LA Series Linear Servo Amplifier Technical Reference Manual
37
Appendix A. Serial Communication Messages
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.
