3 – 6
Remote Operation
3.3
Introduction
Remote operation of the DC205 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
voltage source from a remote computer through USB or RS-232, or
through the optical fiber and the SX199 interface to GPIB, RS-232, or
ethernet interfaces.
Where applicable, the corresponding front-panel interface to each
command is also indicated. 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 value for parameters is listed in
boldface
in the command
descriptions.
3.3.1
Interface configuration
The USB interface is implemented as a serial port emulator, with fixed
baud rate of 115,200 . The RS-232 DB-9 and optical fiber interfaces
TBD
are both configured at power on as 9600 baud, 8-bit, no parity or flow
control. The USB and RS-232 interfaces can be commanded to di
ff
er-
ent baud rates under program control with the
BAUD
command, but
the optical fiber interface is fixed at 9600 baud.
3.3.2
Buffers
The DC205 stores incoming bytes from the remote interfaces in sep-
arate 128-byte input bu
ff
ers. Characters accumulate in the input
TBD
bu
ff
er until a command terminator (
CR
or
LF
) is received, at
which point the message is parsed and enqueued for execution.
Query responses from the DC205 are bu
ff
ered in interface-specific
256-byte output queues. Queries are returned to the interface from
which they were received (RS-232 or optical).
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.
DC205 Precision DC Voltage Source
