Qualstar RLS-8350, Technical & Service Manual

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2-4 Description and Theory of Operation
511010 Rev. 07-01-19
2.2 General Description
Models accommodate one or five tape drives (three for the RLS-8350) and have re-
movable storage matrices for tape cartridge storage. There are presently four models
that utilize LTO tape technology. All units operate on internationally available AC
power. Brushless motors are used exclusively. All digital closed-loop servo systems
use magnetic and optical position sensors. The servos automatically calibrate them-
selves, thus eliminating all electrical adjustments. Preventive maintenance is re-
duced to replacing the air filter, when so prompted by the library and removing debris
inside the RLS.
2.2.1 Motion Systems
•
The RLS utilizes a four-axis robotic cartridge handling mechanism that
moves cartridges between the storage slots and the tape drives. In the un-
likely event this assembly ever needs replacing, it can be accomplished in
less than 5-minutes.
All axes are driven by brushless DC motors. The motors move the linear
axes with precision lead screws driven by long-life timing belts. Feedback
is provided by hall effect sensors with optical end-of-travel sensing. Car-
tridge gripping is accomplished using a solenoid for simplicity and de-
pendability. The linear axes are riding on linear ball bearings, and the ro-
tating axis is supported on ball bearings. This results in high reliability,
long life, and nearly zero maintenance for the robotics.
2.2.2 Sensors
Optoelectronic Interrupters Sensors
These consist of an LED emitter and an optoelectronic sensor, which produces a digi-
tal output indicating if the light from the corresponding LED is blocked or not. Some
consist of two loose parts, and others have both parts integrated into one housing.
•
Z Home Sensor
This sensor pair is mounted on the Z-axis controller board. A feature on
the carriage interrupts this sensor pair when the carriage is moved all the
way back closest to the tape drives.
• Y Home Sensor
This sensor is mounted on the Y-Theta controller board. A feature on the
picker-head interrupts this sensor when the picker-head is moved all the
way down to the lowest extent of its travel.
• Rho Home Sensor
This sensor is mounted on the Carriage controller board. A feature on the
gripper axis interrupts this sensor pair when the gripper is moved all the
way back in the retracted position.