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Alarm output
The REF interface asserts the alarm output (E) for the following conditions:-
Incremental signal level below 20%
Incremental signal level above 135%
Readhead speed in excess of specification
Signal offset compensation of sine and cosine excessive
Signal balance compensation excessive
System installation/calibration
The calibration procedure is required to optimise the gain, balance and offset of the analogue input
signals in the REF interface. These settings are then stored and recalled for initial use at startup.
To calibrate the system, the following sequence should be carried out:
Prior to calibration, AGC should be off. To switch AGC on or off, the CALIBRATE button should
u
be pressed for more than 3 seconds. When AGC is on, the CAL/AGC LED will be on and when
AGC is off, the CAL/AGC LED will be off.
Install the readhead according to the instructions in the 'Readhead mounting and alignment' section.
u
Enter the calibration routine by pressing the CALIBRATE button momentarily. The calibration routine
u
is indicated by slow flashing of the CAL/AGC LED.
Traverse the readhead slowly past the scale until the CAL/AGC LED stops flashing. The calibration
u
cycle is now complete.
If calibration fails, the CAL/AGC LED will flash quickly instead of switching off. If this happens the
CALIBRATE button should be pressed momentarily to exit the calibration routine. The calibration procedure
should then be re-tried.
If the unit continues to fail calibration, factory default settings should be restored by powering down, then
pressing the CALIBRATE button as power is re-applied. The calibration procedure should then be repeated.
NOTE: To exit the calibration routine at any time, the CALIBRATE button should be pressed momentarily.
If fitted, the reference mark should be phased (see reference mark set-up)
RGH25F RGS20 installation guide
Reference mark set-up
To ensure unidirectional repeatability, the reference mark requires phasing with the scale in the direction
of normal datuming operation.
A reference pulse is output in both directions, but repeatabilty is guaranteed only in the
phased direction.
Ensure readhead is set up correctly with a green LED indication over the full length of travel and that
the reference mark actuator is fitted correctly.
NOTE: It is recommended that a datum procedure is performed as part of any power-up sequence to
ensure the correct datum position is recorded.
NOTE: Reference mark output is synchronised with the incremental channels, giving unit of resolution
pulse width.
Phasing procedure
The readhead must be moved over the reference mark in the direction to be used for the datuming
operation. The reference mark is phased correctly when the set-up LED flashes red for 0.25 seconds.
If it flashes orange or goes blank, the reference mark adjuster screw should be turned anti-clockwise
1 8
by
turn and the procedure repeated until a red flash is obtained.
Red Orange Blank
SET UP LED colour at
reference mark position only.
NOTE: Reference mark flashes only
occur up to 100 mm/s traverse speed.
Limit switch
A limit switch signal is output when the readhead sensor passes over the magnetic actuator.
NOTE: RGH25F readheads are available with reference mark or limit switch detection.
Select output at order.
1 8
turn
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