X-Carriage; X-Axis Interconnect Pwa; X-Axis Confirmation Sensor; Y-Axis Motor - Sun Microsystems Enterprise Tape Library 7/3500 Field Service Manual

X-Carriage

The x-carriage is a structure that rides on the lower horizontal rail, provides and
mounts for the vertical rail. The x-carriage also mounts the y-axis motor, and mounts
the x-carriage interconnect PWA.

X-Axis Interconnect PWA

The x-axis interconnect PWA is located on the rear of the x-carriage assembly as
viewed from the left side of the system. The x-carriage interconnect PWA provides
an attachment point and strain relief for the x-umbilical. Signals from the x-axis
confirmation sensor and drive for the y-axis motor are delivered to the x-axis
interconnect through the x-umbilical.
The x-axis interconnect PWA receives a signal from the x-axis confirmation sensor,
buffers and drives it down the x-umbilical to the actuator driver were it is received
at the robotics controller. The x-axis interconnect PWA acts as an distribution/
interconnection point for the y-axis motor from the actuator driver through the
y-umbilical cable.
X-Axis Confirmation Sensor
The x-axis confirmation sensor is located on the x-carriage assembly. The sensor
confirms bin and tape drive column position to the robotics controller PWA. The
sensor enables the horizontal axis to home using slots in the x-axis sensor rail
mounted on the bottom of the library frame.

Y-Axis Motor

The y-axis motor, mounted in the x-carriage assembly, is a two-phase stepper motor
which has 1.8 degrees (0.005 inches) per step resolution. One end of the motor shaft
holds a flanged pulley that engages the vertical drive belt. The opposite end is an
idler pulley. The y-axis motor is micro-stepped to provide accurate open loop
position control. The position loop is closed through the y-axis confirmation sensor
and flags.
The vertical drive belt, an open-ended belt (not a continuous loop), is driven by the
y-axis motor to propel the vertical carriage up and down the vertical rails. The y-axis
is held at each position, without the need for a counterweight, by the stepper motor.
14 Sun Enterprise Tape Library 7/3500 Field Service Manual • July 1997