Fault
finding
Examining the MCU LCD display, status LED’s, the system configuration and current conditions, can
solve many problems.
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 is connected to the UCC should have been set up in the configuration file.
• The joystick should be 'enabled'.
• The MCU ‘joystick enable’ button must be pushed.
• 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 override 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 joystick speeds and accelerations that are set in the UCC configuration file, are correct.
• 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 max speed is set to a high value, the machine may be able to exceed the maximum
move speed to cause an overspeed error.
• If the joystick max fast acceleration is set to too high a value, 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: it is an entry in the UCC
configuration file.
necessary to accomodate electro-mechanical tolerences in the joystick assembly, these settings
are not user configurable.
NOTE: As with most cable connected ancillary equipment, it is the actual cable that 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 an examination of the cable.
Page 29 of 31
MCU1, MCUlite-2 and MCU5 user's guide
02/01/2013
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