9b.4 sending commands to pal (cmd=60 hex) – Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set User 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

[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)