Delta Printer Z-Probe not looking right

Hi all,

I've been away for a while but I now have a set of FSRs mounted with the FSR Endstop Controller.

I've got everything setup I think but here's exactly what I'm running.

Kossel Mini
Ramps 1.4
J-head Hotend
FSR/FSR Endstop Controller from TriDPrinting
Repetier 0.91 Rev 8 Firmware
Repetier-Host V1.0.6

To clear any questions about the machine not being setup correctly, this printer has been running for months without FSRs and I just wanted to add them to increase first layer precision.  I can confirm that no motors are skipping, the printer is calibrated completely, and the print surface is not THAT far out of skew.

So here's where I'm at:

I verified that the probe is working correctly with G31 and can measure the distance with G30.

When I run a G29 on the three points this is what I see:
12:52:49.224 : Z-probe:15.00 X:0.00 Y:60.00
12:52:50.458 : Z-probe:28.11 X:-50.00 Y:-27.00
12:52:52.223 : Z-probe:28.18 X:50.00 Y:-27.00
12:52:52.755 : Z-probe average height:23.76

In EEPROM Settings I have Z-probe height = 15.000, Max. z-probe - bed dist. = 0.000.

Why does the first probe show 15, but the other two probings show 28.11 and 28.18 and how does this affect the plane that is being created with the 3 probings?  I know that this would generate a very skewed plane, but does repetier not care about that offset?

I also tried setting EEPROM to Z-probe height = 0.000, Max. z-probe - bed dist. = 0.000 and got the following from a G29 command.

20:13:49.254 : Z-probe:0.00 X:0.00 Y:60.00
20:13:50.478 : Z-probe:12.92 X:-50.00 Y:-27.00
20:13:52.260 : Z-probe:13.76 X:50.00 Y:-27.00
20:13:52.817 : Z-probe average height:8.89


  • Please do not set Max. z-probe - bed dist. = 0.000. That would prevent probe going up so it would keep triggering making results definitely wrong.

    Z-probe height = 0.000 is also not good. This i sthe distance between triggering probe and nozzle hitting bed, which is normally a positive number.
  • I understand that the Maz. z-probe - bed dist. = 0.000 should be different.  I will adjust that to a positive number.

    Z-probe height = 0.000, though, I thought needed to be 0.000.  I am using FSRs and the nozzle is actually hitting the bed to trigger.  

    What should these values be then, approximately?

  • Oh i thought FSR was inductive measurement, Thats the problem with short codes in foreign languages:-) Of course z probe height is 0 or nearly zero depending on bending/flexing until sensor triggers. But you should still release pressure before retesting again, so Max. z-probe - bed dist.  > 0 and ther eis also a value for retesting that should be > 0.
  • If I set the Z-Probe height to 15.000, then the first measurement shows 15.  Why do the other measurements show 28.11 and 28.18? Is there something in the EEPROM that I have set incorrectly?

  • edited December 2014
    I'm having the same issue, was this ever resolved?

  • Just saw Firmware 0.91. Please try 0.92 which has changes some probing code. That's also what I use since 0.91 is not developed any more.
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