2 motor control is a little unusual. You cannot just switch the AC mains coming into it to start and stop the motor. The switch on the back of the pot must also cycle. Additionally, the motor driver should not be started at speed, it must be ramped up from zero or you will blow fuses. The ramping can be done with HAL. Lastly, if you require reversing, a large DPDT relay will be needed to swap the motor leads. This relay can be switched ONLY when the motor is fully stopped. Before you start rewiring, I recommend carefully documenting the connections inside your X2 motor control box. It is easy to assume that you can remember where the wires go, but then find that you had too many things going on and forget. Regards, Steve Stallings www.PMDX.com -Original Message- From: Hubert Bahr [mailto:h...@hbahr.org] Sent: Saturday, October 10, 2009 3:26 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Spindle Control Gene When you say micromill are you referring to the X2. I have one of these as well. I am running it with EMC2 though the parallel port with a G540 driver. It accepts a VFD PWM signal and has an op-isolated 0 to 10 volt analog output for a VFD. It also has 2 uncommitted output pins. It looks like I could take the VFD PWM signals in parallel to feed the PMDX-106 or I may not need it if the VFD output will work for the mill motor controller. So how did you hook up the VSD to the PMDX. From a quick review of the PMDX-106 manual you can use the pot to set the speed through the PMDX but it uses an analog voltage out to set the VSD speed. You certainly seem to have put me on the right track. It looks like I need to break out the meter and read the values across the pot. It is starting to look like the G540 already almost everything I need except for the relays and signal conditioning for a sync signal. Reviewing the StepConf portion of the getting started guide makes me believe I have a chance for a first order solution in its spindle control section. Down stream I may want to achieve a more robust solution with something like the Mesa cards. Jon Warning noted. It looks like my driver may have already considered that and provides an optical isolated output and uses a PWM input. Thanks Hubert -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] parport_pc and the http://linuxcnc.org/experimental/hardy/smp/ kernels
Michael, How recently was the parport fix added? Is it in 2.3.3? At any rate, I will send you the access information by private email. Regards, Eric the files in http://linuxcnc.org/experimental/hardy/smp/ are all 22- Apr-2009 if that's what you're referring to, emc is 2.3.0 in there could I pull the smp kernel debs from you? how? -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Spindle Control
On Saturday 10 October 2009, Jon Elson wrote: Hubert Bahr wrote: I am talking about a spindle on the X3 Seig Mill. I am planning to convert the current gear drive to a two range belt drive, and since the current controller appears to use a pot to adjust the speed and a switch to change direction I believe I could use some type of control voltage and a relay to replace the pot and switch. Warning! The spindle speed controller on these machines is NOT isolated from the line. So, you need to provide some sort of isolation for and speed controller interface to the computer. PWM and optocouplers sounds like a good idea. Jon The PMDX-106 takes care of that Jon, isolating all the VSD controller stuff. -- 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) The NRA is offering FREE Associate memberships to anyone who wants them. https://www.nrahq.org/nrabonus/accept-membership.asp All the people are so happy now, their heads are caving in. I'm glad they are a snowman with protective rubber skin -- They Might Be Giants -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Spindle Control
On Saturday 10 October 2009, Hubert Bahr wrote: Gene When you say micromill are you referring to the X2. I think the X2 is this ones bigger brother, selling for about $500, this was the $300 HF version. But I bought the expansion table kits from Chris at LittleMachineShop.com, and made a new z drive, pix at http://gene.homelinux.net:85/gene/emc I have one of these as well. I am running it with EMC2 though the parallel port with a G540 driver. It accepts a VFD PWM signal and has an op-isolated 0 to 10 volt analog output for a VFD. It also has 2 uncommitted output pins. It looks like I could take the VFD PWM signals in parallel to feed the PMDX-106 or I may not need it if the VFD output will work for the mill motor controller. So how did you hook up the VSD to the PMDX. Exactly as shown in the small manual it comes with. The electronic pot on the PMDX-106 replaces the manual pot entirely. But the PMDX-106 can be ordered with its own manual pot, which I got, so I have full manual control in addition to computer control. If push comes to shove, I could take it apart and draw up the hookup but that might be dangerous because the VSD in the X3 is probably a different model. I am one of those who hooks up one wire at a time and rarely draws a working schematic. I'd probably miss lay it a week later anyway. CRS etc. From a quick review of the PMDX-106 manual you can use the pot to set the speed through the PMDX but it uses an analog voltage out to set the VSD speed. You certainly seem to have put me on the right track. It looks like I need to break out the meter and read the values across the pot. A meter is _not_ a valid tool there as the voltage there is a very highly distorted AC. Hooking a scope up might be possible but the scope will have to be double insulated, like Phillips made them back in the late 70's. I just assumed that the homework had been done and