4 – 10
Remote Operation
4.3
Introduction
Remote operation of the LDC500 is through a simple command lan-
guage documented in this chapter. Both set and query forms of most
commands are supported, allowing the user complete control of the
controller from a remote computer, through the GPIB, RS-232, or
ethernet interface.
Where applicable, the corresponding front-panel interface to each
command is also indicated.
4.3.1
Interface configuration
All three remote interfaces have configuration settings that may need
adjusting from the front panel. These are accessed from the [Util]
menu.
The factory default settings for the RS-232 interface are 9600 baud
with no parity and no flow control. The GPIB bus address defaults
to 2. The IP address, netmask, and default gateway all must be
configured (either from the front panel, or RS-232 or GPIB) prior to
ethernet operation.
Most instrument settings are retained in non-volatile memory. Upon
power-on, these settings are restored to their values before the power
was turned o
ff
.
Where appropriate, the default or power-on value for parameters is
listed in
boldface
in the command descriptions.
4.3.2
Buffers
The LDC500 stores incoming bytes from the remote interfaces in
separate 64-byte input bu
ff
ers. Characters accumulate in the input
bu
ff
er until a command terminator (
CR
,
LF
, or GPIB-EOI signal)
is received, at which point the message is parsed and enqueued
for execution. Query responses from the LDC500 are bu
ff
ered in
interface-specific 256-byte output queues.
If an input bu
ff
er overflows, then all data in the input bu
ff
er are
discarded, and an error is recorded in the ESR status register.
4.4
Ethernet
To connect to the LDC500 via the ethernet interface, the user must first
configure the network parameters. Once connected to local network
(or simple ethernet crossover cable), establish a socket connection to
TCP
/
IP port 8888. Send a blank line to initialize the connection, and
then send the
ULOC
1
command to unlock the ethernet command
LDC500 Series Laser Diode Controllers
