Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi Philipp, thanks for the summery. I'd be interested in hearing what solution you come up (if any) in the end. Maybe you could post this briefly once the project is finished. The problem seams to be common. there is no space left for one or two PHYs and the Ethernet jack(s). The jacks have a rather large footprint indeed, the PHY can be pretty small, I'm sue I've seen packages smaller than 5x5 mm. Regarding the RJ45 connectors you could replace them by something smaller (e.g. Molex Mini50), just like lot of the Ultrabook manufacturers do, but that would spoil a lot of the advantages of Ethernet. See you Flo -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
I am already using the 7i80 code on Micro controller although currently only running on desktop with servo motor from real machine. Nicklas Karlsson On Mon, 8 Jun 2015 17:07:36 + Ralph Stirling ralph.stirl...@wallawalla.edu wrote: Philipp, You should look at the ethernet-based system Peter Wallace created for the Mesa cards. The FPGA firmware and drivers for the Mesa system is open source. The 7I92 or 7I80DB should have some code examples you can look at. -- Ralph From: Philipp Burch [p...@hb9etc.ch] Sent: Monday, June 08, 2015 9:06 AM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box] Hi Dave! On 08.06.2015 15:43, Dave Cole wrote: ___ From the Ethercat Technology Group membership application page: The membership cost is pretty low... !!! :-) And there are some sample Ethercat master and slave source code available http://www.ethercat.org/en/products/4F84049B9950437FB34749A52AB20786.htm http://www.ethercat.org/en/products/54FA3235E29643BC805BDD807DF199DE.htm There is also at least one Ethercat open source master repository out there.. http://sourceforge.net/projects/soem.berlios/ Dave Good to know that it's free of charge. But since I'm mainly interested in the slave part, things are not that easy: Their slave sample code is for a microncontroller interfacing the EtherCAT-ASIC, so they're just making their money somewhere else ;) Thanks, Philipp -- ___ 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] Serial FPGA buses/interconnections [Was: Sandy box]
Hi Andy! On 08.06.2015 20:45, andy pugh wrote: On 8 June 2015 at 18:46, Dave Cole linuxcncro...@gmail.com wrote: make up your own basic protocols to move data between devices, but that can quickly turn into a wheel reinvention project on its own. I wonder if the Mesa Smart Serial protocol would work? Maybe, I'll have to look into it. Maybe PCW could justify if that would be a good idea or not ;) Cheers, Philipp signature.asc Description: OpenPGP digital signature -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi Rafael, hi everyone! On 09.06.2015 03:23, Rafael wrote: While waiting for experts to respond I did some research on this interesting topics ... ... Nothing wrong with being proprietary if nothing else out there suits your needs. However, when it comes to communications between logical devices you have to pay the price. Either you need to increase complexity for more reliable connections or use simpler protocols for lower HW costs. Ethernet interface chips are low cost these days, many hobby SBCs come with it. Benefits in using them is in their power to handle the TCP/IP connection without more than dumping bytes in and out of it's registers something most microcontrollers can easily do these days. This complexity vs. reliability stuff may be a bit misleading when it comes to hard-realtime systems. TCP is obviously a very reliable protocol if it is sufficient if the data just arrives sometimes. But especially for a control loop, waiting for milliseconds just because a frame has been lost would most likely cause much more harm than to just forget about it. But since I only need to link boards together which are no more than, say, at most 5m apart (most likely they will be directly adjacent, maybe 20cm of cable inbetween), any sensibly designed hardware interface is unlikely to cause any significant loss of data at all. BER maybe 10^(-12) or even much lower. Should there be considerable data corruption for some reason, then a better approach for a fast hard-realtime system would be to use some forward error correction (Hamming, Reed-Solomon, Convolution, whatever), because requesting a corrupted frame again will always fail for cycle times below 10ms or something like that. ... Rough requirements would be: - Usable for daisy-chaining (no common bus) Wouldn't failure in any single link bring everything down? Fibre channel Arbitrated loop (FC-AL) and Tokenring work fall in that category. Each host has to pass the message along the line so there is a delay between the first and last host. Sure, one broken link will bring the interface down (or at least part of it, the loop could be closed by the device just before the point of failure). But: The interface will be used to link a master to some motion and I/O controllers. If one of these devices or a link fails, the machine has to be shut down anyway, as there would be no point to run it with only half of the axes functional. Concerning the transmission delays: Since all those devices have the interface right in an FPGA, the delay imposed by each slave can be very short, even below the time for a single bit. - Data rate somewhere in the range 1Mbps .. 