[EspressoE]

I have a Faunc 0-MD Mill (Lilian CNC 400) that was just starting a milling cycle and during the G53 Z0., the Z-axis halted suddenly and an alarm 339 Alarm for the Z-Axis SPC was generated. I power cycled the mill, but when I home the Z-axis, it decelerates when the limit switch dog is hit (as it should) and then slowly continues past Z=0.000 and then eventually generates the 530 Z+ over-travel alarm when it travels over the dog -- it seems like the homing signal for Z=0 has been lost.

I checked the encoder cable and the connector was a few threads loose, so I tightened it, power cycled, and still have the same problem.

The 760-762 parameters are all 1000 0100, so the SRFLG (serial pulse coder connected) and the BZAL (do zero reference return) request is set which seems to indicate that all is normal. Parameters 770-772 are all 0 indicating no faults.

This system has the semi-closed loop servos (Model Alpha C6/2000; Part: A06B-0126-B077) which uses the serial pulse coder and type-B axis controller (serial pulse coder connects to the servo amplifier over JF3) and there is just one cable (JS3A) to the axis controller (AXE).

I'll double check the servo tuning screens in the morning and see if I can make sense of the reference position adjustment (section 5.3 of the 61395 maintenance manual), but would really appreciate any insights that people may have!

Thanks,
Eric

Same alarm for different axis in case people are searching for this: 319 (X-axis), 329 (Y-axis), 339 (Z-axis)

[Shottie_gp]

Im not sure if youve tried this yet .... press P and cancel at the same time while powering up the control.
Then zero return .
See if that helps you .

[EspressoE]

I haven't tried P + Cancel during power-on since I understood that just disables the soft-overtravel alarm on power-up and just applies to absolute encoders. This machine doesn't have absolute encoders and after power-on, I only get the soft over-travel when the machine really does over-travel. It makes me think that there is a missing homing signal, but the homing dog appears to be working. I check the schematic on that and see if anything makes sense.

If I don't find anything else, I will give P + Cancel a try just to cover all bases. . .

-Eric

[Shottie_gp]

Ok . Im not too sure what encoders ive got but i do know they are the red cap motors and im pretty sure its an ALPHA series encoder .
Good luck and hope you get it sorted .

[EspressoE]

I have the red-cap motors as well. I cleaned up the connectors and still had the same problem and then gave your P + Cancel on boot-up a try, re-homed, and now everything is fine! Turns out it only needed to go another 0.001 mm to properly home

Thanks for the suggestion since from everything I read, this wasn't going to work with my setup so I had already dismissed it!

-Eric