beautypg.com

Servo card (ssv) – Exabyte EXB-8505 8mm User Manual

Page 29

background image

The drum rotates constantly at 1831 rpm in the default format (8500c
format for the EXB-8505 and EXB-8505XL; 8200c format for the
EXB-8205 and EXB-8205XL). This speed of rotation results in a
nominal effective head-to-tape speed of approximately 150.5 inches
per second (3.8 meters per second). Approximate tape movement is
0.5 inches per second (11.1 millimeters per second). Forces acting on
the tape and various component mechanisms are correspondingly
low, resulting in long life for both the media and tape transport
mechanism.

Note:

In 8200 format, the drum rotates at 1923 rpm.

Servo Card (SSV)

The Servo (SSV) card contains the tape drive’s servo circuits,
including two digital LSIs and one analog LSI, a dedicated
6303-compatible microprocessor, and a 64-KByte FEPROM.

The Servo card controls all the mechanics of the tape drive, such as
the following:

Tape transport mechanism

Adjustment of tape velocity based on track-embedded servo
information

Drum, reel, and capstan servos

Circuits that control the reel motor, the load motor, the drum and
capstan motors, and the front load motor

Sensor interface circuits for the drum, reel, and capstan,
tachometers

Sensor interface circuits for the load and mode states

Sensor interface circuits for detecting physical beginning of tape
(PBOT), physical end of tape (PEOT), tape length and type, and
write protect and cartridge load states

May 1994

EXB-8205 and EXB-8505

1-15

(Standard and XL)

1 Features