Rockwell Automation 2706-F11J_F11JC_F21J_F21JC DL50 INSTALLATION MANUAL - Manual (Page 59)

Chapter 5
Serial Communications
5–9
A control byte containing Ctrl-L (decimal 12) indicates that the DL50 is
being initialized for the bootstrap mode. In this mode the DL50 will be idle,
waiting for the host to transmit a firmware update (refer to Chapter 7).
Field 2: ASCII Text or Special Control Characters
This field contains the ASCII characters (up to250) that are tobe displayed by
the DL50 or sent to the message buffer. The special control characters are
described on page 5Ć11.
Field 3: Slave Address
The slave address is a single byte field that can be any value from 1 to 255,
except for addresses
6, 13, 16, and 18.
A display with an address of 255 will accept all message packets regardless
of the address. In addition, any message packet with an address of 255 will
be received by all displays.
Note: Displays and messages with an address of 255 will not have a
response packet. This is to prevent multiple devices from trying to
transmit simultaneously on a half-duplex RS-485 network.
Field 4: Line Number
The line number performs one of two functions.
•
Indicates where text is displayed.
•
Indicates which lines to clear. Refer to the following table:
Line Number
Field 4
(Decimal)
Function
1 Clear line 1 or display text on line 1.
2 Clear line 2 or display text on line 2.
3 Reserved for future use.
4 Reserved for future use.
50 Clear all lines.
Note: The line number and other attributes as defined in the Message
Attributes byte (field 6) determine how the message is displayed.
Field 5: Carriage Return
This is a Ctrl M (decimal 13) character.
Duplex Protocol (continued)