Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 513)

Chapter 9B
Integrating Your Teach Pendant
9B-2
The teach pendant needs to communicate in DF1 protocol. DF1 is a
communication protocol developed by Allen-Bradley that is used by the
Data Highway networks. For more information on DF1 protocol, refer to
the Data Highway/Data Highway Plus Protocol and Command Set Manual,
publication 1770-6.5.16.
All requests and information are sent in DF1 packets. The packets are
structured like this:
DLE STX CMD SD1 SD2 SD3 TNS TNS DATA DLE ETX BCC
Field Description Size in Bytes
DLE STX Start of Message 2
CMD Command field. Determined by CNC or the teach pendant. 1
SD1, SD2, SD3 Special Data 1, 2, and 3. Use for command modifiers or to include data for
CMD.
3
TNS TNS Transaction Number chosen by DF1 driver.
PAL cannot access this data for packets its sends or receives.
Two packets sent or received in sequence cannot have the same number.
If the CNC detects duplicate numbers, it eliminates the packet(s) after the first
instance of the number.
This field resets to 0 when you turn on power to the CNC.
You need to program your teach pendant to perform checks for duplicate
numbers, and to fill this field to satisfy the CNC.
2
DATA Some commands will have a field that contains additional command data.
The same type of data that can be put into the special data fields, including
commands, can be programmed here as well.
0 -- 14
DLE ETX End of Message 2
BCC Block Checksum 2
Four types of commands can be sent or received with the teach pendant
interface. Some are pre-defined by the teach interface software. Others are
defined by the teach pendant and/or PAL programmer.
9B.2
Using DF1 Protocol
9B.3
Programming the Teach
Pendant to Send and
Receive Messages