Retrofitting a 3-axis VMC with DC servos - guidance needed

The 7I84U needs its own power supply.

You must supply VFIELDA and VFIELDB (Usually the same)
These set the output voltage and the input thresholds.
Normally VIN comes from VFIELDB (W1 LEFT=default)

 VFIELDA and VFIELDB are supplied via the ORANGE connector (TB1)
on the 7I84U.

There is a small 5V supply needed for the 7I84Us isolated serial interface
This comes from the RJ-45 connector, and in turn from either the 7I74 or
7I97TA.

 

Thanks, I understand it now. I have 1 more question.

Today I'm connecting the encoders and limit switches, but I have a question about the drive enables.

My machine has relays for the drive enables. Is it a good choice to keep those? 'Cause the 7i97T has optocoupled drive enables, but I don't know if it's a problem for the control or the board. I have to verify if the coil uses less than 50mA or buy new ones.

But is it good practice to have an extra layer of protection, or is it better to operate them directly?

You can drive small relays with the enable OPTOs
but make sure that the relay coils have flyback diodes.

I am working through retroftting a motionmaster. I kept all my relays. My goal was slightly different, I wanted to keep the wiring as stock as possible because there was a chance of the whole upgrade not working and I would want to sell it stock, but I think I'm far along enough that its worth more as a linuxcnc box now.

I'm having some trouble with the servo enable relays.My relays have flyback diodes, but the datasheet is giving me a headache. The coil draws 40mA, but the flyback module includes an LED with no specified current draw. Since I can't be sure of the total load, I'm guessing I can't use it.Would you guys just change the module for these specific commands, or is there a better workaround?

These are the Finder 55 Series

i think its better to use other relays for these ones like interface relays isnt?

If it takes all this just to run the enable signal, I'm thinking it's better to wire it directly to the drive. Is there any good reason to keep it isolated with an extra relay? The 7i97T outputs are already opto-isolated, and my servo drive has a 10kΩ input impedance anyway. Adding a relay isn't really worth it, right?