Readhead Mounting And Alignment; Reference Mark Selector And Limit Magnet Installation - Renishaw T101 Installation Manual

Readhead mounting and alignment

s
Mounting bracket
The bracket must have a flat mounting surface and should provide adjustment to enable
conformance to the installation tolerances, allow adjustment to the rideheight of the readhead,
and be sufficiently stiff to prevent deflection or vibration of the readhead during operation.
Readhead set-up
Ensure that the scale, readhead optical window and mounting face are clean and free from
obstructions. To set nominal rideheight, place the Green readhead spacer with the aperture
under the optical centre of the readhead to allow normal LED function during set-up
procedure. Adjust the readhead to maximise the signal strength along the full axis of travel
to achieve a Green set-up LED on the readhead (>70% signal). If a digital Ti/TD interface is
used, aim for a Blue LED on the interface.
NOTE: The readhead should be installed and set-up with the AGC switched off
(CAL LED off). When re-installing, factory defaults should be restored.
Readhead set-up LED status
Green Orange Red
Pitch
0° ±1°
TONiC RSLM/RELM installation guide
Yaw
0° ±0.4°
Roll
0° ±0.5°
Green spacer
Rideheight
2.1 ± 0.15 mm

Reference mark selector and limit magnet installation

For accuracy and ease of positioning of reference mark selector and limit magnets, the applicator tool (A-9653-0201)
should be used. The magnet should be attached to the applicator tool as shown below.
Limit magnets can be positioned at any user defined location along the scale, but the reference mark selector magnet
(T1010 readhead only) should be positioned adjacent to the chosen IN-TRAC reference mark as shown below.
As the TONiC 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.
NOTE: Reference and limit magnets may creep when influenced by magnetic materials in close proximity.
In such cases, they should be held in place using an additional fillet of
epoxy glue or similar at each end of the magnet assembly.
P limit magnet
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.
Applicator tool
(A-9653-0201)
Remove
self-adhesive
backing paper
IN-TRAC reference mark
Q limit magnet
Correct position of
reference selector
for readhead
orientation shown
(Only required with
T1010 heads)
11