IBM Selectric - Page 179

Cl N/O POINT
Figure 30.10
BOUNCING Cl N/O POINT
Figure 30.11
Figure 30.12
Scope: C2 o/p
Ref: Power Supply Common
Time Base: 10 ms/div
Vent Amp: 5 volt/em with lOX attenuated probe
Shown
is the scope pattern seen on C2 operating point when
Selectric I/O is attached to OLSA. This is a normal signal
reflecting inductive spikes generated by a LSA relays. These
spikes
do not originate in the Selectric I/O.
I 30.1
Refer to Figure 30.4
I 30.2
5-35
Magnet Seal Time
C5 N/C opens at 55° converted to ms
Total
8.0 ms
19.7 ms
27.7 ms <
27.7 ms is total of everything but mechanical delay.
Therefore -- Total Pulse Length =
Subtracting Seal Time + C5 N/C Time
Will equal the mechanical delay
37.0 ms
-27.7 ms
-~;;S
9.3 ms is within Machine Specifications (14 ms
maximum)
Refer to Figure
30.5
Magnet Seal Time
C5 N/C opens at 55° converted to ms
Total
6.5 ms
19.7 ms
26.2 ms
26.2 ms is total of everything but mechanical delay.
Therefore -- T ota I Pu Ise Length
Subtracting Seal Time + C5 N/C Time
Will
equal the mechanical delay
42.5 ms
-26.2ms
16.3 ms'
16.3 ms is in excess of Machine Specifications (14
ms maximum)
Why
is 9.3 ms okay but 16.3 ms excessive? If this
printer were to be run in an open ended application,
the closure of C5 N/C would signify that the printer
is ready for another character. The C5 N/C contacts
on this printer close at 130° or 46.5 ms after cycle
starts.
Figure 30.4
Normal Mechanical Delay
Magnet Seal Time
00 to 130
0
Total of
9.3 ms
8.0 ms
46.5 ms
63.8 ms
Thi s pri nter, then, wou Id be ab Ie to accept the next
character in 63.8 ms or for this one cycle at better
than the 15.5 character rate.