IBM Selectric - Oscilloscope Interpretations; Sel.ectric I;O Specifications. 28.0; Selectric I;O Modes of Operation

28.0 SELECTRIC I/O SPECIFICATIONS
28.1 Magnets and Solenoids
Component
Maxim'um
Pick Time
Keyboard Lock
Solenoid
Ribbon Shift Magnet
All Other Magnets
28.2 Clutch Operating Speed
55 ms.
12 ms.
10 ms.
Mechanism
Max. Mechanical Delay
Print Cycle Clutch
Operational Cycle Clutch
Shift Clutch
29.0 Selectric I/O Modes of Operation
29. 1 Closed Loop
10 ms.
14 ms.
7 ms.
Character rate is under control of I/O feedback sig-
nals. A character wi II not be sent to the I/O unti I
feedback contacts have sig na lied that the prev i ous
cycle is almost complete and the printer is ready for
another character.
29.2 Open Ended
I n the open ended mode of operati on, the character
rate is fixed, independent of I/O feedback signais.
This rate is usually set at 14.8 characters per second,
or a character every 67 .5 ms.
The
Selectric I/O has the capabi lity of running wide
open, at the rate of 15.5 characters per second, or a
character every 64.5 ms. This 3 mi IIi second differ-
ence is the safety factor allowed in the event of a
slow printer cycle.
30.0 OSCILLOSCOPE INTERPRETATIONS
The fo lIowing osci IIoscope trace pi ctures wi II cover
every area of the Selectric I/O Printer. Wherever
scopi ng is necessary refer to these photos for compar-
ative ana lysis.
5·32
PRINT MAGNET R2A (ONE ARMATURE PICKED)
Figure 30.0
Scope:
Mag Common
R2A Test Jack
5 ms/cm
o LSA Function: Print Space
Ref. Ti It & Rotate: T3/ R+3
Time Base:
Vert Amp:
Sync:
2 volt/cm
+ Int
Time from start of pick to C2 N/C opens
Magnet seal time
C2 N/C opens at 35
0
=
Total Mechanical Delay
6.0 ms
12.5 ms
PRINT MAGNET R2A (ALL ARMATURES PICKED)
Figure 30.1
25.0 ms
18.5 ms
6.5 ms
Scope: Mag Common
R2A Test Jack
5 ms/cm
o LSA Function: Print Space
Ref.
Ti It & Rotate: TO R-5
Time Base:
Vert Amp:
Sync:
2 volt/cm
+ Int
Time from start of pick to C2 N/C opens
Magnet seal time
C2 N/C opens at 35
0
=
Total Mechanical Delay
5.0 ms
12.5 ms
26.0 ms
17.5 ms
8.5 ms