10Mbps - Serial with exactly one RX and one TX pair in each link What's the max distance between the hosts? What are electrical characteristics for connections between the hosts? There are other considerations that need to be looked at: how many units are connected in the chain? How do you implement the communication part? Microprocessor? ASIC? Do you need isolation between them? See above: Distances are short, 5m are already a rather high guess. A simple differential interface will do, all devices can share a common ground, but at least some noise immunity should be provided (hence differential signaling). A chain will consist of sometimes only two and sometimes up to, say, ten devices. The interface is implemented in an FPGA. CAT-6 cabling would likely fit the job as far as physical connections and relative distance go. Low cost, easy to connect to hubs or switches. Advantage of ethernet is in possibility to wrap any protocol into TCP/IP and route it elsewhere. Not deterministic of course but possibly good enough for remote troubleshooting or monitoring. On the other hand, nobody prevents you to write your own version of network protocol. UDP came to mind first but because it's not reliable I did additional research and found Reliable User Datagram Protocol https://en.wikipedia.org/wiki/Reliable_User_Datagram_Protocol It's not a formal standard or widely used but the description is available https://tools.ietf.org/html/draft-ietf-sigtran-reliable-udp-00 It seems very simple to me so it would not be too hard to write a driver I think. I already have a system running which uses a UDP connection between LinuxCNC and a controller. This works quite well. But this is the only real Ethernet connection in this system, it is simply overkill for the connections between every two boards. - Suitable for deterministic cyclic transfers with some tens of bytes each Not sure how you can do that without a dedicated clock line. I'm not talking about determinism in the sub-nanosecond range and everything above is not that difficult to realize with an almost direct connection between multiple FPGAs. If I transmit 10 Bytes at 1Mbps, this will always take exactly 80us on the wire (plus-minus some jitter, yes, yes). Let me just
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
TCP need acknowledge but for periodic data this may be skipped. For periodic data I use to add a timeout at receiver instead of acknowledge. Hi Rafael, hi everyone! On 09.06.2015 03:23, Rafael wrote: While waiting for experts to respond I did some research on this interesting topics ... ... Nothing wrong with being proprietary if nothing else out there suits your needs. However, when it comes to communications between logical devices you have to pay the price. Either you need to increase complexity for more reliable connections or use simpler protocols for lower HW costs. Ethernet interface chips are low cost these days, many hobby SBCs come with it. Benefits in using them is in their power to handle the TCP/IP connection without more than dumping bytes in and out of it's registers something most microcontrollers can easily do these days. This complexity vs. reliability stuff may be a bit misleading when it comes to hard-realtime systems. TCP is obviously a very reliable protocol if it is sufficient if the data just arrives sometimes. But especially for a control loop, waiting for milliseconds just because a frame has been lost would most likely cause much more harm than to just forget about it. But since I only need to link boards together which are no more than, say, at most 5m apart (most likely they will be directly adjacent, maybe 20cm of cable inbetween), any sensibly designed hardware interface is unlikely to cause any significant loss of data at all. BER maybe 10^(-12) or even much lower. Should there be considerable data corruption for some reason, then a better approach for a fast hard-realtime system would be to use some forward error correction (Hamming, Reed-Solomon, Convolution, whatever), because requesting a corrupted frame again will always fail for cycle times below 10ms or something like that. ... Rough requirements would be: - Usable for daisy-chaining (no common bus) Wouldn't failure in any single link bring everything down? Fibre channel Arbitrated loop (FC-AL) and Tokenring work fall in that category. Each host has to pass the message along the line so there is a delay between the first and last host. Sure, one broken link will bring the interface down (or at least part of it, the loop could be closed by the device just before the point of failure). But: The interface will be used to link a master to some motion and I/O controllers. If one of these devices or a link fails, the machine has to be shut down anyway, as there would be no point to run it with only half of the axes functional. Concerning the transmission delays: Since all those devices have the interface right in an FPGA, the delay imposed by each slave can be very short, even below the time for a single bit. - Data rate somewhere in the range 1Mbps .. 