Index homing Mesa 7i96s

Index (Z pulse) Homing on Delta Servos 

I hope it's OK I add a bit more info to this thread specifically in regards to Delta servos. I bought some used ones quite cheaply. To me, it's a better deal than the no name ones as the Deltas have much better documentation and a proper tuning/setup software. (Actually, I am almost sure at least some of Automation Direct's servo series are rebranded Deltas, too.)

Earlier in the thread PCW mentioned a potential speed issue where the Mesa input may not be fast enough to read the index signal unless the index is somehow slowed down. But perhaps the following tidbit I found will help with this (it's from a different controller manufacturer describing  how to wire up index homing  ):

For proper operation it is necessary to rearrange DELTA drives default settings. Number of pulses of drives’ output encoder – should be shifted to a lower value to ensure adequate INDEX signal pulse length. P1-46 parameter set by default on 2500 pulses – set on 500 pulses per rev or less. This change has no influence on servo drives working precision because their internal procedures work on encoder full accuracy anyway.

PCW also suggested on email that I slow down the homing speed (home to regular limit/home switch can be faster, but then slow down the home to index/Z pulse after that). So, maybe a combination of lowering the pulse value for the encoder and slowing down the home speed a bit is the ticket.

Again, if you have B3s, A2s or perhaps A3s(?) you can try making the servo drives handle the homing routine. 

PCW wrote:

Yes, this firmware should work (though would need to be modified to add the fourth axis index input)

Great, thanks.
4th is in the future, no need for it for a while:)

 

PCW wrote:

Yes, this firmware should work (though would need to be modified to add the fourth axis index input)

Hi Peter, 
My boards arrived a while back and now, finding some time to dive into this - my first ever - Lcnc install. To recap, I have a 7i96s and the new 7i84u but I am looking to use the servos index pulse for homing. Now, the question is, is there a FW which has both the daughterboard plus the index pulse functionality included? Or would I have to somehow add the 7i84u manually and how would I go about that?

If by daughtercard you mean the 7I84U, any firmware with a sserial port will do.

(basically and 7I96S firmware that does not use the serial expansion for modbus etc)

PCW wrote:

If by daughtercard you mean the 7I84U, any firmware with a sserial port will do.

(basically and 7I96S firmware that does not use the serial expansion for modbus etc)

Yep, the 7I84U would be the daughtercard to the 7I96s. 
OK, I will try making it work with the FW you linked above.
As an aside, I have it downloaded already but have a bit of an issue making it show up in MesaCT even though I think it's in the right folder, but that's probably just me still overseeing something - will read some more posts and/or try mesaflash in the terminal. 

PCW wrote:

If by daughtercard you mean the 7I84U, any firmware with a sserial port will do.

(basically and 7I96S firmware that does not use the serial expansion for modbus etc)

Sorry for being daft, but I reflashed the board with the FW you uploaded here. So far so good, but just checking - does this FW have the serial port feature, so I can connect to the 7I84U without having do download anything else for any of the two boards?