Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 515)

PAL
Chapter 9B
Integrating Your Teach Pendant
9B-4
To send a command that the PAL program can receive, you send a packet
with 60 hex in the command (CMD) field. The teach pendant and PAL
programmers define the values in the special data (SD) and DATA fields
and map those values to a teach pendant function.
You can use the SD1, SD2, and SD3 fields for requests that require
minimal data. The SD1 field is seen as an integer in PAL, but when it is
received from PAL, it contains only the least significant byte of the PAL
flag. SD2 and SD3 are stored as a single integer to PAL, with SD2 being
the most significant byte and SD3 the least significant byte. You can send a
maximum of 7 integers to PAL in the DATA field.
For example, let’s say that the programmer has defined the SD fields as:
Field Definition
SD1 Request Type: Jog (1), Home (2), or Data (3)
SD2 Axis Number: 1 through 9
SD3 Motion Type: Absolute (1) or Incremental (2)
A keystroke combination defining Incremental Jog for Axis 6 would then
send this command to PAL when pressed:
CMD SD1 SD2 SD3 TNS TNS DATA
DLE STX 60 01 06 02 05 02
[position]
DLE ETX BCC
When the CNC receives the message, the teach interface software
acknowledges the message by sending a DLE ACK (DF1 protocol) to the
pendant. The interface software checks PAL’s message input buffers to see
if they are clear.
If they are clear, the interface software moves the message into the buffers
and sets the PAL flag $TPRECV. PAL must decode the message to jog axis
6 incrementally according to the position information in the DATA field.
The PAL programmer decides if PAL responds with a message back to the
teach pendant.
If the buffers are not clear, the interface software sets the Input Buffer
Overflow flag, $TPOFLOW, but does not send a message back to the teach
pendant. PAL would have to notify the teach pendant of the overflow by
initiating a transmission if the pendant needs to take action.
9B.4
Sending Commands to PAL
(CMD=60 hex)