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Is The PCI-E Parallel Port Card The (Likely) Culprit for These Issues?
- tommylight
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26 Mar 2023 02:10 #267515
by tommylight
Replied by tommylight on topic Is The PCI-E Parallel Port Card The (Likely) Culprit for These Issues?
There is no way of being sure the latency is OK, the tests only help narrow down the hardware that can or can not be used.
To be sure, you need to run the PC connected to the controller or with active parallel port while LinuxCNC is running for 2 to 3 days non stop, while doing other stuff on the PC, youtube, copy, especially maximizing and minimizing the youtube player tends to cause latency excursions.
And there are ways of dealing even with less than ideal latency, making the servo/base period longer sometimes can prove enough to make a usable system, although it might limit the step rate.
To be sure, you need to run the PC connected to the controller or with active parallel port while LinuxCNC is running for 2 to 3 days non stop, while doing other stuff on the PC, youtube, copy, especially maximizing and minimizing the youtube player tends to cause latency excursions.
And there are ways of dealing even with less than ideal latency, making the servo/base period longer sometimes can prove enough to make a usable system, although it might limit the step rate.
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- Scrappy_000
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30 Mar 2023 02:48 #267881
by Scrappy_000
Replied by Scrappy_000 on topic Is The PCI-E Parallel Port Card The (Likely) Culprit for These Issues?
It took a few days before I was able to get back to doing much on this, but I am pleased to say that all of the issues seem to have been resolved. Since yesterday evening, the port hasn't become disabled, its addresses haven't changed, the "Unexpected realtime delay on task 0 with period 100000" warning has not appeared, and the steppers are all running smoothly. So, what was the fix? I replaced the Syba SD-PEX10005 with a
Vantec UGT-PCE10PL
.
As mentioned a few posts ago, my intent was to install the RTAI kernel as my next step, but while discussing the issues with a friend, he offered to let me try out a spare UGT-PCE10PL he had sitting around, with the results as stated above. Installing the RTAI kernel is not off the table, but with the issues apparently being resolved and the latency test now under 6,000, I'm going to stick with this configuration unless there are compelling reasons to implement further changes.
As mentioned a few posts ago, my intent was to install the RTAI kernel as my next step, but while discussing the issues with a friend, he offered to let me try out a spare UGT-PCE10PL he had sitting around, with the results as stated above. Installing the RTAI kernel is not off the table, but with the issues apparently being resolved and the latency test now under 6,000, I'm going to stick with this configuration unless there are compelling reasons to implement further changes.
The following user(s) said Thank You: tommylight, RobC
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