USER MANUAL

Chapter 8
Special Functions
8–21
Selecting a Master Address
The addressable master option allows you to connect up to 32 DL20s on a
single RS-422 network (up to 100 with inline repeaters). You can trigger
messages at one or all of the DL20s by sending a master address with the
message number. Refer to Chapter 5 for a description of addressable master
protocol.
The prompt for setting a MASTER ADDRESS looks like this:
SET MASTER ADDR? N
If you answer Yes to this prompt, the DL20 will display:
MASTER ADDRESS: 0
You can now enter the master address. Some values are illegal addresses,
Table 8.D lists them:
Table 8.D
Illegal Master Addresses
Decimal Hex ASCII Character
4 04 EOT (CTRL D)
6 06 ACK (CTRL F)
7 07 BEL (CTRL G)
13 0D CR
18 12 DC2 (CTRL R)
20 14 DC4 (CTRL T)
22 16 SYN (CTRL V)
43 2B +
45 2D -
48 through 57 30 through 39 0 through 9
A master address of 0 disables the master address feature.
Note: Address 127 is recognized by all masters, regardless of the master
address. Use this a convenient means of triggering a message to all master
displays.
Note: A master address can also be selected using the Addressing Bar
(Catalog No. 2706-NF1) at the parallel port. This method does not require a
keyboard or terminal and is useful if you are downloading messages from a
tape. The Addressing Bar can only be used if communication to the display
is through the serial port.