System Calibration (Cal); Step 1 - Incremental Signal Calibration; Step 2 - Reference Mark Phasing; Calibration Routine - Manual Exit - Renishaw ATOM Installation Manual

System calibration (CAL)

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:
Clean the disc and readhead optical window
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If reinstalling, restore factory defaults.
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Ensure AGC is switched off (readhead set-up LED is Green, Red or Orange).
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Maximise the signal strength for complete rotation around the disc. (readhead set-up LED is Green)
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NOTE: CAL routine maximum speed <100 mm/s.
Step 1 – Incremental signal calibration
Initiate calibration routine.
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No interface ACi interface Ri interface
Ground the Connect the CAL pads Press the CAL button
CAL pin for together or ground the on the side of the
interface for
<2 seconds remote CAL line (pin 8)
<2 seconds
for <2 seconds
using a
2 mm
allen key or
similar tool.
2 CAL
pads
WARNING! Activating the CAL
switch only requires 2.5 N force.
Applying excess force may
permanently damage the switch.
The readhead set-up LED will now periodically single-flash Blue to indicate that it is in the incremental
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signal calibration routine. The set-up signal (V
Rotate the readhead around the disc, ensuring you do not pass a reference mark, until the readhead
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set-up LED starts double-flashing Blue. This indicates the incremental signal is now calibrated and
the new settings are stored in the readhead memory. The set-up signal (V
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 Blue
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of the readhead set-up LED) the calibration of the incremental signals has failed. After ensuring failure
is not due to overspeed (>100 mm/s), exit the calibration routine, restore factory defaults and check the
readhead installation and system cleanliness before repeating the calibration routine.
ATOM
rotary installation guide
Ti interface
Press the CAL button
on the end of the
interface for
<2 seconds
CAL
using a
button
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.
) will be a nominal 0 V.
X
) will be a nominal 1.65 V.
X
Step 2 – Reference mark phasing
Rotate the readhead back and forth over the reference mark until the readhead set-up LED stops flashing
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and remains Green. The reference mark is now phased. The set-up signal (V
depending upon system set-up (see 'Interface output specifications' for more details).
The system automatically exits the CAL routine and is ready for operation.
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If the readhead set-up LED continues double-flashing Blue after passing the reference mark many times,
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it is not detecting the reference mark. Ensure that the readhead orientation and lateral offset are correct.
Calibration routine – manual exit
The calibration routine can be exited at any stage. Depending upon the interface used follow the relevant
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section in the table below to exit CAL mode.
No interface ACi interface
Ground the CAL pin for Connect the CAL pads
<2 seconds. together or ground the
remote CAL line (pin 8) for
<2 seconds.
On successful exit the readhead set-up LED will stop flashing Blue and remain Green or Red.
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Restoring factory defaults

When realigning the readhead, reinstalling the system, or in the case of continued calibration failure,
factory defaults should be restored.
To restore factory defaults:
Switch system off, then switch on again using the following methods depending on interface used.
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No interface ACi interface
Ground and hold the Connect the CAL pads
CAL pin whilst switching together or ground the
the system on. remote CAL line (pin 8)
whilst switching the
system on.
The readhead set-up LED will flash Blue four times on switch on.
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Release CAL button, CAL pads link or CAL pin ground.
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Check the 'Readhead mounting/installation' and recalibrate the system.
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NOTE: System must be recalibrated after restoring factory defaults.

Switching Automatic Gain Control (AGC) on or off

AGC can be switched on or off via the interface or the CAL line.
No interface ACi interface
Ground the CAL pin for Connect the CAL pads
>3 seconds then remove together or ground the
ground link remote CAL line (pin 8) for
>3 seconds then disconnect
The readhead set-up LED will be Green with the addition of Blue when AGC is active.
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NOTE: The system must be calibrated before switching AGC on.
) will be a nominal 3.3 V
X
Ri interface Ti interface
Press and hold the CAL Press the CAL button on
button on the side of the the end of the interface for
interface for <2 seconds. <2 seconds.
Ri interface Ti interface
Press and hold the CAL Press and hold the
button on the side of the CAL button on the end
interface whilst switching of the interface whilst
the system on switching the system on
Ri interface Ti interface
Press and hold the CAL Press and hold the CAL
button on the side of the button on the end of the
interface for >3 seconds interface for >3 seconds
then release then release
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