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I’ll dig through it for a bit this morning. It’s been a year since I did serious work on the machine; have to see if I’m forgetting something. I’m pretty sure it’s Modbus only. Machine was rewired a little over a year ago; it’s pretty clean and fresh if I do say so myself

VFD is not showing faults. I guess I’ll try running the spindle directly from the VFD panel. I hate that UI.

I realized I solved this problem, but never finished up this thread.  Parts of the solution might help someone else, so here goes.  It's a bit of a hack.  But a clean hack, as hacks go.  

To recap:  what I needed was the glue board(s) between the mill, the steppers, their drivers, and my Mesa card.  I'm not ready to switch to something like the TB6600 for the drivers, and even if I did, I'd still need mounting hardware, a new box, etc.  My shop is very small -- my mill basically fills the space it's in, up against a wall, tucked in between the workbench and some shelving.  No room for big new boxes.  Only small new boxes.

I searched for carrier boards which would hold multiple Polulu style driver modules, but came up empty.  Lots of carriers for just one, but none for four of them.  Seems odd, but I looked pretty hard.

What I ended up doing is leveraging the MKS router controller that came with the new mill.  It had the power distribution I needed, the sockets for the A4988 modules, headers that matched the stepper motor wiring, of course all of which I needed.  It also had the Atmel processor running Grbl, laser outputs, and some other stuff, which I didn't need.

And very conveniently, and unexpected, there is a header next to each Polulu socket which gives access to the step/dir/enable signals between the processor and each driver module.  I think these are probably there so that you could use the controller to drive external stepper drivers instead of the Polulus, but I realized that if I simply kept the processor in reset, it would be tri-stated, and I could instead use those headers as external inputs to the A4988 drivers.  In other words, I could use my existing controller as the "carrier" board I'd been looking for, with no modifications at all.  (The board has a header which makes the board reset signal available, normally connected e-stop.  I just jumpered it to ground.)

So that's what I did.  I have a (very small) box sitting next to the mill that contains the original mill controller (relocated -- it used to be mounted on the gantry), and the Mesa card.  The pre-made cables from the motors to the controller card were all long enough to reach the box, with no splicing.  (Yes, I know cardboard isn't optimum.  But getting it all working and enclosed came first.  I'll make a better box soon.)

 

I still needed a small interface board to make wiring the limit switches more tidy.  They're all too short to reach the Mesa directly.  At Adafruit, I found a small breakout board, intended for an RPi pico.  It's basically a bunch of screw terminals, .1" headers, and solderable grid, in a compact form factor, all for just $12.50:   www.adafruit.com/product/5907 .  That went into a small project box mounted on the gantry, and serves as the junction box where the limit switches, e-stop, and probe inputs all gather, and are wired in a bundle to the Mesa.  It gave me an organized place to join the +/- limit switches into single inputs, etc, but mostly it just a place to screw down wires in order to connect them together.

 

I know it wouldn't be everyone's design, but I'm happy with it for now, and it went together cleanly.

 

 

Thanks for responding Tommy.

As I mentioned the 24v power supply is holding steady at 24.1v. I've had my DVM connected for several hours without a single deviation, so I'm confident the PS is good. I've just sent the results of my findings to MESA tech support to get their input on the issues.

Maybe a wiring issue?

Transient electrical problem that came from or damaged the VFD?

Does the VFD have any connections to the 7I76 or is it entirely controlled by MODBUS?
 

scsmith1451 wrote:

I'm using a dedicated 24v switching power supply which is holding a constant 24.1 output. Setting the sserial_port_0=20xxxxxx and reading the fieldvoltage I'm seeing a constantly fluctuating value from 22.01 - 23.9 v

Get a good quality power supply, that is way to much fluctuation, MeanWell or Delta preferably.
Or an old used original laptop power supply, they work just fine for everything 24V, and have clean power. Do not buy e-bay or aliexpress laptop supplies they are terrible.

Hey!

We are working on an interesting project that requires a middle/senior developer with knowledge of 5 axis RTCP motion control.
Looking primarily for a freelancer, I will be happy to share more details in private. 

If you are interested please contact me on - 
WhatsApp or Telegram: +7 999 135 48 73

Thanks! 
Yury.

Hi Peter. Issue is with the rear end bearing, I changed those and now it is working fine. Thank you all for your support.

Thanks Peter. Was my 1st thought, but the with the spindle being the only thing not working, and all the VFD ctrl coming from the Modbus, it wasn’t obvious how this could be a culprit. I’d guessed it was some knock on effect fm when the spindle 1st quit.

FWIW, that error message only showed at the 1st event. After restarting, nothing complains.

I did check the analog inputs which are not connected. All are sitting at exactly 0v.

On a 5I25T, unless its completely corrupted, you should be able to recover
by moving jumper W5 up.

If you move W5 up and cycle the power, the red INIT light should blink
If it does, the card is recoverable with mesaflash. if not, a JTAG programmer
would be needed to recover.

Also for the 5I25T make sure that you use a current mesaflash.

Limit switches should never be hit so need to be outside the working area. If you use use shared home/limit switches, a home_offset in the inI file should be used to move the axis away from the limit switch during homing, Your home_offsets are set to 0

That does seem like a lot of ripple (nearly 2V)
that should not directly cause an issue but its
odd.

Probably the card should be returned for evaluation/repair/replacement

 One other clue might be to look at the analog input hal pins.
They should be very close to 0V with nothing connected.

The way the 7I76U digital inputs work is that they are read as
analog voltages and the threshold/hysteresis is set by the
field voltage. That's why I suspected a field voltage sensing issue.
 

I'm using a dedicated 24v switching power supply which is holding a constant 24.1 output. Setting the sserial_port_0=20xxxxxx and reading the fieldvoltage I'm seeing a constantly fluctuating value from 22.01 - 23.9 v

Aciera wrote:

For jogging there is the 'anglejog' component:
linuxcnc.org/docs/stable/html/man/man9/anglejog.9.html
 

Thank you, and this is what I love about LinuxCNC, it seems that whatever somewhat custom idea you dream up LinuxCNC has the handle to make it happen. It's a tinkerer's  candy store.

Hello,
can someone explain to me why I'm getting this error message:

Linear movement in line xx would exceed the positive stop of the Z axis.

Line xx contains "N330 G53 G0 Z0." This error message isn't always possible?
As far as I understand, the Z0 position can always be reached, since it's at the very top.

Thanks for your help.