StepperOnline A6 Servo

I don't use cia402 homing so someone else has to come with advice on that.
If you just want something that works you can use standard linuxcnc homing.
linuxcnc.org/docs/html/config/ini-homing.html

You can always revisit cia402 homing later on.
 

Er87.1 is "One-time excessive position reference increment". It sounds like your drives are trying to move from $home to the last commanded target position in one CSP period.

Try commanding the drive to find home using its CIA402 home method, and immediately (before the homing sequence finishes) set the target position to 0.

How can I adjust this?
I searched for this because it seems that other users had the same problem.
It was recommended to set the value HOME_ABSOLUTE_ENCODER = 2 and omit HOME_SEARCH_VEL; HOME_LATCH_VEL.
So I set the following.
HOME = 0.0                            
FERROR = 1000                        
MIN_FERROR = 1000            
MAX_VELOCITY = 100            
MAX_ACCELERATION = 750               
MIN_LIMIT = -1800                    
MAX_LIMIT = 100                        
HOME_OFFSET = 0.0
# Sequence for homing Start at 0                     
HOME_SEQUENCE = 0                     
HOME_SEARCH_VEL            = 1     
HOME_LATCH_VEL            = 1     
HOME_IGNORE_LIMITS        = YES
HOME_ABSOLUTE_ENCODER = 2
CIA402_HOMING_ENABLED = 1
CIA402_HOMING_METHOD=4
CIA402_HOMING_SEARCH_VELOCITY=100000
CIA402_HOMING_LATCH_VELOCITY=50000
CIA402_HOMING_ACCELERATION=131072

This now works for at least one axis, but all the others still malfunction.

 

Eureka!
I think I've found the cause.
While I was testing various settings in the ini file, the errors occurred sometimes on one axis and sometimes on another.  Even with unchanged settings, the error was sometimes there and then gone again. Until I turned off my handwheel (WHB04B). 
With the handwheel turned off, there are no problems with referencing. 
For some reason, the handwheel seems to interfere with the reference run. 
 

It's been almost a year since I originally started this thread and thought it might be of interest to give a status update on my machine.It's been humming along without issue powered by the A6 400watt AC ethercat servos.It is a 4x4 size router direct driven with ballscrews on all axis (XYYZ). I highly recommend the A6 servos for simple set-ups. Mine is not a demanding setup but for the cost, in my opinion they are an unbeatable value. Thank-you to those that gave me pointers when I was making the transition from step drive to ethercat!

 

Hi, that looks really good.
How stable is your system?
Have you ever had the problem where one of the Y-axes doesn't start moving during homing and the gantry is crooked?
That happens to me a lot. I have to restart the machine and then it works again.

I don't know what the problem is. It's always the left Y-axis that sporadically fails to start during homing. I always have to turn the machine off, and then it usually works. There haven't been any problems after homing so far. I can rule out wiring issues because I would get an error message.
I think that for some reason, the servo occasionally doesn't receive a start command for homing and therefore doesn't start.
The error must be somewhere in my configuration. 
 

Hi Andrax,
I am also currently in the middle of converting the previously working build to run with the absolute encoders so homing is only required once and I am somewhat experiencing the same issue as you. You said you fixed the sporadic jumps after homing by setting the homing_absolute_encoder parameter to 2 which i am trying out aswell. Sadly, the drive somehow doesnt start its usual homing scheme after the ER87 error (and the corresponding axis jump), it either doesnt do anything or its suuper slow. Did you also encounter this?

No, that wasn't the problem.
For me, it was the handwheel.
Do you have a similar device or something like that?

Then deactivate it.