10Mbps - Serial with exactly one RX and one TX pair in each link What's the max distance between the hosts? What are electrical characteristics for connections between the hosts? There are other considerations that need to be looked at: how many units are connected in the chain? How do you implement the communication part? Microprocessor? ASIC? Do you need isolation between them? See above: Distances are short, 5m are already a rather high guess. A simple differential interface will do, all devices can share a common ground, but at least some noise immunity should be provided (hence differential signaling). A chain will consist of sometimes only two and sometimes up to, say, ten devices. The interface is implemented in an FPGA. CAT-6 cabling would likely fit the job as far as physical connections and relative distance go. Low cost, easy to connect to hubs or switches. Advantage of ethernet is in possibility to wrap any protocol into TCP/IP and route it elsewhere. Not deterministic of course but possibly good enough for remote troubleshooting or monitoring. On the other hand, nobody prevents you to write your own version of network protocol. UDP came to mind first but because it's not reliable I did additional research and found Reliable User Datagram Protocol https://en.wikipedia.org/wiki/Reliable_User_Datagram_Protocol It's not a formal standard or widely used but the description is available https://tools.ietf.org/html/draft-ietf-sigtran-reliable-udp-00 It seems very simple to me so it would not be too hard to write a driver I think. I already have a system running which uses a UDP connection between LinuxCNC and a controller. This works quite well. But this is the only real Ethernet connection in this system, it is simply overkill for the connections between every two boards. - Suitable for deterministic cyclic transfers with some tens of bytes each Not sure how you can do that without a dedicated clock line. I'm not talking about determinism in the sub-nanosecond range and everything above is not that difficult to realize with an almost direct connection between
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
On 6/8/2015 12:06 PM, Philipp Burch wrote: Hi Dave! On 08.06.2015 15:43, Dave Cole wrote: ___ From the Ethercat Technology Group membership application page: The membership cost is pretty low... !!! :-) And there are some sample Ethercat master and slave source code available http://www.ethercat.org/en/products/4F84049B9950437FB34749A52AB20786.htm http://www.ethercat.org/en/products/54FA3235E29643BC805BDD807DF199DE.htm There is also at least one Ethercat open source master repository out there.. http://sourceforge.net/projects/soem.berlios/ Dave Good to know that it's free of charge. But since I'm mainly interested in the slave part, things are not that easy: Their slave sample code is for a microncontroller interfacing the EtherCAT-ASIC, so they're just making their money somewhere else ;) Thanks, Philipp Then don't use that .. There are some software slave implementations out there. One is... and there are others. http://sourceforge.net/p/ecslave/wiki/Howto/ Then you get to use standard tools like Wireshark to figure out what is not working... http://digital.ni.com/public.nsf/allkb/6F063F1A993F6A4786257BB10041EEEA That's a lot further along than rolling your own, although it might be an overkill for what you want. If you don't want to do this then you can do some basic TCP send and receive and make up your own basic protocols to move data between devices, but that can quickly turn into a wheel reinvention project on its own. Dave -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
On 8 June 2015 at 18:46, Dave Cole linuxcncro...@gmail.com wrote: make up your own basic protocols to move data between devices, but that can quickly turn into a wheel reinvention project on its own. I wonder if the Mesa Smart Serial protocol would work? -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
