IBM 6580 User Manual

+ACCESS 0
+ACCESS I
~
ACCESS
DEGATE
LOGIC
+24 VDC
»
Figure 7-17. Stepping Signals
Two signals, access 0 and access 1,
activate the stepper motor. Thesetwo
signals are sent through an Access
Degate logic block (Figure 7-17)
through an AND (A) block where they
are combined, then through an amplifi-
er to increase the signal before going
to the motor control line. At this
point, motor control line becomes an
electrical detent. The stepper motor
armature will turn 1.8 to align with
the detent made in the winding. The
stepper motor will remain in this
detented position until the system
electronics signal the access lines
again.
The next access ~ignal through the
access degate logic selects stepper
motor line 1 (Figure 7-18). The
stepper motor armature turns another
1.8 to the next track. The access
lines remain active holding the motor
and head carriage in this track until
the next signal is received on the
access lines to step the head either
forward or back.
+_A_CC_E_SS_O __ ~) >-------------------1
_+A_CC_E_SS_I ____ ~)~ __ -- __ -- ____ --~
ACCESS
DEGATE
LOGIC
STEPPER
MOTOR MC 0 YELLOW
STEPPER
STEPPER
MOTOR
MOTOR
MC I RED
STEPPER
MOTOR MC 2 ORANGE
STEPPER
MOTOR MC 3 BLUE
STEPPER
MOTOR COMMON BLACK
)
Fifteen separate step signals are
needed to move the head carriage
assembly from track 50 to track 65.
The signals step the head carriage
through a four condition sequence and
repeat the sequence until fifteen
steps have been completed
(Figure 7-19).
Seven step signals are needed to move
the read/write head from track 61 back
to track 54.
If the system electronics cannot
determine the track position, it
recovers by sending 77 reverse step
signals. This ensures the read/write
head returns to track 00. A pin
located in the stepper pulley stops
against the casting to physically stop
the read/write head at track 00. When
the system electronics completes the
77 step signals, it will start a new
count sequence by reading an address
field on track 00.
STEPPER
MOTOR MC 0 YELLOW
STEPPER
MOTOR MC I RED
STEPPER
MOTOR MC 2 ORANGE
~-----------------<~------------------~~
STEPPER
MOTOR Me 3 BLUE
STEPPER
STEPPER
MOTOR
+_2_4_V_DC ______ ~»~------------------------------------------------~) r-M_O_TO_R_CO_M_MO_N_B_LA_C_K ________ ~
Figure 7-18. Stepping Signals
7-18 IBM Displaywriter Product Support Manual

IBM 6580 Specifications

General

Brand	IBM
Model	6580
Category	Desktop
Language	English