Mesa 7i76 / 6i25 setup question

Im setting up my mesa plug and go kit and i cant figure out how the power supply arrangement works.

If i set the jumpers to use the computers 5v supply, is that used to power the 5v outputs for the step and direction outputs as well or is that just used for communication purposes between the 7i76 and the 6i25.

or

does the 24v field power supply get reduced to 5v to power the step and direction outputs?

Ive used other components in the past that needed more current to run the motor encoders and i dont want that issue to happen again.

Thanks

The 5V supply and Field power are independent, you need to provide both

7I76's 5V power draw is low enough that its usually fine to power the 7I76 from the
FPGA card

Thanks for the info, I went ahead and set the cards up for 5v from the computer and it works fine but I dont have anything thats drawing any current hooked up yet....

Unless you have something very unusual like an spindle encoder that draws 500 mA
or some such, you should be OK with powering the 7I76 5V from the FPGA card.

Thanks for the info. im going to be using 4 encoders on this project, 3 for individual axis handwheels and 1 for the spindle. from what i gather by scouring the internet is that using 4 encoders will not be abl to use the 5v supply from the computer so im going to change to an external power supply.

Is there a 5v bus for a 5v external supply on the 7i76 or will i need to run seperate +5v and grounds to each encoder input.

Ive currently running the 7i76 board in mode 2 so i have 2 encoder inputs available and a spindle encoder available.....7i73 here I come...

You are probably still OK unless your MPGs draw a lot of power
You can always verify that the FPGA 5V is OK by reading the 5V at the 7I76

Is there a 5v bus for a 5v external supply on the 7i76 or will i need to run seperate +5v and grounds to each encoder input.

I have a new 7i73 on the way and id like to reduce the chance of having an issue by using an external power supply for both the 7i76 and the 7i73

5V on the 7I76 (from whatever source) is routed to the encoder, step/dir, and RS-422 port connectors

Thanks again for the help, makes things so much easier when you can get confirmation on your thoughts before things turn to smoke and landfill candidates.......