Preparation of Punched Tape
The
punched tape as per standard code represents program characters on 8 tracks. BCD
system specifies the numerals 0 through 9 on first 4 tracks. A series, of
feeding /driving timing holes, is provided between third and fourth track. The
series extends through the length of the tape and is used to engage with the
teeth of sprocket, which transmits the tape.
Errors are likely in punched tapes; to detect the error the code prescribes either ODD number of holes or EVEN number of holes for each character. EIA code specifies odd number of holes while ISO code and ASCII code specify even number of holes. A parity check circuit is incorporated into MCU, to ensure specified number of holes is always present for each character punched in the tape.
In a
8-track system there can be 128 combinations of holes.
In EIA
system holes in 5th track are meant for odd parity check.
Zero is represented by a hole in sixth track.
End of block is represented by a hole in eighth track.
In ISO system, 8th track is reserved for even parity check. Zero is represented by holes punched at 5th and 6th tracks.
Part
Print to NC Tape:
Need of Process Planning: In conventional manufacturing, the information from the production drawing is taken by the operator on the shop floor. In case of NC manufacturing, this information has to be properly arranged to prepare instructions for the machine, in necessary order. Thus process planning is essential. The planning sheet should give details about tool used, operations to be performed, speeds, feeds etc.
EIA ISO