Rockwell Automation 2706-F11J_F11JC_F21J_F21JC DL50 INSTALLATION MANUAL - Manual (Page 57)

Chapter 5
Serial Communications
5–7
Clearing Lines of Text
There are two methods of clearing text on the display:
•
You can either send a message packet with a control byte (field 1) that has
a Ctrl-C (decimal 3) value, or
•
You can send a message packet with the following format:
Slave Address
Field 1
1 Byte
Line Number
Field 2
1 Byte
Carriage Return
Field 3
1 Byte
The line number in the message packet specifies which line(s) to clear:
ASCII Character Decimal Value Function
Ctrl-A 1 Clear line 1.
Ctrl-B 2 Clear line 2.
2 50 Clear all lines.
Performance
The DL50 display requires a time delay between successive packets sent
from the host (master) to the DL50 display. This delay is referred to as the
“inter-packet delay”. It is required so the DL50 can process the received data
properly before the next packet is received.
These delays need to be programmed into the host system only if messages
will be sent in rapid succession to the same display. The time delay interval
required is a function of the display type, character size, baud rate, and
packet length. Table 5.F lists the required delay times for DL50 displays
operating in Simplex Protocol mode, using the worst case scenario.
Table 5.F
Simplex Protocol Inter-Packet Delay Requirements
19200 Baud with Large Characters (worst case)
Display Type Packet Length Delay (milliseconds)
2706-F11J 250 characters 300 mS
2706-F11JC 250 characters 350 mS
2706-F21J 250 characters 300 mS
2706-F21JC 250 characters 350 mS
Note: Typical inter-packet delay requirements for most applications range
from 80 to 250 milliseconds.
Simplex Protocol (continued)