Advanced Search

Did you check the the analog command (xx.n.7i76.0.0.spinout) in hal is as expected?
that is 1000 for a 1000 RPM command with a scale of 10000
(in case you have feedback in the PID setup and there is a encoder issue)

If the analog spindle output (when disconnected from the VFD) is non-linear
relative to xx.n.7i76.0.0.spinout pin, it likely means the the OP-AMP buffer
in the analog output circuit has been damaged, perhaps by EMI from the VFD

At lower end it's about twice the voltage, then the error gets lower as we go up. I also noticed spindle rpm glitching once. I have an encoder and had setup spindle at speed with that, That's how I noticed first. Then measured the voltages.

Even in this fuzzy state i do not think it is the board, i have over 70 or 80 (probably more) of them in daily use for over 10 years and none ever failed nor any hiccups nor any issues ever.
I'll shut up now ...
Then again moisture does cause issues ...

No not twisted for that, shielded, RG58 or RG59 antenna cable if you do not have anything thinner.
Twisted cables are not for analog use.

I am in the US. That vibration on analogout3 is the million dollar question. If I disconnect the wires on analogout0 the vibration completely goes away on analogout3.

I am using original wiring except for 8-10inches of twisted pairs for both analog signals to connect the original wiring to the mesa boards.

Let's wait for PCW I guess. There's no way I can get a replacement for this fast enough. If I can repair it it will be a great help.

harindugamlath wrote:

I Think you didn't get that it's voltage output that has changed.

Oh i did, but being deprived of sleep for 3 days and having now slept for 11 hours is messing my head up badly, so i urgently need a coffee or two.
Sorry.

Another look and...you are in US, that looks like 60Hz noise.
Edit:
I need a coffee or two, but still, why is that vibration on analogout3?

Thanks for the response! I’ve followed that outline pretty carefully but get stuck at setting P. It doesn’t matter what I set it to I can’t get rid of the vibration in the motor. If it’s too high or too low I get following errors but no value reduces the vibration to an acceptable level. The screenshot in the first post shows the minimum level of vibration I can get by changing P. I’ve tried increasing the dead band but that doesn’t seem to help unless it’s so big that it gives following errors.

No. It's just as before. I Think you didn't get that it's voltage output that has changed. it's sending out 2V instead of 1V. This one has been untouched since 2021. Mesa card is acting up.

Check the VFD, probably set at 0-5V instead of 0-10V.

forum.linuxcnc.org/10-advanced-configura...ning-detailed-how-to

Hi, This is a weird issue. For some reason analog output of the spindle of my 7i76D has changed overnight. It's roughly giving out twice the correct voltage at the low end and the error gets less at the top (10,000rpm)

This has worked fine since 2021 and I haven't touched any INI, HAL settings. Out of curiosity I measured the 10V power (which is bang on at 10.00V) and the output. If I command 1000rpm its giving out 2.1V which is way above. 0-10,000 rpm spindle (0-10V) It should be at around 1V @1000rpm right?
Never came across anything like this before. 

Is the digital potentiometer in the 7i76 failing? what should I do?

ok now hal_bridge has ok/cancel buttons that will close the notify error messages (if showing) or if a dialog is showing, enter ok / cancel or close.

Also the shutdown dialog can be set to have a countdown timer to automatically close the screen without clicking it.

Docs have been updated.

let me know how the ok/cancel pins work for you.

I’m working on a retrofit and I’m having trouble with oscillation on an analog velocity-controlled axis using existing Fanuc DC motors and drives.I have a Mesa 7i77EU for the FPGA, 7i85 for the encoders, and 7i83 for the analog outputs. I am using two outputs for each drive. one for a velocity command and one for a virtual tachometer. This is similar to how the original Fanuc controller was doing it.Current status:

• I have the analog outputs scaled correctly as far as I can tell. I measured the voltages going to the drive and they match the drive specs. 7V/2000RPM for velocity and 3V/1000RPM for the tachometer signal.
• With the velocity command wires disconnected from the drive, the system appears stable. The motor holds position well and resists manual twisting of the shaft.
• As soon as I connect the analog command wires to the drive, the axis begins oscillating even when all PID values are set to 0.(I was expecting this to act the same as when the wires were disconnected. The motor oscillates and drifts until i get a following error.
• Increasing the PID P gain to about 0.5 prevents the following error, but the oscillation is still present. 
  
  Does anyone have any suggestions on why the drive would be stable without the velocity command wires hooked up but unstable with them connected even with no movements?Any suggestions on where to start troubleshooting would be appreciated.
  

  File Attachment:

  File Name: AnalogConfig.hal
  File Size:9 KB

  File Attachment:

  File Name: AnalogConfig.ini
  File Size:3 KB