Index homing Mesa 7i96s

Hi

I also could use some index inputs for my Emco lathe. Is it possible to make a firmware for 7i96S with 2 index inputs in isolated I/O?

Its possible, but would need slow index inputs (at least 300 usec or so in duration)
what does you index signal come from?

From inductive sensors, measuring from ballscrew pulley. Should be slow enough I think.

7I96S firmware with stepgen indexes 0,1,2 on isolated inputs 8,9,10

I figured 3 index inputs would be more generally useful and if you
just want 2 (0,1) indexes and need all 9 remaining isolated inputs
you can use  gpio.010 instead of inm.010




Note that there is standard firmware (7i96s_sdid.bin) that has all 5
stepgen index inputs on the P1 expansion connector (but these are just
unprotected 5V TTL inputs)

 

Could you check if this is correct firmware? I'm not getting anything to stepgen pins (hm2_7i96s.0.stepgen.00.index-enable) but pin hm2_7i96s.0.gpio.008.in goes true when indexing. Or is there something I'm missing?

hm2_7i96s.0.stepgen.xx.index-enable does not reflect the index input
but rather must be set true by LinuxCNC when LinuxCNC wants to search
for an index signal. When it has been set true, the index hardware is armed
and when an index is detected, two things happen:

1. The stepgen position is zeroed
2. hm2_7i96s.0.stepgen.xx.index-enable is set false

The reason index logic works this way is so the (possibly very short) index pulse
is captured by high speed hardware and the hardware signals LinuxCNC that the
index has been detected.

For index homing to work, you must connect hm2_7i96s.0.stepgen.xx.index-enable
to joint.x.index-enable (and also the PID components index enable input)
Also index homing must be enabled in the ini file.

I suspect pncconf does most of this index setup but does not connect the
hm2_7i96s.0.stepgen.xx.index-enable to the per joint index-enable signals.

...

routerman22 wrote:

Hi, im wondering how to add index homing signals to the pncconf so i can do index homing. I cant seem to find the option to add the signal to the right io i put on the mesa 7i96s in pncconf.

I have 4 inputs. Index pulse x,y,y1,z axis. Can see the status. But dont seem to find the actual io option in needs to be to be recognized by pncconf as an index signal. What am i missing? 
if it needs to be a "full on" encoder in the 7i96s config... it only has 1 of those.

thank you,
routerman22
 

Hi Routerman,
Just in case you see this, since I just pulled the trigger on some Mesa cards (maybe not the correct ones...), did you ever get this to work?

I have Delta B2s so one step down from yours, but for index pulse, I think they work exactly the same.

Actually, and I don't want to get your hopes or those of anyone else reading this in the future, the B3 may be able to home internally to its index pulse... I a, pretty sure the A series can, but I feel like there's a chance that it's one of the things the B3 can do over B2. So, a signal would be sent from the controller to the servo drive and the drive would take over homing and it would report back once done.

[EDIT]
Homing To The Index/Z Pulse of Delta Servos - and Important Differences Between A and B series!

I am new at all this so could be wrong, but just had a look at the B3 manual and I am almost certain they can home "internally", meaning the servo drive handles the homing. Which might save the Mesa from the noise and speed issues Peter talked about earlier in this thread. So, it would work like this: The Mesa would send a signal to the servo drive to start homing and the drive would be configured to go look for the limit switch and then from there go in either direction to its index pulse whereafter it would send a signal to the Mesa, that homing was complete.
I think you can set up offsets, too - so, hit the index, then go to an offset, then signal Mesa. 
Sounds like a cleaner or at least potential alternative way to do this? 

Sadly, I don't have B3s but the "lowly" B2s which can't do this... 

I would assume the A-series, both A2 and A3 can do it as the A series are above the B series, but please look into that yourself if you are in the market for these and need this feature. 

PCW wrote:

File Attachment:

File Name: 7i96sd_esdid.zip
File Size:250 KB

Hi Peter, 
I am the one who just ordered the 7i96s and 7i84u and talked about needing to read four index pulses. 
Is this the FW, I would need to make it work?

All best and thanks for the guiding on email, too,
David 
 

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