As has been stated, Ethernet has lots of advantages. We use it for a real time control network (loop control 1kHz.) We just use an unused ethertype. All other stuff on the network will thus ignore the data and we don't need to have an IP stack (we do since we also run web traffic, but our control strips out the dedicated packets before the IP stack even sees them.) Main advantages to 10/100bT are electrical isolation (no ground loops!), high noise immunity, and ubiquitous cabling. A phy and connector are only a buck or two cost adder as the microcontroller typ has the mac built-in. Though if you want to do two ethernet ports your choice of controllers is more limited w/ built in dual macs. SERCOS solves that w/ an asic/fpga (+ licensing) but probably overkill for what you need. SMD On Mon, Jun 8, 2015 at 12:06 PM, Philipp Burch p...@hb9etc.ch wrote: Hi Dave! On 08.06.2015 15:43, Dave Cole wrote: ___ From the Ethercat Technology Group membership application page: The membership cost is pretty low... !!! :-) And there are some sample Ethercat master and slave source code available http://www.ethercat.org/en/products/4F84049B9950437FB34749A52AB20786.htm http://www.ethercat.org/en/products/54FA3235E29643BC805BDD807DF199DE.htm There is also at least one Ethercat open source master repository out there.. http://sourceforge.net/projects/soem.berlios/ Dave Good to know that it's free of charge. But since I'm mainly interested in the slave part, things are not that easy: Their slave sample code is for a microncontroller interfacing the EtherCAT-ASIC, so they're just making their money somewhere else ;) Thanks, Philipp -- ___ 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] Serial FPGA buses/interconnections [Was: Sandy box]
Philipp, You should look at the ethernet-based system Peter Wallace created for the Mesa cards. The FPGA firmware and drivers for the Mesa system is open source. The 7I92 or 7I80DB should have some code examples you can look at. -- Ralph From: Philipp Burch [p...@hb9etc.ch] Sent: Monday, June 08, 2015 9:06 AM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box] Hi Dave! On 08.06.2015 15:43, Dave Cole wrote: ___ From the Ethercat Technology Group membership application page: The membership cost is pretty low... !!! :-) And there are some sample Ethercat master and slave source code available http://www.ethercat.org/en/products/4F84049B9950437FB34749A52AB20786.htm http://www.ethercat.org/en/products/54FA3235E29643BC805BDD807DF199DE.htm There is also at least one Ethercat open source master repository out there.. http://sourceforge.net/projects/soem.berlios/ Dave Good to know that it's free of charge. But since I'm mainly interested in the slave part, things are not that easy: Their slave sample code is for a microncontroller interfacing the EtherCAT-ASIC, so they're just making their money somewhere else ;) Thanks, Philipp -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
While waiting for experts to respond I did some research on this interesting topics ... On 06/06/2015 01:19 PM, Philipp Burch wrote: Hi everyone, when we're talking about buses and interfaces, I'd like to bring up another topic concerning me recently: We're building some kind of PLC and motion controller mainly for internal uses, which is built around FPGAs. Our FPGA configs are crafted specifically for what the devices need to do, so there is no softcore or other microcontroller around. We now have a simple serial interface connecting multiple boards using differential pairs (RS-485-like) for RX and TX, transmitting frames of some 64 bits each. This works, but is obviously completely proprietary. Nothing wrong with being proprietary if nothing else out there suits your needs. However, when it comes to communications between logical devices you have to pay the price. Either you need to increase complexity for more reliable connections or use simpler protocols for lower HW costs. Ethernet interface chips are low cost these days, many hobby SBCs come with it. Benefits in using them is in their power to handle the TCP/IP connection without more than dumping bytes in and out of it's registers something most microcontrollers can easily do these days. Hence the question: Are there standard interfaces (call them buses if you like, I don't mind) of similar complexity with open specifications around? I personally like the idea of the summation frame method (Summenrahmenverfahren in German) as is used by EtherCAT, but this interface is overkill for us and also not open unless you are some kind of member. I found Interbus which seems to fit quite ideally, but, again, is not as open as I'd like it to be and it also looks to be kind of obsolete. Rough requirements would be: - Usable for daisy-chaining (no common bus) Wouldn't failure in any single link bring everything down? Fibre channel Arbitrated loop (FC-AL) and Tokenring work fall in that category. Each host has to pass the message along the line so there is a delay between the first and last host. - Data rate somewhere in the range 1Mbps .. 