17
TONiC RESM20 angle encoder system installation guide
System calibration
Calibration is an essential operation that completes readhead set-up, with the optimum incremental and
reference mark signal settings stored in the readhead’s non-volatile memory.
Before system calibration:
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Clean the scale and readhead optical window (contamination around the reference mark may
result in reference mark dephasing).
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If re-installing restore factory defaults.
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Ensure signal strength has been optimised over the full axis of rotation; the readhead LED will
be Green.
NOTE:
CAL routine maximum speed < 100 mm/s (all Ti/TD interface models).
TD interface can be calibrated in either resolution.
Step 1 – Incremental signal calibration
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Ensure Automatic Gain Control is switched off (CAL LED on readhead is not illuminated) before
beginning calibration
(‘Enabling / disabling AGC’, page 18)
.
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Press and release the CAL button on the end of the interface using a 2 mm allen key or similar tool.
WARNING!
Activating the CAL switch only requires 2.5 N force. Applying excess force may
permanently damage the switch.
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The CAL LED will now periodically single-flash to indicate that it is in incremental signal
calibration mode.
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R
otate the axis at slow speed (< 100 mm/s or less than the readhead maximum speed,
whichever is slowest), ensuring the readhead does not pass a reference mark, until the CAL
LED starts double-flashing. This indicates that the incremental signals are now calibrated and
the new settings are stored in the readhead memory.
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The system is now ready for reference mark phasing.
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For systems without reference mark, go to ‘Calibration routine - manual exit’
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If the system does not automatically enter the reference mark phasing stage (no double-flashing
of the CAL LED) the calibration of the incremental signals has failed. After ensuring failure is not
due to overspeed (> 100 mm/s
or exceeding the readhead maximum speed), exit the calibration
routine, restore factory defaults
(‘Restoring factory defaults’, page 18)
and check the readhead
installation and system cleanliness before repeating the calibration routine.
CAL LED
Settings stored
Single flashing
None, restore factory defaults and recalibrate
Double flashing
Incremental only
Off (auto-complete)
Incremental and reference mark
Step 2 – Reference mark phasing
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Move the readhead back and forth over the selected reference mark until the CAL LED stops
flashing and remains off. The reference mark is now phased.
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The system automatically exits the CAL routine and is ready for operation.
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If the CAL LED continues double-flashing after passing the chosen reference mark many times, it
is not detecting the reference mark. Ensure that the correct readhead configuration is being used.
Readheads can either output all reference marks or only output a reference mark where a reference
selector magnet is fitted.
Calibration routine – manual exit
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To exit the calibration routine at any stage press the CAL button. The CAL button will then
stop flashing.