Extron Electronics DDS 100 - Manual (Page 28)

RS-232 Programmer’s Guide, cont’d
DDS 100 RS-232 Programmer’s Guide 4-2
Host to DDS Communications
The DDS 100 accepts SIS™ (Simple Instruction Set™) commands
through the RS-232 port. SIS commands consist of one or more
characters per command field. They do not require any special
characters to begin or end the command character sequence. Each scaler
response to an SIS command ends with a carriage return and a line feed
(CR/LF = ), which signals the end of the response character string. (A
string is one or more characters.)
DDS-initiated messages
When a local event occurs, such as a front panel operation, the DDS 100
responds by sending a message to the host. The DDS-initiated messages
are listed below (underlined).
(C) COPYRIGHT 1999, EXTRON ELECTRONICS, DDS 100, Vx.xx
The copyright message is initiated by the DDS 100 when it is first
powered on. Vx.xx is the firmware version number.
RECONFIG
The Reconfig message is initiated by the DDS 100 when the resolution of
the input signal is changed and when exiting the front panel LCD
menus, which indicates that there may have been a change to the
adjustments or parameters.
The scaler does not expect a response from the host but, for example, the
host program might want to request a new status.
DDS error response
When the DDS 100 receives an SIS command and determines that it is
valid, it performs the command and sends a response back to the host
device. If the DDS 100 is unable to perform the command because the
command is invalid or contains invalid parameters, the DDS 100 returns
an error response to the host. The error response codes are:
E09 — Invalid function number (too large)
E10 — Invalid command
E13 — Invalid value (out of range)
Using the command/response table
The command/response table is shown on the following page. Lower
case characters are acceptable in the command field only where
indicated. Symbols are used throughout the table to represent variables
in the command/response fields. Symbol definitions are shown at the
beginning of the table, as is an ASCII-to-hexadecimal (HEX) conversion
table. Command and response examples are shown throughout the
table.
RS-232 Programmer’s Guide