followed directions as my 100mhz dual trace Hitachi is _not_ isolated, underwriters laboratories apparently having outlawed a very very useful feature. It is starting to look like the G540 already almost everything I need except for the relays and signal conditioning for a sync signal. Reviewing the StepConf portion of the getting started guide makes me believe I have a chance for a first order solution in its spindle control section. Down stream I may want to achieve a more robust solution with something like the Mesa cards. I used the teeny little relays on the PMDX-106 to run some socketed DPDT PB relays to do the actual high power switching, 2 of them IIRC. 1 for run/stop, and one wired in the classic x-crossover for direction reversal. A side effect of that which came in handy was that when the run relay was opened, I could use the backside contacts to throw a 10 ohm resistor across the motor coils, stopping it dead in about 2 or 3 revs from full speed. A dead short will do it even faster, but that can also demagnetize the motors field magnets, so 10 ohms was my compromise. I don't think I ever did draw a schematic of that part, but hooking up relays isn't rocket science. Also, do not reverse without letting it come to a full stop first, it will clear the fuse instantly if I forget that little detail. :( Jon Warning noted. It looks like my driver may have already considered that and provides an optical isolated output and uses a PWM input. As does the PMDX-106, needing a PWM input from a verse of hal code, and a reverse pin on the parport. Everything in the PMDX-106 depends on the presence of the PWM from the computer. [...] -- 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) The NRA is offering FREE Associate memberships to anyone who wants them. https://www.nrahq.org/nrabonus/accept-membership.asp Oregano, n.: The ancient Italian art of pizza folding. -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
A twisted pair, or any long piece of wire coming out of the back of a PC, is first and foremost, a transmission line, and needs to be terminated properly. This has nothing to do with the DC bias. The impedance of such a line is generally 50R to 75R. In the case of a printer port line, which is unbalanced, the line might have a 1k pullup, to satisfy DC conditions, but also needs a signal(AC) termination, usually a RC combination, and is often of low value, maybe a 100R and small capacitor. In the case of a proper balanced line, there is usually a single low value resistor (50R) across the line as it enters the differntial input of the amplifier, but thats not the case here. Trying to satisfy both AC and DC requirements with a single resistor, may either overload the port line if it is too low, or allow signal reflections if it too high. The line should be terminated with a pull-up according to the power output of the driver chip, then a scope used to select the correct RC combination. The RC connects the line to ground. Use a 100R resistor, and start with cap order of 50pF and increase it until you see a nice square wave. Roland 2009/10/9 Steve Blackmore st...@pilotltd.net On Thu, 08 Oct 2009 21:34:12 -0400, you wrote: If 120 ohms from the inputs to +5 is too much of a load, try 470 or 510 ohms. Any pull up action should work against the noise. If that's where the noise is attacking, some is better than none, and even 1K ohm might be enough to hold the noise at bay. Of course it's easy for me to talk, when I have a parts bin with assorted resistors handy. | Hi Jon - tried 120 Ohm across the inputs - it stopped the line receiver | working? The pull ups on the outputs helped marginally but it's much | better than it was and is quite usable. I'll order some better encoder | cable and will try and rewire. The 120 Ohm are not pull-ups, they are to balance the twisted pair. Steve Blackmore -- -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Spindle Control
Gene So you have the X-1, I have an X-2 and X-3 also from Habour Freight. I am guessing the principles are the same but I will need to check the implementation. Specifically, I am interested in what you connected to pins 1, 2 and 3 of PMDX-106's J2, the spindle signal connector. Specifically it states that pin 3 should not exceed 15 volts or you use either a +5 or +10 volt PMDX supplied reference. It looks like the G540 has similar capabilities but it is limited to 12 volts instead of 15. I am surprised you say that the voltage across the pot is ac, how could it be used a speed reference. I guess if you hooked it up as figure 7 it wouldn't matter. I could see it as being AC referenced to ground but not across the pot. But if necessary I can hook up my Tectronix purchased new in 1973 and use both channels in differential mode. I have also used them on a rubber mat with the 3rd power wire isolated and scope grounded to the target machine. I have also been known to blow the internal ground connection of the scope when I had both the 3rd wire connected and then grounded the scope to the other device. Experience has a way of providing very graphic examples of what not to do. What I need to do is measure the maximum voltage that would exist between pins 1 and 3 of the PMDX-106 or in my case VFD ground and VFD +10 lines of the G540. It has two outputs ready to drive relay coils sinking up to 1 amp from not over a 50 volt source. This should be sufficient to switch direction and power. The only need I anticipate for reversing spindle direction is for rigid tapping, I guess I need to study how that works in EMC2. Hubert -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Roland Jollivet wrote: A twisted pair, or any long piece of wire coming out of the back of a PC, is first and