microcontroller vs parallel port
27 Mar 2021 01:12 #203761
by andypugh
If you are using Mesa (or General Mechatronics, or Moteonc, or Servo-to-Go) hardware you don't need a parallel port. LinuxCNC supports PCI, PCIe, Ethernet, SPI interfaces. The only thing that is not supported is USB, because USB allows multi-millisecond delays.
This is not to say that the future might not see a low-latency version of USB, but so far USB development has focussed on throughput rather than deterministic timing.
The only hardware interfaces that require a parallel port are Pico and Pluto. Pluto should probably be discounted, as it appears unreliable. Pico works well, and is well supported on this forum by the manufacturer. (as is Mesa)
It's worth noting that the Mesa firmware is Open Source, and people have built their own "Mesa" cards running stock or custom firmware but running with the LinuxCNC drivers.
Replied by andypugh on topic microcontroller vs parallel port
Seemed like the question was about using cheap buffered 3DP hardware/firmware and free software compared to LinuxCNC on a hard to find PC with a parallel port and addon controller(Mesa, etc).
If you are using Mesa (or General Mechatronics, or Moteonc, or Servo-to-Go) hardware you don't need a parallel port. LinuxCNC supports PCI, PCIe, Ethernet, SPI interfaces. The only thing that is not supported is USB, because USB allows multi-millisecond delays.
This is not to say that the future might not see a low-latency version of USB, but so far USB development has focussed on throughput rather than deterministic timing.
The only hardware interfaces that require a parallel port are Pico and Pluto. Pluto should probably be discounted, as it appears unreliable. Pico works well, and is well supported on this forum by the manufacturer. (as is Mesa)
It's worth noting that the Mesa firmware is Open Source, and people have built their own "Mesa" cards running stock or custom firmware but running with the LinuxCNC drivers.
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27 Mar 2021 05:28 #203774
by iplayfast
Replied by iplayfast on topic microcontroller vs parallel port
So I'm thinking for something to get my cnc-table up and running quickly a mesa plug and go kit.
On their site is 18 of em store.mesanet.com/index.php?route=product/category&path=83_84 and no description of the differences. Very frustrating, as there is $100 difference in prices but absolutely no guidance as to why I would want one over the other.
I've got a CNC Model 2006 R-2 similar to www.stevemeadedesigns.com/board/topic/20...iy-cnc-router-build/
I'm all set except the interface between pc and motor drivers. So looking for suggestions.
On their site is 18 of em store.mesanet.com/index.php?route=product/category&path=83_84 and no description of the differences. Very frustrating, as there is $100 difference in prices but absolutely no guidance as to why I would want one over the other.
I've got a CNC Model 2006 R-2 similar to www.stevemeadedesigns.com/board/topic/20...iy-cnc-router-build/
I'm all set except the interface between pc and motor drivers. So looking for suggestions.
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27 Mar 2021 10:28 #203789
by andypugh
1) 5i25 or 6i65. 5i25 is PCI. 6i25 is PCIe.
2) 7i77 - Servo use (encoders in, analogue out) 7i76 - stepper pulses out + spindle, 7i85 - steppers or serial + encoders
3) 7i76 / 7i76D or 7i77 / 7i77D - D means Sinking Outputs.
4) 7i85 v 7i85S - the 7i85 has 4 serial channels, 7i85S replaces those with differential outputs (normally used for step/dir)
As well as the plug-and-go kits, you could look at the 7i76E which is a version of the 7i76 with a built-in ethernet connection (so does not need the 5i25 / 6i25)
Replied by andypugh on topic microcontroller vs parallel port
So I'm thinking for something to get my cnc-table up and running quickly a mesa plug and go kit.
On their site is 18 of em store.mesanet.com/index.php?route=product/category&path=83_84 and no description of the differences.
1) 5i25 or 6i65. 5i25 is PCI. 6i25 is PCIe.
2) 7i77 - Servo use (encoders in, analogue out) 7i76 - stepper pulses out + spindle, 7i85 - steppers or serial + encoders
3) 7i76 / 7i76D or 7i77 / 7i77D - D means Sinking Outputs.
