Honeywell 400 Series Hardware Manual page 95

In the operate, or normal, state the subsystem is engaged in punching cards or is actively
waiting for a command. In this state the punch can handle data in any of the three punching
modes described above. The current mode is determined by the instruction received.
The punch enters the standby state when it does. not receive a punch instruction within a
certain time and therea_re_fi'o existing'Attenti'on. ior Data Alert conditions. This interval
may be set for anywhere between 12 seconds to. 3 minutes and 42 seconds, depending on
the user's needs. When the specifiedperiod expires, the motors halt; however, power is not
cycled down. Lights on the Operator's control panel indicate the change in the subsystem's
state. The operator can manually return the punch to the operate state by pressing controls
on the subsystem operator's control panel. The subsystem automatically reverts from
standby to the operate state by receiving a punch instruction.
Checking
Reliability of the punch is guaranteed by a read-after-punch feature. This reading station
examines the parity of each punched row to determine if the correct number of holes
has actually been punched.
The following punch conditions are also checked:
Punch read or busy.
Attention --hopper empty, stacker full, feed alert, card jam, manual halt, chadbox
missing or full, or empty prepunch station.
Data Alert-~punch instruction or data not received in time, parity error, punch error.
Instruction rejected.
The processing system determines whether or not the punch is prOperly connected to it.
Timing Considerations
The CPZZOl punch may operate asynchronously or in synchronization with the processing
system. When operating in synchronization, the subsystem receives apunch instruction
and the associated data in time to punch a card during each feed cycle.
Each feed cycle is initiated by a feed signal from the controller and lasts for 200 milli-
seconds. During the first 174 milliseconds, a card is punched with data received during.
a previous feed cycle. When the card is punched, the Terminate signal indicates the end of
the operation to the processing system. There remains an interval of 26 milliseconds
between the Terminate signal and the next feed signal. To achieve and maintain the 300
cpm
speed of which this punch is capable, the next punch instruction must be received
during the first 6 milliseconds of this interval. All data associated with the next instruction
must be received before the end of the 26 -mi11isecond interval. a ,
-84-