foremost, a transmission line, and needs to be terminated properly. This has nothing to do with the DC bias. The impedance of such a line is generally 50R to 75R. Actually, twised pairs usually come out to about 110 Ohms. The ratio of wire diameter to wire spacing changes it somewhat, but for normal signal wires just twisted together without additional spacer between, the differential impedance is almost always going to be between 100 and 120 Ohms. In the case of a proper balanced line, there is usually a single low value resistor (50R) across the line as it enters the differntial input of the amplifier, but thats not the case here. You will sometimes see a split termination, with two 50 Ohm resistors to ground or other voltage supply, the differential impedance would then be 100 Ohms. Trying to satisfy both AC and DC requirements with a single resistor, may either overload the port line if it is too low, or allow signal reflections if it too high. The line should be terminated with a pull-up according to the power output of the driver chip, then a scope used to select the correct RC combination. The RC connects the line to ground. Use a 100R resistor, and start with cap order of 50pF and increase it until you see a nice square wave. Yes, scoping the final result to make sure all the transient energy is completely absorbed is a good idea, if you are so equipped. Because of inductive and capacitive effects of all components, the ideal resistor value may not perform the best, and some adjustment to get the minimum ringing may be needed. Jon -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
2009/10/10 Jon Elson el...@pico-systems.com Roland Jollivet wrote: A twisted pair, or any long piece of wire coming out of the back of a PC, is first and foremost, a transmission line, and needs to be terminated properly. This has nothing to do with the DC bias. The impedance of such a line is generally 50R to 75R. Actually, twised pairs usually come out to about 110 Ohms. The ratio of wire diameter to wire spacing changes it somewhat, but for normal signal wires just twisted together without additional spacer between, the differential impedance is almost always going to be between 100 and 120 Ohms. Not quite. As you say below, with a balanced line one could terminate each line in a 50R to ground. This means that actually, each line is 50R, but they 'meet in the middle', and that's why one often uses a single, floating 100R. So, a balanced line is actually 2 x transmission lines, each of 50R, that terminate back to back. Yes, there are variances and peculiarities, but my gist is that a better understanding of what is happening is preferable to simply plugging components until something works or pops. Roland In the case of a proper balanced line, there is usually a single low value resistor (50R) across the line as it enters the differntial input of the amplifier, but thats not the case here. You will sometimes see a split termination, with two 50 Ohm resistors to ground or other voltage supply, the differential impedance would then be 100 Ohms. Trying to satisfy both AC and DC requirements with a single resistor, may either overload the port line if it is too low, or allow signal reflections if it too high. The line should be terminated with a pull-up according to the power output of the driver chip, then a scope used to select the correct RC combination. The RC connects the line to ground. Use a 100R resistor, and start with cap order of 50pF and increase it until you see a nice square wave. Yes, scoping the final result to make sure all the transient energy is completely absorbed is a good idea, if you are so equipped. Because of inductive and capacitive effects of all components, the ideal resistor value may not perform the best, and some adjustment to get the minimum ringing may be needed. Jon -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Encoders
Oops, yes. Thats what you said. Differential impedance = 100R Roland 2009/10/10 Roland Jollivet roland.jolli...@gmail.com 2009/10/10 Jon Elson el...@pico-systems.com Roland Jollivet wrote: A twisted pair, or any long piece of wire coming out of the back of a PC, is first and foremost, a transmission line, and needs to be terminated properly. This has nothing to do with the DC bias. The impedance of such a line is generally 50R to 75R. Actually, twised pairs usually come out to about 110 Ohms. The ratio of wire diameter to wire spacing changes it somewhat, but for normal signal wires just twisted together without additional spacer between, the differential impedance is almost always going to be between 100 and 120 Ohms. Not quite. As you say below, with a balanced line one could terminate each line in a 50R to ground. This means that actually, each line is 50R, but they 'meet in the middle', and that's why one often uses a single, floating 100R. So, a balanced line is actually 2 x transmission lines, each of 50R, that terminate back to back. Yes, there are variances and peculiarities, but my gist is that a better understanding of what is happening is preferable to simply plugging components until something works or pops. Roland In the case of a proper balanced line, there is usually a single low value resistor (50R) across the line as it enters the differntial input of the amplifier, but thats not the case here. You will sometimes see a split termination, with two 50 Ohm resistors to ground or other voltage supply, the differential impedance would then be 100 Ohms. Trying to satisfy both AC and DC requirements with a single resistor, may either overload the port line if it is too low, or allow signal reflections if it too high. The line should be terminated with a pull-up according to the power output of the driver chip, then a scope used to select the correct RC combination. The RC connects the line to ground. Use a 100R resistor, and start with cap order of 50pF and increase it until you see a nice square wave. Yes, scoping the final result to make sure all the transient energy is completely absorbed is a good idea, if you are so equipped. Because of inductive and capacitive effects of all components, the ideal resistor value may not perform the best, and some adjustment to get the minimum ringing may be needed. Jon -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Spindle Control
