[Emc-users] PLC for special purpose CNC
Hi, May i ask a question, what's the common status about specialized PLC that supports high performance languages like C/C++, does this have any advantage in the CNC and special machines design and manufacturing or not worth the price. What's the most common approach to control systems (boards, plc ...) when designing a complex cnc machine. Thanks & reagards Jean-François ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] PLC for special purpose CNC
Andy Sam, thanks for highlights Jean-François On 8/15/23 15:20, Sam Sokolik wrote: Well... Linuxcnc has a integrated ladder logic. (classic ladder). You also have the ability to write realtime components in C like language. http://linuxcnc.org/docs/stable/html/hal/comp.html I have retrofitted a cnc with 96 i/o and all is controlled with linuxcnc. (both ladder and C) sam On Tue, Aug 15, 2023 at 8:08 AM Jean-François Simon wrote: Hi, May i ask a question, what's the common status about specialized PLC that supports high performance languages like C/C++, does this have any advantage in the CNC and special machines design and manufacturing or not worth the price. What's the most common approach to control systems (boards, plc ...) when designing a complex cnc machine. Thanks & reagards Jean-François ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Question to electrics gurus: Correct setup for rectifier + capacitor
Hi good morning, I never eared of a power rectifier directly connected to the line, usually there will be like slow charge circuit through resistors, often also a filter at input stage, like LCL with inductors. Based on the explanations, i can't figure the details, is it so you design and built a custom circuit, or implemented existed modified circuits ? Essentially, yes it depends on the power rating, and passed a point, drives have both charge and discharge circuits, as you can't feed up instantly, it would exceed some ratings. The parts damaged at fast charge i guess would be also the diode bridge, some wire and connections, for capacitors i'm not sure they would be at issue, though they can overheat from the internal resistance. If i got it right, you are trying assemble modules (like a rectifier bridge with other things, DC bus and inverters), then we need to look at the module datasheet and ratings to fogure out these things. It's quite wrong Caps remain charge, that should never happen, all drives discharge the internal caps at standstill, something's failed or missing. Regards Jean-François On 8/6/24 22:44, Viesturs Lācis wrote: Hello! Recently I have posted some questions about the retrofit that I am working on and now I have encountered an issue that I cannot figure out. The thing is that I am swapping original Yaskawa servo drives with Mesa 8i20. One of the things for that was 3phase rectifier bridge (it takes 230 VAC input and provides 340V output) and 4700 uF capacitor for smoothing the ripple. It took me some time and some patience from PCW to fix the config and in the end I got one 8i20 to move one joint in the machine. So my next step was adding 2 more 8i20 drives for remaining 2 joints. It ended up with a blast in one 8i20. So I replaced it as well as I had to replace rectifier bridge. But now my issue is that protection fuse is tripped as soon as I enable machine power. 1) only rectifier bridge connected - all good 2) rectifier bridge + capacitor - fuse tripped immediately Note that I have not yet connected DC bus to 8i20 drives. I checked capacitor with multimeter, it was showing 180V DC (and it did not decrease in that time that I was holding multemeters pins there). I am not sure if that is some residual charge from previous (which I doubt) or if that was some charge that was acquired before fuse was tripped, but this seems to me like a good capacitor. Is that correct? I do not understand why was everything fine in initial testing - I did turn machine on and off lots of times and capacitor was discharged (and recharged!!!) numerous times. I have swapped that fuse for identical unit from a machine that has yet to go through the retrofit process. And it is the same. So my question to electronics gurus - could capacitor be damaged or was it just a beginners luck that everything worked and do I need to introduce some inductor between rectifier bridge and capacitor to limit the startup current that charges capacitor? Viesturs ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Question to electrics gurus: Correct setup for rectifier + capacitor
Got it then you need a proper DC bus with charge circuit if it gets some good power, and safety discharge, you never want charged caps in some place around, at this high Voltage. Question do you build the rectifier, do you get it from something existing ? Basically yes, you need slow charge to not blow something provided the load behind is great enough to need it, otherwise you'll get as you do, blown fuse or damage something else, that depends on inrush current. I and others can perhaps provide a couple hints, depends on what you are really going to design, ie from bulks or custom. Regards Jean-François On 8/7/24 09:45, Viesturs Lācis wrote: Hello Jean-François! I am using Mesa 8i20 servo drives that do not have built-in power supply, it takes DC as power input so I am trying to figure out how to do that properly. It seems to me that only a pair of rectifier bridge and capacitor is not enough to keep fuses happy. I do not worry about discharging the capacitor - what I observed from initial testing with one 8i20, it seems to me that drive does slowly discharge it - voltage dropped to few volts within a minute or so. Peter, is that intended or was it just some kind of happy moment and I actually should worry about discharge circuit as well? Viesturs trešd., 2024. g. 7. aug., plkst. 10:19 — lietotājs Jean-François Simon () rakstīja: Hi good morning, I never eared of a power rectifier directly connected to the line, usually there will be like slow charge circuit through resistors, often also a filter at input stage, like LCL with inductors. Based on the explanations, i can't figure the details, is it so you design and built a custom circuit, or implemented existed modified circuits ? Essentially, yes it depends on the power rating, and passed a point, drives have both charge and discharge circuits, as you can't feed up instantly, it would exceed some ratings. The parts damaged at fast charge i guess would be also the diode bridge, some wire and connections, for capacitors i'm not sure they would be at issue, though they can overheat from the internal resistance. If i got it right, you are trying assemble modules (like a rectifier bridge with other things, DC bus and inverters), then we need to look at the module datasheet and ratings to fogure out these things. It's quite wrong Caps remain charge, that should never happen, all drives discharge the internal caps at standstill, something's failed or missing. Regards Jean-François On 8/6/24 22:44, Viesturs Lācis wrote: Hello! Recently I have posted some questions about the retrofit that I am working on and now I have encountered an issue that I cannot figure out. The thing is that I am swapping original Yaskawa servo drives with Mesa 8i20. One of the things for that was 3phase rectifier bridge (it takes 230 VAC input and provides 340V output) and 4700 uF capacitor for smoothing the ripple. It took me some time and some patience from PCW to fix the config and in the end I got one 8i20 to move one joint in the machine. So my next step was adding 2 more 8i20 drives for remaining 2 joints. It ended up with a blast in one 8i20. So I replaced it as well as I had to replace rectifier bridge. But now my issue is that protection fuse is tripped as soon as I enable machine power. 