‘PairA'Topleftpinandbottomleftpin
‘PairB'Toprightandbottomright
NOTE:Ensurethesensorisconnectedtothecontrollerwithonepinfrom‘pairA'andonepinfrom‘pairB'.
Sensor resistance checks
A resistance check test is recommended:
During system installation once all sensor cabling has been completed
After every hardware change to the system (e.g. sensor, cable or switch change)
Every six months, after the system has been commissioned, to check for any sensor failure or cabling issues
Resistance check procedure
RegulatethetemperatureoftheCMMroomtoaconstanttemperaturebetween16°Cand28°C
Allow the CMM to stabilise thermally for a minimum of one hour
Measure the sensor resistance from the 37-way D-type socket that the sensors are wired into. This is the resistance that the UCC
measures (cable plus sensor resistance).
Allworkpieceandaxissensorresistancemeasurementsshouldbewithinthisrange;8.4kΩ<R<15.7kΩ
Best practise for using the thermal compensation system
Ensure the CMM is not subjected to unnecessary changes in temperature (fans blowing, close to radiator, in direct sunlight or any other
powerful radiant sources)
Excessive humidity should be avoided
Use the system as close as possible to the calibrated temperature
Renishaw recommends that workpiece and axis sensors are verified at six month intervals
Workpiece sensor
Ensure the workpiece sensor is in full contact with the workpiece
Aim to position the workpiece sensor in the middle of the workpiece or near where the measurement is taking place
Electrically ground workpiece prior to using the thermal effect compensation system to avoid electrostatic discharge (ESD) through the
workpiece sensor
Use multiple sensors for large workpieces
Handle the workpiece sensor by the white sleeve if possible or wait for five minutes once the sensor is in position before proceeding to
take a measurement
Keep the workpiece sensor cabling away from moving sections of the CMM
NOTE: It is not recommended to run axis thermal compensation without workpiece compensation (where axes and workpiece are at
the same temperature) as it is unlikely that reliable results will be obtained.