Remote Communication; Changing Operation From Local To Remote; Gpib Versus Rs-232 Communication; Command Syntax - ILX Lightwave LDT-5900 Series User Manual

Remote Communication

This section contains information about changing operation from local to remote,
GPIB vs RS-232 communication, the command set, command syntax, and error
and status registers. Before remote communications are initiated, be sure to
configure the GPIB or RS-232 as described above. Refer to Chapter 4,
Command Reference, for information about specific commands.

Changing Operation from Local to Remote

Sending a command over the GPIB or RS-232 interface will automatically put the
instrument in REMOTE mode. The REMOTE indicator in the SYSTEM section of
the front panel will illuminate when the controller is in remote operation mode.
When in REMOTE mode, all buttons and the knob are disabled, except for the
MAIN/LOCAL button. When the instrument is in REMOTE mode, pressing the
MAIN/LOCAL button on the front panel returns the instrument to LOCAL control
mode and re-enables front panel input.

GPIB Versus RS-232 Communication

The LDT-5900 Series Temperature Controller should not be run remotely via GPIB
and RS-232 at the same time. When using the RS-232 interface, the remote
GPIB command set is fully operable. Command syntax does not vary between
GPIB and RS-232 usage. However, the commands which affect GPIB hardware
operation will not be useful. For example, the user could send the "*SRE"
command via RS-232. However, any service request (SRQ) via GPIB would not
be visible since RS-232 has no hardware to support it. This is because SRQ is a
function of the GPIB interface hardware and is not available via RS-232.
All commands received by the RS-232 interface are acknowledged by the LDT-
5900 transmitting "Ready" when the command operation is complete. Queries
are acknowledged by the specific query response message. Multiple
commands/queries separated by semicolons and issued as one command string
are only acknowledged with a "Ready" response if the entire command string
contains no queries. (See the Command Separators section later in this chapter
for additional details.) The LDT-5900 terminates all RS-232 transmitted
responses with <CR><LF> (Carriage Return - Line Feed) characters. The LDT-
5900 expects all commands/queries sent via the RS-232 interface to be
terminated with any of the following characters: <CR> (Carriage Return), <LF>
(Line Feed), or ASCII 250 character (Hex 0xFA).

Command Syntax

This section describes command syntax and structure. You need this information
to effectively write GPIB or RS-232 control programs. The syntax of GPIB
commands follow the rules defined in the ANSI/IEEE 488.2-1987 standard.
01_10
R E M O T E O P E R A T I O N S
Remot e Comm unica t ion
3
C H A P T E R
43
LDT-5980/ 5948