10Mbps - Serial with exactly one RX and one TX pair in each link What's the max distance between the hosts? What are electrical characteristics for connections between the hosts? There are other considerations that need to be looked at: how many units are connected in the chain? How do you implement the communication part? Microprocessor? ASIC? Do you need isolation between them? CAT-6 cabling would likely fit the job as far as physical connections and relative distance go. Low cost, easy to connect to hubs or switches. Advantage of ethernet is in possibility to wrap any protocol into TCP/IP and route it elsewhere. Not deterministic of course but possibly good enough for remote troubleshooting or monitoring. On the other hand, nobody prevents you to write your own version of network protocol. UDP came to mind first but because it's not reliable I did additional research and found Reliable User Datagram Protocol https://en.wikipedia.org/wiki/Reliable_User_Datagram_Protocol It's not a formal standard or widely used but the description is available https://tools.ietf.org/html/draft-ietf-sigtran-reliable-udp-00 It seems very simple to me so it would not be too hard to write a driver I think. - Suitable for deterministic cyclic transfers with some tens of bytes each Not sure how you can do that without a dedicated clock line. Any ideas, hints, comments? Regards, Philipp If nothing else, just searching around and reading responses from others I learned a lot. -- Rafael Where's my floppy disk? -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi, right now I don't have the time to follow the thread, and maybe it's been mentioned already, but you might want to look at Powerlink as well: http://en.wikipedia.org/wiki/Ethernet_Powerlink A few years back I looked for a real time Ethernet system and found Powerlink simpler than EtherCAT. The project died in a very early stage so I can't contribute any relay experiences in using or implementing it. See you Flo -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
On 6/6/2015 7:06 PM, Gene Heskett wrote: On Saturday 06 June 2015 16:52:08 Dave Cole wrote: I've been around for a while and worked with current loop serial interfaces, rs232, rs422/485, Ethernet (back when thicknet was standard) etc. Why in world would you not use Ethernet??It leaves you with so many options that are not available with RS485. I would join the Ethercat group, pay them some $$, get some source code and use what has already been developed and use every tool that they have already developed. No need to reinvent the wheel. Dave All well and good Dave, but how do we, in a cashless group, manage to find the sheckles to pay for a seat at that table? And how much is that seat, one time or annual dues? Heck of a good bunch questions, that. FWIW, I once enquired about a seat at the USB table. But $25k a year was not in my budget. Cheers, Gene Heskett ___ From the Ethercat Technology Group membership application page: The membership cost is pretty low... !!! :-) And there are some sample Ethercat master and slave source code available http://www.ethercat.org/en/products/4F84049B9950437FB34749A52AB20786.htm http://www.ethercat.org/en/products/54FA3235E29643BC805BDD807DF199DE.htm There is also at least one Ethercat open source master repository out there.. http://sourceforge.net/projects/soem.berlios/ Dave Apply for Membership If you are interested in becoming a member of the EtherCAT Technology Group, please proceed the following steps: * Contact http://www.ethercat.org/en/contact.html the ETG Headquarters or ask your local ETG office by phone or email. * All necessary information, e.g. requirements as well as the membership application form will be provided via email by ETG Headquarters. Membership is free of charge. You can download the ETG Membership By-Laws http://www.ethercat.org/en/downloads/downloads_6820D9C60B074CF9B9167468468C9B36.htm within the download section. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
On Monday 08 June 2015 09:43:42 Dave Cole wrote: On 6/6/2015 7:06 PM, Gene Heskett wrote: On Saturday 06 June 2015 16:52:08 Dave Cole wrote: I've been around for a while and worked with current loop serial interfaces, rs232, rs422/485, Ethernet (back when thicknet was standard) etc. Why in world would you not use Ethernet??It leaves you with so many options that are not available with RS485. I would join the Ethercat group, pay them some $$, get some source code and use what has already been developed and use every tool that they have already developed. No need to reinvent the wheel. Dave All well and good Dave, but how do we, in a cashless group, manage to find the sheckles to pay for a seat at that table? And how much is that seat, one time or annual dues? Heck of a good bunch questions, that. FWIW, I once enquired about a seat at the USB table. But $25k a year was not in my budget. Cheers, Gene Heskett ___ From the Ethercat Technology Group membership application page: The membership cost is pretty low... !!! :-) And there are some sample Ethercat master and slave source code available http://www.ethercat.org/en/products/4F84049B9950437FB34749A52AB20786.h tm