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.

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
 

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?

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?

@susan-parker,
very nice, that should come in handy for your project!