User guide

LA Stand-Alone Product User Guide

Revision A7

Page 32

6 Appendix A – Serial Interface Details

This section describes the details of the serial communication messages. The only white space character

used in this protocol is the Space (ASCII 0x20). All lines are terminated with a Carriage Return and Line

Feed (cr/lf) followed by a “>” prompt (ASCII 0x3E). The prompt is sent following any message by the

amplifier. The prompt line has no termination in order to allow a dumb terminal cursor to remain on the

prompt line. This provides a clear indication for the user when the amplifier is ready for a new command

when using a dump terminal interface.

Some common characters used in this section are:

cr = Carriage Return, ASCII 0x0D

lf = Line Feed, ASCII 0x0A

> = Greater Sign (used as the prompt), ASCII 0x3E

When the amplifier is first powered up, the user must wait until the sign on message and the prompt are

sent before normal communication can begin. The sending of the first prompt from the amplifier means it

is ready for operation. If a fault alarm is present on power up, the fault message will be shown followed by

a prompt.

All command sent to the unit must be in upper-case characters. Messages that the amplifier sends for a

particular command or condition are a fixed length. Messages are padded with the space (ASCII 0x20) to

achieve the desired length. As an example, all alarm messages are 14 characters in length.

All messages from the amplifier are shown in quotes to allow the programmer to determine the character

count for each message. The quotes are not part of the message. Any blank lines sent by the amplifier

are shown by the cr/lf sequence in the text shown below.

6.1 Sign on Message

Upon power up or following a reset, the amplifier sends the following message.

“>”

In addition, if any faults are present, the fault status is show following the above message.

“Alarm = BUS UV”

“>”