1) only rectifier bridge connected - all good 2) rectifier bridge + capacitor - fuse tripped immediately Note that I have not yet connected DC bus to 8i20 drives. I checked capacitor with multimeter, it was showing 180V DC (and it did not decrease in that time that I was holding multemeters pins there). I am not sure if that is some residual charge from previous (which I doubt) or if that was some charge that was acquired before fuse was tripped, but this seems to me like a good capacitor. Is that correct? I do not understand why was everything fine in initial testing - I did turn machine on and off lots of times and capacitor was discharged (and recharged!!!) numerous times. I have swapped that fuse for identical unit from a machine that has yet to go through the retrofit process. And it is the same. So my question to electronics gurus - could capacitor be damaged or was it just a beginners luck that everything worked and do I need to introduce some inductor between rectifier bridge and capacitor to limit the startup current that charges capacitor? Viesturs ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https
Re: [Emc-users] Question to electrics gurus: Correct setup forrectifier + capacitor
Hi Gene, Not my project, i was answering to someone else. I confirm it has to be properly designed and certified, best to use certified apparatus in an electrical box. Generally i would stick to 48Vdc as far as practical. Above that, a properly constructed box with E-off with certified parts shouldn't cost a lot and is required. If unfamiliar, the original author should seek specialized support to build it safely & properly, for sure. Regards Jean-François On 8/7/24 13:53, gene heskett wrote: On 8/7/24 03:17, Jean-François Simon wrote: Hi good morning, I never eared of a power rectifier directly connected to the line, usually there will be like slow charge circuit through resistors, often also a filter at input stage, like LCL with inductors. Based on the explanations, i can't figure the details, is it so you design and built a custom circuit, Yes, so can you. Easier for me as I am a Certified Electronics Tech. This stuff is potentially lethal to the unwary. or implemented existed modified circuits ? actually probably invented long before me. Essentially, yes it depends on the power rating, and passed a point, drives have both charge and discharge circuits, as you can't feed up instantly, it would exceed some ratings. The parts damaged at fast charge i guess would be also the diode bridge, some wire and connections, for capacitors i'm not sure they would be at issue, though they can overheat from the internal resistance. Any cap that heats when used within its ratings is junk, replace it with good ones. If i got it right, you are trying assemble modules (like a rectifier bridge with other things, DC bus and inverters), then we need to look at the module datasheet and ratings to fogure out these things. Basically yes, but bear in mind this is dangerous stuff that only needs one wrong move to make your wife a widow. Logic level voltages cannot usually be felt, line level voltages are a different critter that can kill. If you aren't comfy with it, get and pay someone knowledgeable who is. It's quite wrong Caps remain charge, that should never happen, all drives discharge the internal caps at standstill, something's failed or missing. All quality drives generally will, but do not trust them. A good capacitor, charged when disconnected can knock you against a wall a year later. 20 microamps directly thru the heart can cause it to loose timing, fibrillate and kill. You may not even feel it. 20 milliamps you will feel but it will also freeze it, and if someone manages to disconnect you fast enough, the heart will often start back up and you will survive, but such a shock will often trigger a 6 month bout with shingles. In my experience as a broadcast engineer, BTDT, not the least bit pleasant, but I'm still here as I look at my 90th. If I come off as brutal, I'm trying to save you. Take care and stay alive. Regards Jean-François On 8/6/24 22:44, Viesturs Lācis wrote: Hello! Recently I have posted some questions about the retrofit that I am working on and now I have encountered an issue that I cannot figure out. The thing is that I am swapping original Yaskawa servo drives with Mesa 8i20. One of the things for that was 3phase rectifier bridge (it takes 230 VAC input and provides 340V output) and 4700 uF capacitor for smoothing the ripple. It took me some time and some patience from PCW to fix the config and in the end I got one 8i20 to move one joint in the machine. So my next step was adding 2 more 8i20 drives for remaining 2 joints. It ended up with a blast in one 8i20. So I replaced it as well as I had to replace rectifier bridge. But now my issue is that protection fuse is tripped as soon as I enable machine power. 1) only rectifier bridge connected - all good 2) rectifier bridge + capacitor - fuse tripped immediately Note that I have not yet connected DC bus to 8i20 drives. I checked capacitor with multimeter, it was showing 180V DC (and it did not decrease in that time that I was holding multemeters pins there). I am not sure if that is some residual charge from previous (which I doubt) or if that was some charge that was acquired before fuse was tripped, but this seems to me like a good capacitor. Is that correct? I do not understand why was everything fine in initial testing - I did turn machine on and off lots of times and capacitor was discharged (and recharged!!!) numerous times. I have swapped that fuse for identical unit from a machine that has yet to go through the retrofit process. And it is the same. So my question to electronics gurus - could capacitor be damaged or was it just a beginners luck that everything worked and do I need to introduce some inductor between rectifier bridge and capacitor to limit the startup current that charges capacitor? Viesturs ___ Emc-users mailing list Emc-users@lists.sourceforge.net https
