Xerox 7120 - Card Reader Event Times

~~
/~----
Time (in milliseconds)
Event
o
16
Card reader receives valid read order and reader is in "busy automatic" state. Light check occurs
--.------- at this time. If light check fails, the read indicator will light, the reader will switch to "not op-
erational" and an "unusual end" will be signaled to the controlling system.
50
4
"'7-j_+-1- _____ Column 1 arrives at read station. Mode change (EBCDIC to binary) will occur at this time if rows
1
and 2 are punched.
60
70
80
90
100
110
210
220
230
240
_..L- ______ Column 80 arrives at read station.
End of card is detected; card reader signals "channel end" to controlling system. Card reader
returns to "ready" condition (a new SIO can be accepted if no interrupt is pending) unless the con-
troll ing system specifies command chaining, in which case the reader requests a new read order.
250 ---®-- New feed cycle enabled at this time ifnewvalid order present and readerstill in "automatic" mode.
Notes: ® Feed cycle is usually approximately 47 ms but can be as long as 200 ms (in case of slippage or slight jam).
If a card has not been fed after 200 msec, the transport motor wi II halt, the reader wi II switch to "not op-
erational", the FEED indicator will light, and an "unusual end" will be signaled to the controlling system.
® The data bytes are transmitted, with respect to the column read time (approximately 2.05 ms), as shown
below.
l-- 2. 05 ms ---J-- 160 ms--l
Data available to controlling system
Col. 1 ~
t t
EBCDIC mode:
Transmit one byte n n n
for each col umn -.-11 ______ -' L ______ -' '- ___ _
~ llil nJl_
Binary mode:
Transmit rows
12-5 ~ 1 L
©
@
®
®
Store rows 6-9 Transmit rows 2-9
Transmit rows 12-1 plus
rows
6-9 of previous column
t indicates data overrun will occur at this time if data is not accepted by controlling system.
Throat jam
detection occurs 215 ms later if card jams in throat area, causing transport motor to halt, FEED
indicator to light, reader to switch to "not operational", and an "unusual end" to be signaled to contror-
ling system.
Read and timing jam
detection occurs 225 ms later if card jams in read and timing area. Results in same
action as © above.
Dark check occurs at this time. If dark check fails, the READ indicator will light, the reader will switch to
"not operational", and an "unusual end" wi \I be signal ed to the controll ing system.
Stacker jam detection occurs 215 ms later if card jams in stacker area. Results in same action as © above.
Figure 5. Card Reader Event Times (Model 7121)
Programming
Considerations 13
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