7i76e question Stepper Error

Hi
I use only 4 steppers and no mpg.

I wonder if I can use the unused 2x2 mpg inputs on TB5 as 5v return signal from my stepper drivers.
Adressing them via ....input-16 to ....-19 should be good?

And is there a way to use the 5V outputs of the 5'th stepper as f.x. enable signal?
And how to adress them in hal?

That would allow me to stay in 5v level in my "power" block.

Thx for your response

I won't respond regarding the technical capabilities but from what I've seen, those that have attempted to use 5v for their signals end up rewiring to use 24 volt field power due to noise and unreliable signals when 24V just pushes through any noise.

You are really wasting the capabilities of your 7i76e by not using field I/O.

I know its tempting to retain existing relay boards etc but in reality, they are obsolete with a 7i76e and you will have a more robust machine if you revise your machine wiring and eliminate the external boards.

Hi Rode
I'm very aware of all your arguments whitch are basicaly ok, but:

Stepper drivers are driven from 7i76e with 5v, no choice!
So going to the same device with a second voltage level ist naturally possible, but ist in my eyes not too clever. Yes, i can do by putting additional resistors in and will do if I have no other choise. I prefere same level on device f.x. for troubleshooting.
Mike

You can use the 5th axis step/dir signal as 5V enable signals if you like, you need to:

1. Enable only 4 stepgens (this frees the GPIO pins that drive the step5/dir5 pins)
2. Find the GPIO pins that match the stepgen5 step/dir signals
mesaflash --device 7i76e --readhmid
or
mesaflash --device 7i76e --addr 10.10.10.10 --readhmid
can help here
3. Set the GPIO pins into output mode ( set the is_output attribute for the stepgen5 GPIO pins )
man hostmot2 can help here
4. Chose the output pin (from the stepgen + or - pins) that disables the drive at startup

Thx PCW
Learned a new thing that makes sense for me:

I understood that i can go via hal gpio pin-signals for any in- and outputs signals.
So i can search and use the stepper-outs and the mpg-ins as i wan't.

Thx a lot again.

No, only direct FPGA pins (like the stepgen pins) can be accessed via GPIO
The 7I76Es field I/O cannot be accessed via GPIO nor can field inputs be use for 5V sensing
unless you have 5V field power

Ok, Last question. Can i read the four MPG pins?
Thx

Yes, the 7I76E MPG pins are readable as normal field inputs
(with normal field input thresholds of about 1/2 field voltage)

Mike_Eitel wrote:

Hi Rode
I'm very aware of all your arguments whitch are basicaly ok, but:

Stepper drivers are driven from 7i76e with 5v, no choice!

To enable my stepper drivers (well actually disable them), I added a 24 volt relay that switched 5 volt (stolen from one of the stepgens)
that is chained to all of the enable inputs on the stepper drivers. ( I use all 5 stepgens)