http://www.ethercat.org/en/products/54FA3235E29643BC805BDD807DF199DE.h tm There is also at least one Ethercat open source master repository out there.. http://sourceforge.net/projects/soem.berlios/ Dave Apply for Membership If you are interested in becoming a member of the EtherCAT Technology Group, please proceed the following steps: * Contact http://www.ethercat.org/en/contact.html the ETG Headquarters or ask your local ETG office by phone or email. * All necessary information, e.g. requirements as well as the membership application form will be provided via email by ETG Headquarters. Membership is free of charge. You can download the ETG Membership By-Laws http://www.ethercat.org/en/downloads/downloads_6820D9C60B074CF9B91674 68468C9B36.htm within the download section. That is sure a heck of a lot friendlier than the USB working group was. They seemed to have a 20 foot tall handyman jack under their nose. Unfortunately I am not a networking guru, just good enough that there is not and likely never will be a working copy of N-M on any of my boxen. I nuke it forthwith after the install because that is the only way I can keep it from mucking with my local settings, once it tore up my resolv.conf before I could do a chattr +i on it. It has also torn up my hostname a couple times. So since its very low cost, as in free, and there is working code I presume, it wouldn't be a huge project to make up such a network IF the small packets can make it thru a COTS $40 hub. I assume it can use our existing rj45 stuff? Cheers, Gene Heskett -- There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Genes Web page http://geneslinuxbox.net:6309/gene -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
On 8 June 2015 at 15:58, Gene Heskett ghesk...@wdtv.com wrote: I assume it can use our existing rj45 stuff? It is already possible to use EtherCAT with LinuxCNC, and some people are doing it with good results. It would probably have been incorporated into the main LinuxCNC distrbution by now were it not for the fact that the licensing situation is tricky. You need to sign up to the EtherCAT license if you are providing an EtherCAT Master. If LinuxCNC incorporated the EtherLab(?) clode then LinuxCNC would be providing a means for LinuxCNC users to implement an EtherCAT Master. So there would be an implicit _extra_ license on top of the GPL License of LinuxCNC. And that's not allowed under GPL. At least, that is how I remember it last time this was discussed. It's a pity, EtherCAT is cool. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi Flo! On 08.06.2015 15:50, Florian Rist wrote: Hi, right now I don't have the time to follow the thread, and maybe it's been mentioned already, but you might want to look at Powerlink as well: http://en.wikipedia.org/wiki/Ethernet_Powerlink A few years back I looked for a real time Ethernet system and found Powerlink simpler than EtherCAT. The project died in a very early stage so I can't contribute any relay experiences in using or implementing it. See you Flo Thanks. It also uses Ethernet, so it's not exactly what I'm looking for. But if we should really stick to something Ethernet-based, it would surely be worth a thought as well. Cheers, Philipp signature.asc Description: OpenPGP digital signature -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi Dave! On 08.06.2015 15:43, Dave Cole wrote: ___ From the Ethercat Technology Group membership application page: The membership cost is pretty low... !!! :-) And there are some sample Ethercat master and slave source code available http://www.ethercat.org/en/products/4F84049B9950437FB34749A52AB20786.htm http://www.ethercat.org/en/products/54FA3235E29643BC805BDD807DF199DE.htm There is also at least one Ethercat open source master repository out there.. http://sourceforge.net/projects/soem.berlios/ Dave Good to know that it's free of charge. But since I'm mainly interested in the slave part, things are not that easy: Their slave sample code is for a microncontroller interfacing the EtherCAT-ASIC, so they're just making their money somewhere else ;) Thanks, Philipp signature.asc Description: OpenPGP digital signature -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi Dave! On 06.06.2015 22:52, Dave Cole wrote: I've been around for a while and worked with current loop serial interfaces, rs232, rs422/485, Ethernet (back when thicknet was standard) etc. Why in world would you not use Ethernet??It leaves you with so many options that are not available with RS485. I would join the Ethercat group, pay them some $$, get some source code and use what has already been developed and use every tool that they have already developed. Ethernet would be fine, yes, but also very complex from the hardware and low-level software point of view. While thinking about it, I remember that Beckhoff has some EtherCAT devices which use an LVDS interface instead of real Ethernet (for very local connections), so maybe this would still be an option, though... No need to reinvent the wheel. That's why I'm asking for something standardized and open ;) Thanks, Philipp signature.asc Description: OpenPGP digital signature -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Thats what crowdfunding is made for. Think about solutions, not problems. On June 7, 2015 1:06:00 AM CEST, Gene Heskett ghesk...