Go into BIOS and disable everything that you do not need, like floppy drive and floppy controller (disabling just the drive does nothing as the controller is still in use, and since it uses IRQ it will impact latency), modem, power savings, speed step, put it in performance mode etc.
What Dell?
Sorry for the delay but things were working and I was playing!
I had disabled things in the BIOS as you suggested.
I believe I had been seeing latency numbers in the 1 ms range but testing now I'm seeing 7ms. I could be remembering them wrong or something has changed. I'm not sure. I do have 2 ethernet ports. The motherboard is connected to the Mesa board and the PCI ethernet is connected to the home network.
Edit. This is incorrect. Somehow I booted into the non-RT kernel. Servo = 67us Base 102us.
Dell Dimension 2400 series.
New issues.
I hooked up the limit switches but was unable to power the whole board with TB3 and TB1. The field power LED lit but not the main logic section. I was using a single power supply. TB3 22 and 23, with 21 and 24 jumpered to TB1 1 and 8. W1 to the left. I finally gave up and went back to 2 supplies, one 12v for field and 1 5v on P3. I had been using 5V on P3 when things were working.
Limit switches seem to work as I get a message for each axis as I trigger them manually. I do get a new error message.
Edit: This appears to be due to the non-RT kernel as well.
hm2/gm2_7i76e.0: Smart Serial port 0: DoIt not cleared from previous servo thread: Servo rate probably too fast. This message will not be repeated but the hm2_7i76e.0.serial.fault-count pin will indicate it this is happening frequently.
The bad news is my steppers are back to not working. I verified the watchdog is still at 50ms. I tried to go back to the .hal file I posted earlier with the watchdog set up to 50ms but that doesn't work either. This may be a different symptom as before as I can't get it work at all where before it would work sometime.
Is there additional logging I can enable? Could I have killed something when I tried to power the board with 1 supply from TB1 and TB3? P3 was unconnected at this time.
Thanks,
Steve
Last edit: 7 years 10 months ago by steveb48. Reason: Error in latency measurements
TB1 (field power) is completely isolated from TB3 unregulated power unless you use a common power source. There is no problem using a common power for both except that you lose isolation of the field power section (12/24V IO) from the logic section (step/DIR pins, encoder etc)
If you cannot power the logic section of the card via the unregulated input on TB3
with a correct polarity 8 to 35 VDC source, this indicates a card problem ( connection error or damaged switching regulator?)
The sserial errors are typical if you have real time issues.
Did you disable all power management options in the hos PCs BIOS?
If you have a Intel MAC on the host PC did you disable IRQ coalescing
as mentioned in the hm2_eth manual page?
A quick check to see if you have usable Ethernet latency is to ping the 7I76E card
If you get times > 300 usec or so its probably not usable at 1 KHz without some fixes
A better check is to look at all the xxx.tmax parameters after linuxcnc has run for a while (from a terminal when linuxcnc is running):
halcmd show param *.tmax
These are all reported in units of CPU clock cycles
Peter,
Thanks so much for all your guidance. On New Year's Day as well!
I cannot power the logic part of the board from TB3. I noticed with an ohm meter that there is not continuity between TB3 pins 21 and 22. Seems like they would be tied together. Applying + to either doesn't power up the logic part. There is no chance I could have applied too much voltage as my programable power supply only goes to 20v. It is possible that I might have put 6v onto P3 by accident.
The serial error was due to me booting into the wrong kernel. I have both 3.2 and 3.4 installed but only 3.2 has Preempt RT. This also caused my bogus latency measurement. I only had one drink last night!
pinging the board returns values between 100us and 115us.
This was working. With the limit switches configured, I get messages when I trigger them manually but no steppers. I tried removing them from the config and I have the same problem.
Unfortunately, putting 6V+ on P3 could easily damage the 5V parts on the 7I76E
including the drivers for the Step/Dir pins (I'm not sure this has happened but its a possibility)
