Card Reader Event Times (Model 7122) - Xerox 7120 Reference Manual

Time (in milliseconds) Event
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
--,---.-------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 operational
II
and an "unusual end" will be signaled to the controlling system.
--I---lr----------Column 1 arrives at read station. Mode change (EBCDIC to binary) will occur at this time if
rows 1 and 2 are punched.
-t-~------
Column 80 arrives at read station.
--I--~®
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.
....... , - - - - - - - - N e w feed cycle enabled at this time if new valid order present and reader still in "automatic"
mode.
Notes:
®
Feed cycle is approximately 27 ms if card feeds on first attempt, approximately 87 ms if card feeds on
second attempt, and approximately 147 ms if card feeds on third attempt. If a card has not been fed after
three attempts, the transport motor will halt, the reader will switch to "not operational", the FEED
indicator will light, and an "unusual end" will be signaled to the controlling system.
®
©
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The data bytes are transmitted, with respect to the column read time (approximately 1.12 ms), as shown below.
1-1.12 ms-I-98 ms-I
Data available to controlling system
~
1
U
t
U
EBCDIC mode: Transmit one byte
for each column
~~-----,n~_---,nL----_
-----'n~_----Jr1Jl
nL----_
Binary mode: Transmit rows 12-5 _ _ _ _ . . . . . . .
f
I
f
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 125 ms later if card jams in throat area, causing transport motor to halt, FEED
indicator to light, reader to switch to "not operational
II ,
and an "unusual end" to be signaled to the
controlling system.
Read and timing jam detection occurs 125 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" will be signaled to the controlling system.
Stacker jam detection occurs 125ms later if card jams in stacker area. Results in same action as
©
above.
Figure 6. Card Reader Event Times (Model 7122)
14 Programming Considerations