@wdtv.com wrote: On Saturday 06 June 2015 16:52:08 Dave Cole wrote: I've been around for a while and worked with current loop serial interfaces, rs232, rs422/485, Ethernet (back when thicknet was standard) etc. Why in world would you not use Ethernet??It leaves you with so many options that are not available with RS485. I would join the Ethercat group, pay them some $$, get some source code and use what has already been developed and use every tool that they have already developed. No need to reinvent the wheel. Dave All well and good Dave, but how do we, in a cashless group, manage to find the sheckles to pay for a seat at that table? And how much is that seat, one time or annual dues? Heck of a good bunch questions, that. FWIW, I once enquired about a seat at the USB table. But $25k a year was not in my budget. Cheers, Gene Heskett -- There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Genes Web page http://geneslinuxbox.net:6309/gene -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi Alexander! On 07.06.2015 12:47, Alexander Rössler wrote: CANopen might be what you are searching for. Thanks for the hint, I'll have a look. From what I've seen so far, CAN(open) has a bus topology (parallel connections of all devices), which is not exactly what I'm looking for, but maybe this does not make too much of a difference. Regards, Philipp signature.asc Description: OpenPGP digital signature -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
CANopen might be what you are searching for. On June 6, 2015 10:19:45 PM CEST, Philipp Burch p...@hb9etc.ch wrote: Hi everyone, when we're talking about buses and interfaces, I'd like to bring up another topic concerning me recently: We're building some kind of PLC and motion controller mainly for internal uses, which is built around FPGAs. Our FPGA configs are crafted specifically for what the devices need to do, so there is no softcore or other microcontroller around. We now have a simple serial interface connecting multiple boards using differential pairs (RS-485-like) for RX and TX, transmitting frames of some 64 bits each. This works, but is obviously completely proprietary. Hence the question: Are there standard interfaces (call them buses if you like, I don't mind) of similar complexity with open specifications around? I personally like the idea of the summation frame method (Summenrahmenverfahren in German) as is used by EtherCAT, but this interface is overkill for us and also not open unless you are some kind of member. I found Interbus which seems to fit quite ideally, but, again, is not as open as I'd like it to be and it also looks to be kind of obsolete. Rough requirements would be: - Usable for daisy-chaining (no common bus) - Data rate somewhere in the range 1Mbps .. 10Mbps - Serial with exactly one RX and one TX pair in each link - Suitable for deterministic cyclic transfers with some tens of bytes each Any ideas, hints, comments? Regards, Philipp -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
On Sunday 07 June 2015 07:13:36 Philipp Burch wrote: Hi Alexander! On 07.06.2015 12:47, Alexander Rössler wrote: CANopen might be what you are searching for. Thanks for the hint, I'll have a look. From what I've seen so far, CAN(open) has a bus topology (parallel connections of all devices), which is not exactly what I'm looking for, but maybe this does not make too much of a difference. Regards, Philipp I looked at a page fron NI, looks like tolerable latencies could be obtained, and at 1Mbit/sec, I'd say fast enough. But whats the cost of the net on a per port basis? I didn't get that far as I was forced back to the heating pad. To me, its a non-starter if the card needs local power, and costs more than a DM542 driver. And I did find some prices, but they started at about $275 and went up another $200 for the more capable ones. That makes PCW's prices pretty appetizing. For someone using steppers, the 5i25 seems like a heck of a deal. I have an elderly HP desktop tower with a 1Ghz athlon in it, but will have to see what sort of bus it has if I can run this mill with that card in it. If I can, that would seem to solve the lack of any more new D525MW motherboards. Not ideal of course as it doesn't have enough ram at 320megs, but I started out doing SW stepping on a motherboard with a 1.6Ghz athlon on it. I originally set it up in the garage with the idea of listening to Pandora on it, but it wasn't even fast enough for that. So I'll put the 5i25 I put in the toy mills atom box but haven't configured it yet, in this curb pickup, if the card is bus compatible. I've already used mesaflash to put the same firmware that the lathes card has in it. With both parports in use, thats 8 axis's worth of drives 2 encoder inputs. Seems like I ought to be able to make this Grizzly bear dance my favorite dance steps. Cheers, Gene Heskett -- There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Genes Web page http://geneslinuxbox.net:6309/gene -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
