Mesa 7i76E pc requirements
03 Oct 2016 06:45 #81170
by vmihalca
Mesa 7i76E pc requirements was created by vmihalca
Hello,
I intend to buy Mesa 7i76E and I would like to know if there are special PC requirements I should be aware of.
Does the latency of the pc matters if I'm using this board?
I intend to buy Mesa 7i76E and I would like to know if there are special PC requirements I should be aware of.
Does the latency of the pc matters if I'm using this board?
Please Log in or Create an account to join the conversation.
04 Oct 2016 15:53 #81217
by andypugh
Replied by andypugh on topic Mesa 7i76E pc requirements
Latency matters a bit, but not as much as for a parallel-port based system.
A board with more than one ethernet port might be handy.
I believe that some ethernet chips are known to work better than others. PCW might be able to add detail to that.
A board with more than one ethernet port might be handy.
I believe that some ethernet chips are known to work better than others. PCW might be able to add detail to that.
Please Log in or Create an account to join the conversation.
04 Oct 2016 17:07 #81224
by vmihalca
Replied by vmihalca on topic Mesa 7i76E pc requirements
In the latency test I've made max jitter is:
Servo Thread: 39553 ns
Base Thread: 13710 ns
I have read all that I could find about this board, it appears listed in mesa cards drop down in my linux cnc 2.7.0
I just need some confirmations I'm not buying something unreliable for a lathe with spindle encoder.
Servo Thread: 39553 ns
Base Thread: 13710 ns
I have read all that I could find about this board, it appears listed in mesa cards drop down in my linux cnc 2.7.0
I just need some confirmations I'm not buying something unreliable for a lathe with spindle encoder.
Please Log in or Create an account to join the conversation.
04 Oct 2016 17:11 #81225
by andypugh
Replied by andypugh on topic Mesa 7i76E pc requirements
That should be fine.In the latency test I've made max jitter is:
Servo Thread: 39553 ns
Base Thread: 13710 ns
I am not sure which board you are talking about here. The 7i76E or the PC.I have read all that I could find about this board, it appears listed in mesa cards drop down in my linux cnc 2.7.0
I just need some confirmations I'm not buying something unreliable for a lathe with spindle encoder.
Please Log in or Create an account to join the conversation.
04 Oct 2016 17:16 #81226
by vmihalca
Replied by vmihalca on topic Mesa 7i76E pc requirements
I'm talking about the mesa 7i76e.
Wondering if its as reliable as the PCI version + daugherboard.
I like the idea of having all the electronic self-contained in a cabinet the pc without any hardware dependencies.
Wondering if its as reliable as the PCI version + daugherboard.
I like the idea of having all the electronic self-contained in a cabinet the pc without any hardware dependencies.
Please Log in or Create an account to join the conversation.
04 Oct 2016 17:42 - 04 Oct 2016 17:44 #81227
by PCW
Replied by PCW on topic Mesa 7i76E pc requirements
The PC's latency is not terribly important but it must be able to maintain reliable
communication with the 7I76E at a 1 KHz rate
Typically this requires a peak latency of better than 200 usec or so, but note this is latency with
a Preempt-RT kernel, not the stock RTAI kernel on the LinuxCNC live CD image
In general faster machines are better with Preempt-RT (J1900s and J1800s are good, G3258 and similar Pentiums are excellent, Core Duos are good, some AMD are OK, I do not recommend older Atoms like D525s,D2XXXs)
For Ethernet interfaces, both Realtek and Intel are fine, avoid Broadcom and Atheros like the plague
On Intel Ethernet you need to turn off receive IRQ coalescing with something like this:
sudo ethtool -C eth2 rx-usecs 0
communication with the 7I76E at a 1 KHz rate
Typically this requires a peak latency of better than 200 usec or so, but note this is latency with
a Preempt-RT kernel, not the stock RTAI kernel on the LinuxCNC live CD image
In general faster machines are better with Preempt-RT (J1900s and J1800s are good, G3258 and similar Pentiums are excellent, Core Duos are good, some AMD are OK, I do not recommend older Atoms like D525s,D2XXXs)
For Ethernet interfaces, both Realtek and Intel are fine, avoid Broadcom and Atheros like the plague
On Intel Ethernet you need to turn off receive IRQ coalescing with something like this:
sudo ethtool -C eth2 rx-usecs 0
Last edit: 04 Oct 2016 17:44 by PCW.
Please Log in or Create an account to join the conversation.
05 Oct 2016 07:19 #81245
by Hakan
Replied by Hakan on topic Mesa 7i76E pc requirements
I recently built a PC with Z170 motherboard and Core i3-6100 www.gigabyte.us/products/product-page.aspx?pid=5518#ov in this small case www.chieftec.eu/en/chassis/itx-tower/ix-01b.html
See it as an example of a recent configuration.
Jitter is around 40000 ns.
It has been running 2.7.7 with the 7i76E for many hours, no problem.
I did set the rx-usecs to 0, but the last times the PC rebooted I have forgotten to set rx-usecs and it works anyway.
See it as an example of a recent configuration.
Jitter is around 40000 ns.
It has been running 2.7.7 with the 7i76E for many hours, no problem.
I did set the rx-usecs to 0, but the last times the PC rebooted I have forgotten to set rx-usecs and it works anyway.
Please Log in or Create an account to join the conversation.
05 Oct 2016 19:05 - 05 Oct 2016 19:16 #81268
by PCW
Replied by PCW on topic Mesa 7i76E pc requirements
Things may work at 1 KHz without setting the IRQ coalescing off but you will have less margin,
waste more CPU time in the LinucCNC servo thread, and probably not be able to run at faster thread rates
As a quick test you can ping the 7I76E before and after running the ethtool command and see the difference
EDIT: I think you can put the ethtool command in your etc/network/interfaces file
(to make it permanent)
waste more CPU time in the LinucCNC servo thread, and probably not be able to run at faster thread rates
As a quick test you can ping the 7I76E before and after running the ethtool command and see the difference
EDIT: I think you can put the ethtool command in your etc/network/interfaces file
(to make it permanent)
Last edit: 05 Oct 2016 19:16 by PCW.
Please Log in or Create an account to join the conversation.
Time to create page: 0.130 seconds