Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 445)

Section 8
Communication Interface
8-12
Binary data such as AMP and PAL images do not have eighth bit parity
bits attached to them. Because binary files such as AMP and PAL can
contain data which correspond to RS-491 Level 2 control characters, these
files cannot be output to Level 2 devices. The control characters could halt
or otherwise affect the file transfer. The Level 2 tape reader interface on
the 9/Series is capable of reading binary files.
A man readable file name is punched to the tape by the 9/Series at the
beginning of all files. This is done for all types of devices except the
Generic Level 2 device which doesn’t output the man-readable header.
Care should be taken when transmitting files to the control which contain
man-readable headers. Sometimes this part of the tape can contain Level 2
control characters which may halt or other wise affect the file transfer.
Table 8.E
Control Code Functions
Control Code Function Description
DC1 Start Xmission This code is used to begin data transmission from a
peripheral to the control. It is also used to restart
data transmission which had been interrupted by
the DC3 code output from the peripheral or the
control.
DC2 Restart This code is used to begin data transmission from
the control to a peripheral.
DC3 Stop Xmission This code is used to stop data transmission from
the transmitting device. It is output from the data
receiving device.
DC4 Ignore The device receiving this code ignores any received
data until it receives the DC2 code after the data
has been transmitted from the control to the
peripheral.
EOT End of Transmission This code is used to notify the completion of data
transmission.
DLE Data Link Escape This code is used to abort the transmission.
Important: For the EOT code, M02 or M30 is usually used.