Hi everyone, when we're talking about buses and interfaces, I'd like to bring up another topic concerning me recently: We're building some kind of PLC and motion controller mainly for internal uses, which is built around FPGAs. Our FPGA configs are crafted specifically for what the devices need to do, so there is no softcore or other microcontroller around. We now have a simple serial interface connecting multiple boards using differential pairs (RS-485-like) for RX and TX, transmitting frames of some 64 bits each. This works, but is obviously completely proprietary. Hence the question: Are there standard interfaces (call them buses if you like, I don't mind) of similar complexity with open specifications around? I personally like the idea of the summation frame method (Summenrahmenverfahren in German) as is used by EtherCAT, but this interface is overkill for us and also not open unless you are some kind of member. I found Interbus which seems to fit quite ideally, but, again, is not as open as I'd like it to be and it also looks to be kind of obsolete. Rough requirements would be: - Usable for daisy-chaining (no common bus) - Data rate somewhere in the range 1Mbps .. 10Mbps - Serial with exactly one RX and one TX pair in each link - Suitable for deterministic cyclic transfers with some tens of bytes each Any ideas, hints, comments? Regards, Philipp signature.asc Description: OpenPGP digital signature -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
I've been around for a while and worked with current loop serial interfaces, rs232, rs422/485, Ethernet (back when thicknet was standard) etc. Why in world would you not use Ethernet??It leaves you with so many options that are not available with RS485. I would join the Ethercat group, pay them some $$, get some source code and use what has already been developed and use every tool that they have already developed. No need to reinvent the wheel. Dave On 6/6/2015 4:19 PM, Philipp Burch wrote: Hi everyone, when we're talking about buses and interfaces, I'd like to bring up another topic concerning me recently: We're building some kind of PLC and motion controller mainly for internal uses, which is built around FPGAs. Our FPGA configs are crafted specifically for what the devices need to do, so there is no softcore or other microcontroller around. We now have a simple serial interface connecting multiple boards using differential pairs (RS-485-like) for RX and TX, transmitting frames of some 64 bits each. This works, but is obviously completely proprietary. Hence the question: Are there standard interfaces (call them buses if you like, I don't mind) of similar complexity with open specifications around? I personally like the idea of the summation frame method (Summenrahmenverfahren in German) as is used by EtherCAT, but this interface is overkill for us and also not open unless you are some kind of member. I found Interbus which seems to fit quite ideally, but, again, is not as open as I'd like it to be and it also looks to be kind of obsolete. Rough requirements would be: - Usable for daisy-chaining (no common bus) - Data rate somewhere in the range 1Mbps .. 10Mbps - Serial with exactly one RX and one TX pair in each link - Suitable for deterministic cyclic transfers with some tens of bytes each Any ideas, hints, comments? Regards, Philipp -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Serial FPGA buses/interconnections [Was: Sandy box]
On Saturday 06 June 2015 16:52:08 Dave Cole wrote: I've been around for a while and worked with current loop serial interfaces, rs232, rs422/485, Ethernet (back when thicknet was standard) etc. Why in world would you not use Ethernet??It leaves you with so many options that are not available with RS485. I would join the Ethercat group, pay them some $$, get some source code and use what has already been developed and use every tool that they have already developed. No need to reinvent the wheel. Dave All well and good Dave, but how do we, in a cashless group, manage to find the sheckles to pay for a seat at that table? And how much is that seat, one time or annual dues? Heck of a good bunch questions, that. FWIW, I once enquired about a seat at the USB table. But $25k a year was not in my budget. Cheers, Gene Heskett -- There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Genes Web page http://geneslinuxbox.net:6309/gene -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
