Reference Mark Selector And Limit Magnet Installation - Renishaw QUANTiC RTLC40-S Installation Manual

Reference mark selector and limit magnet installation

IMPORTANT: Allow 24 hours after scale application before fitting magnets.
For accuracy and ease of positioning of reference mark selector and limit magnets,
the applicator tool should be used. The magnet should be attached
to the applicator tool as shown. Limit magnets can be positioned at any user
defined location along the scale, but the reference mark selector magnet should
be positioned adjacent to the selected IN-TRAC reference mark as shown.
As the QUANTiC readhead passes the reference mark selector magnet or limit
switch magnet, a force of up to 0.2 N is generated between the magnet and the
concentrators on the readhead. The design of the bracket should be sufficiently
stiff so that it is able to tolerate such force without distorting.
Following the clamping instructions on the scale installation will prevent this
magnetic force from disturbing the scale.
Limit trigger point
The limit output is nominally asserted when the readhead limit switch sensor
passes the limit magnet leading edge, but can trigger up to 3 mm before that edge
('RTLC40-S scale installation drawing', page
NOTES:
Reference and limit magnets may creep when influenced by magnetic materials in
u
close proximity. In such cases, they should be held in place using an additional fillet of
epoxy glue or similar along the outer edge of the magnet assembly.
Optional bolted reference and limit magnets are available
('RTLC40-S scale installation drawing', page
The reference mark selector and limit actuator locations are correct for the readhead
u
orientation shown.
The reference mark selector magnet is only required for 'Customer selectable reference
u
mark' readheads. For more information refer to QUANTiC series encoder system data
sheet (Renishaw part no. L-9517-9778).
External magnetic fields greater than 6 mT, in the vicinity of the readhead, may cause
u
false activation of the limit and reference sensors.
QUANTiC RTLC40-S installation guide
4).
4).
P limit magnet
Magnet applicator tool
Remove self-adhesive
backing paper
Selected IN-TRAC
reference mark
Q limit magnet
Reference mark
selector magnet
9