Emcoturn 120 lathe retrofit

OK thanx, I have the AD one coming, hooefully with only 1 VFD it will not have com errors. I likely wont be polling it for any info either but you never know.

I am using one of the $2 ones from eBay. Seems to work fine.

However, I think that there is an error in your understanding:

I don't see any other way than relays for the 7i76e outputs as they do not switch the common on the VFD, they supply external voltage

This is true for the general-purpose IO outputs, but there are two special outputs for VFD:

SPINDLE ISOLATED OUTPUTS
The 7I76E provides 2 isolated outputs for use for spindle direction control, and
spindle enable. These outputs are OPTO coupler Darlington transistors. They are all
isolated from one another so can be used for pull up or pull-down individually. They will
switch a maximum of 50 mA at 0 to 100 VDC. The SPINENA output is special as it uses
the same signal that enables the analog output. When the analog output is enabled, the
SPINENA OPTO output is on.

These two outputs are effectively simple (if polarised) switches.

thanx Andy. I thought I had asked that question and understood the 7i76e provided voltage which is not allowed. Can you tell me which ports act as a switch instead of a signal? I assume its these? So It would be right to connect the spindle direction and enable using the DCM and the D11 and D12 pins directly through the 7i76e?

LutzTD wrote: I assume its these?

Yes. It will depend on the VFD whether the on/off and fwd/rev terminals need to be connected to VFD V+ or GND, but those terminals can do either.

OK, that makes sense, here is the setting to make them run/stop fwd/rev

Looks like DCM is "Digital common" which will be 0V.

So, connect ENA+ to DI1 and ENA- to DCM and connect DIR+ to DI2 and DIR- to DCM.