7i77 lost connection while encoder counts (PREEMPT-RT)
- lonnox
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i got a problem in a linuxcnc mesa card configuration. if the encoders of the 7i77 counts for a while, the 7i77 lost connection and linuxcnc stops working. Its not possible to calibrate the connected drives because it is not possible to drive more than a few cm before the error comes up.
If the error occurs the green flashing led on the 7i77 turns to constant red and pin hm2_5i25.0.write.time did not change anymore. LinuxCNC itself did only responds very slowly, the rest of the os is working normal. On closing i got an timeout error from linuxCNC.
I think the problem is related to the preempt kernel.
I retrofitted about 20 different machines to linuxCNC with mesa cards custom panels and custom HAL components and i got 2 configurations that shows this error. The configuration system i build to analyse the error consist only of the live image (2.9.4) and 6i25, 7i77 and an encoder.
what did i try so far without a positve result:
- tried 2 different pc with different mainboards (Biostar B450MH, ASUS Prime A320M-R), ram, ssd and graphic card
- tried different 7i77 and 6i25 cards
- tried different encoders (5V, 3V)
- tried debian bookworm and debian buster (with PREEMPT-RT)
- tried different jumper settings
- tried different firmware on 6i25
- tried different encoder inpust
- changed configuration string
- verified that latency is not the problem (less than 50000 servo thread jitter)
- verified that its not triggered by the mesa watchdog (set it to 10seconds)
- viewed the journalctl logs (no hints occour that relates to the problem)
- viewed linuxCNC debug output by running it in the terminal in max debug-level
- the problem did not occur on debian wheezy
- the problem did not occur on debian bookworm with rtai kernel
- the problem did not occur on all mainboards
Mayby this is a kind of a solution but it would be the better way, to find what of the preempt kernel causes the problem i quess. So if anyone has an idea how the problem can be solved, please feel free to answer the post.
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- PCW
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(current is 6.16)
Does dmesg show any errors?
(clear the dmesg log first, run LinuxCNC and then run dmesg again)
Is there any PCIE power management enabled in the BIOS?
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- tommylight
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Most probably weak 5V power supply and/or encoder drawing more than 50-60mA.Hi folks,
i got a problem in a linuxcnc mesa card configuration. if the encoders of the 7i77 counts for a while, the 7i77 lost connection and linuxcnc stops working.
Easily checked if you have a DVM with min/max memory, and measuring 5V at the 7i77 connector and at the encoder connector.
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- PCW
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Suggests this is a PCIE communication issue and probably
not related to 7I77 5V
It may indicate a grounding/EMI issue. Do you have an issue when
the 7I77 in not connected to the rest of the machine?
This is why i asked for a dmesg log as PCIE issues should show up there.
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- lonnox
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And in the beginning the encoder inputs were connected to a 5V glas scale.
We also tried the encoder outputs of an ESTUN Servo drive.
All gave the same (bad) result.
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- PCW
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Did you check dmesg kernel log?
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- lonnox
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EMI was also one of my suggestions, at the time where the 6i25, 7i77 and the PC was part of the machine, so i decide to use shielded wires between the servos and their drives. Wires from drive to mesa are shielded too.pin hm2_5i25.0.write.time did not change anymore.
Suggests this is a PCIE communication issue and probably
not related to 7I77 5V
It may indicate a grounding/EMI issue. Do you have an issue when
the 7I77 in not connected to the rest of the machine?
This is why i asked for a dmesg log as PCIE issues should show up there.
But the problem was the same.
Now i build a system with only the cards, the pc and rotary encoder but the problem is still the same.
Checked dmesg and there maby we have a track, the problem occur immediately after starting linuxCNC, this is the output:Does dmesg show any errors?
[ 1323.534393] mce: Uncorrected hardware memory error in user-access at fcb01000
[ 1323.534404] Memory failure: 0xfcb01: memory outside kernel control
[ 1323.534405] mce: Memory error not recovered
[ 1323.534528] mce: [Hardware Error]: Machine check events logged
[ 1323.534532] [Hardware Error]: Uncorrected, software restartable error.
[ 1323.534535] [Hardware Error]: CPU:3 (17:8:2) MC0_STATUS[-|UE|MiscV|AddrV|-|-|-|UECC|-|Poison|-]: 0xbc002800000c0135
[ 1323.534541] [Hardware Error]: Error Addr: 0x00000000fcb01000
[ 1323.534542] [Hardware Error]: IPID: 0x000000b000000000
[ 1323.534544] [Hardware Error]: Load Store Unit Ext. Error Code: 12, DC Data error type 1 and poison consumption.
[ 1323.534546] [Hardware Error]: cache level: L1, tx: DATA, mem-tx: DRD
Indead there was, but i disabled it before doing dmesg.Is there any PCIE power management enabled in the BIOS?
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