Rockwell Automation 2706-F11J_F11JC_F21J_F21JC DL50 INSTALLATION MANUAL User Manual

Page 74

Chapter 6

Slave Mode Operation / Examples

6–10

Updating Embedded Variables from a DL20 or DL40

Use the following guidelines when updating embedded variable data in DL50
messages from a DL20 or DL40 Dataliner.

•

For a DL20, update variables using a sequencer to strobe the high and low
bytes of each variable as well as the message number (as described in
DL20 User Manual). A baud rate of 9600 is recommended.

•

For a DL40, a baud rate of 9600 is recommended. You may update
variable data sent to the DL40 as frequently as the PLC scan permits, but
you must have the DL40’s message wait time set for more than 1 second.
With a 1 second wait time, you may set the DL40 auto repeat attribute to
YES.

Note: DO NOT set the DL40 wait time to 0 and the auto repeat attribute to
YES for any messages sent to the DL50 by either the DL20 or DL40.

IMPORTANT:
If you are using a DL20 or DL40 to send messages to a DL50 at a baud rate
of 19.2K, we suggest that the updates of embedded variable data be sent in
intervals longer than the typical program scan times. You can accomplish this
by using the logic program (next page) in a PLC-5: