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MCU fault finding

Many operating problems can be solved by checking the MCU status LEDs, the system configuration and current operating conditions.

NOTE: As with most cable connected ancillary equipment, the actual cable is the most vulnerable part, particularly with a joystick where it can be trapped by the part under inspection, pulled if caught by machine motion, trodden on, run over, etc. If any malfunction with the MCU occurs, the first step should be to examine the cable.

Suspect operation of joystick or buttons

There is a comprehensive test program for the MCU joystick operation and button function within UCCassist-2. Plese refer to the UCCassist-2 user's guide (Renishaw part number H-1000-5224) for details.

The joystick will not move the CMM

Several conditions have to be satisfied before joystick controlled moves can be made:

  • The joystick must be connected to the UCC and have been set up in the configuration file
  • The joystick must be 'enabled'
  • The MCU ‘joystick enable' button must be pressed down
  • The axis locks must not be applied
  • The CMM application software must be in manual (joystick) mode
  • The probe must not be ‘deflected', unless probe disable is on
  • No limit switches should be open, unless disabled
  • The CMM position must be inside all ‘soft limits' if these are enabled

The speeds are too low or too high

  • Check the correctness of the joystick speeds and accelerations that are set in the UCC configuration file
  • Check the operation of the fast / slow switch - higher speeds will be obtained when this switch is active

The motors disengage during joystick operation

  • If the joystick maximum speed is set to a high value, the machine may be able to exceed the maximum move speed and may cause an overspeed error
  • If the joystick maximum acceleration is set too high, the motor signals may attempt to exceed the overdrive limits and cause an overdrive fault
  • If the system proportional gains are set too high, or the velocity gains are too low, an overdrive fault may occur

Speed override does not work correctly

  • This feature must be enabled separately from the general joystick enabling function. It is an entry in the UCC configuration file

NOTE: Speed override ONLY works on DCC moves and scanning. It is not operational when the MCU is in manual (joystick) mode.

Servos will not engage

  • E-STOP not connected correctly
  • E-STOP still asserted
  • An outer limit switch is activated

No screen display

  • Check cable connection