Hi Hubert, You need to be careful connecting to the pot inputs of a lot of these type of speed controllers. The usually put a DC voltage of anywhere between 7V to 15V across the potentiometer. The kicker is that this voltage is generated via a zener shunt regulator and the control voltage is actually 7V-15V below the mains voltage. You need to ensure that any pc control connection to this is isolated. I have a number of products including the DC-03 that take a pwm signal from the PC and convert this into an isolated dc control voltage that is suitable for controlling many types of DC motor controllers and VFDs. http://homanndesigns.com/store/index.php?main_page=product_infocPath=1products_id=21 As to the X3, I thought it used a brushless motor and the speed controller was digital with buttons for speed up/down and not suitable for accepting an analog control input that replaces a manual speed potentiometer. Cheers, Peter Hubert Bahr wrote: Just some thinking out loud!! Is it possible to put a rotation detector on a spindle, use it as an input to EMC and then have EMC drive some type of digital to analog converter to change the speed until it agrees with the desired setting? Based on some past discussions on the list, I believe the answer to be yes. If so, what type of rotation detection is needed? What is the best way to convert the EMC output to be a control force for the spindle? I am talking about a spindle on the X3 Seig Mill. I am planning to convert the current gear drive to a two range belt drive, and since the current controller appears to use a pot to adjust the speed and a switch to change direction I believe I could use some type of control voltage and a relay to replace the pot and switch. I would appreciate any suggestions as I explore deeper. Hubert -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.421 / Virus Database: 270.14.9/2426 - Release Date: 10/09/09 18:43:00 -- - eStore: http://www.homanndesigns.com/store Web : http://www.homanndesigns.com ModIO - Modbus Interface Unit email : pe...@homanndesigns.com DigiSpeed - Isolated 10Vdc I/F Phone : +61 421 601 665 TurboTaig - Taig Mill Upgrade board -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Spindle Control
Peter The SX3 or Super X3 sold by Grizzley (G0619) does use the digital control. The X3 sold by Harbor Freight and also Grizzley (G0463) use a speed potentiometer. My first attempt will be to use the VFD outputs of the Gecko G540 which provides an opto isolated pwm to analog reference. In its case it is limited to 12 volts so my first job is to determine the safest place to measure the voltage across the pot and then measure it. I was a radar technician in the mid 60's and then went back to get my BSE. So I am very leery of floating references. As you say these voltages may be anywhere from 7 to 15 volts. I can probably use the G540 pins as long as they are between 5 to 12 volts. I will post my findings. Physical inspection of the control boards in the two machines reveals different animals in types and quantity of components. Hopefully I will not have to reverse engineer them to get them to work. Hubert Peter Homann wrote: Hi Hubert, You need to be careful connecting to the pot inputs of a lot of these type of speed controllers. The usually put a DC voltage of anywhere between 7V to 15V across the potentiometer. The kicker is that this voltage is generated via a zener shunt regulator and the control voltage is actually 7V-15V below the mains voltage. You need to ensure that any pc control connection to this is isolated. I have a number of products including the DC-03 that take a pwm signal from the PC and convert this into an isolated dc control voltage that is suitable for controlling many types of DC motor controllers and VFDs. http://homanndesigns.com/store/index.php?main_page=product_infocPath=1products_id=21 As to the X3, I thought it used a brushless motor and the speed controller was digital with buttons for speed up/down and not suitable for accepting an analog control input that replaces a manual speed potentiometer. Cheers, Peter Hubert Bahr wrote: Just some thinking out loud!! Is it possible to put a rotation detector on a spindle, use it as an input to EMC and then have EMC drive some type of digital to analog converter to change the speed until it agrees with the desired setting? Based on some past discussions on the list, I believe the answer to be yes. If so, what type of rotation detection is needed? What is the best way to convert the EMC output to be a control force for the spindle? I am talking about a spindle on the X3 Seig Mill. I am planning to convert the current gear drive to a two range belt drive, and since the current controller appears to use a pot to adjust the speed and a switch to change direction I believe I could use some type of control voltage and a relay to replace the pot and switch. I would appreciate any suggestions as I explore deeper. Hubert -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.421 / Virus Database: 270.14.9/2426 - Release Date: 10/09/09 18:43:00 -- Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
