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If your concern is about the notchyness of the 2nd set of sign waves. I think your G64 settings are eating your lunch and your high tolerance setting is causing the naive cam detction (Q tolerance which defaults equal the P tolerance) to screw up your motion. Changing from G64P0.01 to G64P0.001 makes a big difference in the smoothness of 2nd set of sign waves and the motion ends up much closer to what your g-code was programmed to be.

 

I have been of the opinion that the current default motion planner has never been completely bug free since the circular arc blending/multi line look ahead was added back in version 2.7. I have often observed quirky behavior for series of moves similar to those you have posted. But the "new" planner offers such a significant improvement in milling speed for most cad/cam generated code as to justify tolerating it's issues.

​​​​​​​But I'm not noticing any differences between runs on my machine simulation

Have you tried running RS485 through this module? I just can't seem to get it to work.

Has this issue been resolved yet? Or has no one looked into it?

Hi, I am new to the forum, I built a 4 x 4 cnc plasma table 6 years or so ago, I used Mach 3 with cheap Chinese BOB's. I have not used the machine for a number of years, but now wanting to get it up and running again using Linux CNC. 
My question is where can I purchase a Mesa 7i96 or 7i96s board? preferably from a UK supplier.

The servomotor uses the ECAC XP200 driver, and according to the manual, the digital inputs can only be controlled with 24V.

I also have the ground for the 7i92 tied to the common ground.

Now the question becomes:
will the servo drive work with 5V on the inputs?
Did you check the manual?
Older drives do not, but all new-ish ones do.
-
Now i wonder if i missed how old is your drive!

Sorry, i missed 5V/24V thing above.
I edited the above posts.

The Isolator is doing 5V to 24V translation so unless the BOB has a relay/24V output
it cannot go directly to the VFD

Sounds like maybe  grounding issue (or damaged OPTO)

Note that a parallel port ground is nearly always frame ground
but the 7I92 ground may be floating
 

Deleted as i missed the part about level shifting.
Sorry.

PCW wrote:

I would check the output of the direction control PC817 with a voltmeter/ohmmeter

I checked for continuity between the V output and GND using a multimeter, and even though the LED is lit, there is no continuity. 


Tomorrow I’ll check the resistance at the output. It’s all very strange because I have two brand-new modules, and they behave the same way. 

They always worked perfectly on a parallel port, but I no longer have the PC with a parallel port to test them again...

I would check the output of the direction control PC817 with a voltmeter/ohmmeter

What do you recommend I use instead?

Deleted as i missed the 5V to 24V level shifting mentioned above.

ok this is driving me crazy. today i fired up the machine, turned on the spindle, hit reverse... and it worked. first time since swapping to the 7i92.

i thought maybe the gremlins had left, so i shut down the machine, powered it back up again, tried reverse — nothing. spindle just keeps going forward. led on the module still lights up, wiring is solid and untouched. literally didn't touch a single wire between the time it worked and the time it stopped.

any clue what could cause this?