4) 7i85 v 7i85S - the 7i85 has 4 serial channels, 7i85S replaces those with differential outputs (normally used for step/dir)
As well as the plug-and-go kits, you could look at the 7i76E which is a version of the 7i76 with a built-in ethernet connection (so does not need the 5i25 / 6i25)
The following user(s) said Thank You: iplayfast
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27 Mar 2021 13:44 #203805
by arvidb
But this would be a completely different "breakout board" than the usual, buffered, "intelligent" type, and it would still require a realtime kernel. So we're right back at "the LinuxCNC way", but without e.g. the electrical benefits of Ethernet - galvanic isolation, shielding, cable length. So I don't really see the point.
Replied by arvidb on topic microcontroller vs parallel port
From a purely technical standpoint it should be possible today: high-speed (USB 2.0) isochronous endpoints have a guaranteed bus slot every 125 µs and a worst case roundtrip latency of two slots each direction, i.e. 500 µs. This type of endpoint is typically used for audio devices but could be used for machine control too.This is not to say that the future might not see a low-latency version of USB, but so far USB development has focussed on throughput rather than deterministic timing.
But this would be a completely different "breakout board" than the usual, buffered, "intelligent" type, and it would still require a realtime kernel. So we're right back at "the LinuxCNC way", but without e.g. the electrical benefits of Ethernet - galvanic isolation, shielding, cable length. So I don't really see the point.
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27 Mar 2021 16:31 #203811
by iplayfast
Replied by iplayfast on topic microcontroller vs parallel port
This is very useful.
I don't know how sinking/sourcing output applies to a motor driver. I'm using an hy-div-268-5a datasheetspdf.com/datasheet/HY-DIV268N-5A.html
I'm also very interested in the 7i76E you mentioned. Is it an easy setup?
I don't know how sinking/sourcing output applies to a motor driver. I'm using an hy-div-268-5a datasheetspdf.com/datasheet/HY-DIV268N-5A.html
I'm also very interested in the 7i76E you mentioned. Is it an easy setup?
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27 Mar 2021 20:22 #203833
by iplayfast
Replied by iplayfast on topic microcontroller vs parallel port
After watching a youtube video I saw that hy-div-268-5a are sinking io. In other words, they don't provide the power, they use it.
So I'm narrowing it down. Looking at the forum it looks like the 7i76E is difficult to set up, there is also the question of why it needs 28V which I don't have handy.
So my decision is
7I76-6I25 PLUG-N-GO KIT
(let me know if I'm making a mistake please. Ordering it on Monday)
So I'm narrowing it down. Looking at the forum it looks like the 7i76E is difficult to set up, there is also the question of why it needs 28V which I don't have handy.
So my decision is
7I76-6I25 PLUG-N-GO KIT
(let me know if I'm making a mistake please. Ordering it on Monday)
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27 Mar 2021 21:31 #203837
by tommylight
Replied by tommylight on topic microcontroller vs parallel port
7i76E needs 8 to 28V, so anything in-between works. And i would not call the setup hard in any way, pncconf should take care of that.
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27 Mar 2021 22:48 #203857
by andypugh
If you have a PCI slot, though, that is simpler to set up than Ethernet in some ways, and you retain the ethernet port for networking.
Replied by andypugh on topic microcontroller vs parallel port
7i76E needs 8 to 28V, so anything in-between works. And i would not call the setup hard in any way, pncconf should take care of that.
If you have a PCI slot, though, that is simpler to set up than Ethernet in some ways, and you retain the ethernet port for networking.
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28 Mar 2021 17:59 #203919
by iplayfast
Replied by iplayfast on topic microcontroller vs parallel port
It comes to mind that using the ethernet port or a pci/pcie card is no different than what I was suggesting in the first place. Your main pc running linuxcnc is talking to a peripheral that is controlling the stepper drivers. I wonder what sort of information is going through the ethernet cable?
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28 Mar 2021 18:28 #203923
by Aciera
Replied by Aciera on topic microcontroller vs parallel port
have you seen this thread:
forum.linuxcnc.org/27-driver-boards/4144...board?start=0#198959
Maybe you glean some information from that.
forum.linuxcnc.org/27-driver-boards/4144...board?start=0#198959
Maybe you glean some information from that.
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