Scalar 218
Theory of Operation
adic
Service Procedure
63-1181-01 Rev A
4
Micro-Stepper Processor
The
Micro-Stepper Processor
takes high level movement commands and breaks them down into finite
steps of the X Stepper Motor. The four finite motor steps, are displayed on the four diagnostic LED’s.
The four digital steps are broken down further into 16 sub-steps. These sub-steps are of variable
amplitudes such that the resultant waveform of a full step approximates a sine wave. The
Micro-
Stepper Processor
controls the following:
l
Quad output D to A converter.
l
Four diagnostic LED’s.
l
Data input and output registers.
Door Open Stepper Motors
Each drive assembly employs a door over the drive cartridge opening. This door must be physically opened
or closed to load or unload a cartridge. Damage to the drive and/or media will occur if the door is opened
or closed while the drive is still loaded (the tape is still wound through the read/write head mechanism). To
prevent damage to the drive and media, the drive illuminates an Operate Handle LED on its front panel to
indicate when it is unloaded (the tape is fully rewound into the cartridge). When the Operate Handle LED
is illuminated the drive assembly outputs an “OK to Open Door” status message via its serial port.
To automate the insertion and removal of cartridges the 218 employs a
Door Open Stepper Motor
that
rotates the door’s hinge shaft, thus opening or closing the door. This
Door Open Stepper Motor
is
mounted on the drive assembly’s drive mounting plate directly above the drive. The
Controller Section
monitors each of the drive assembly’s serial port, via the Drive Mux Bus, and opens or closes the door
when the “OK to Open Door” status message appears.
