| Problem | If | Possible cause | Because | Solutions | Resources |
| Joint 2 on limit switch error, when trying to power on the program | Z axis is down | Machine on limit | moved before homing, homing failed because of some other error, machine dropped slightly when turned off | Follow override limits sequence | |
| Z axis is not down | Damaged Z sensor | Z axis went too low under the limit | Raise Z axis manually and replace Z sensor |
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| Damaged Z sensor cable, or output card | Worn out cable, lack of maintenance | Inspect Z sensor, if replacing sensor does not work check cable 11.14 and output card 11D0 |
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| Z driver alarm when trying to move Z in override limits | Z axis stuck | Err-100 or Err-180 on servo drive | Check fuse 13FU12, Help Z axis move up by hand, check Z motor brake is functioning properly, check Z belt tightness and Z ball screw and rails conditions |
EPR electrical schematics PG13  |
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| Encoder cable error | Err-150 on servo drive | Replace encoder cable | |||
| Z axis does not move when holding Z+ | Z mechanical damage | Servo driver does not display r00 while holding Z+ | check Z belt tightness and Z ball screw and rails conditions, replace damaged components |
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| Z step signal problem | Servo driver display r00 while holding Z+ | Check output card 11D0 and ZPUL+ ZPUL- cables | |||
| Unable to override limit | Bad sensor or cable, EMP disturbance | Joint 2 on limit switch comes up as soon as program is powered on | Replace Z sensor, replace 11.14 cable, eliminate EMP disturbance, check grounding of the machine |
¶ Override limits
- Check override limits
- Power on program
- Clean error messages
- Hold the Z+ button till the red Z position is blue or reads >100
¶ Raise Z axis manually
Open top cover of Z axis
Use Allen wrench on the screws or between the screws to make leverage to turn pulleys clockwise to make the Z axis go UP
¶ Check Z motor brake
Press the IO on the software interface on and off
If you hear a clicking sound from the motor the brake is working properly (it is not very loud, you need to be close to the Z motor in a quiet environment to hear the click)
If you do NOT hear a clicking sound from the motor, open side cover
Inside you will find Z motor and it's cables, check again if you can hear the clicking sound with the cover open, if you cannot then check voltage on the brake cables (smaller plug with only 2 wires inside), with the machine on and IO on interface ON, there must be 24VDC between M and 13.121, if there is no voltage check fuse 13FU12 also have a look at EPR electrical schematics PG13, if there is voltage at the panel but not at plug then cable must be replaced, if there is no voltage in panel and at the plug of the motor either machine is off or some other electrical problem, if there is power on the plug motor should click unless cables inside the motor are damaged or brake inside the motor is damaged, open Z motor to inspect