Stanford Research Systems DS345, Manual

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The DS345 Function Generator may be remotely programmed via the RS232
or GPIB (IEEE-488) interfaces. Any computer supporting one of these inter-
faces may be used to program the DS345. Only one interface is active at a
time. The active interface may be set by entering either the GPIB or RS232
menu and turning the interface ON. The interfaces are exclusive, so while
one is on the other will always be off (not responsive). All front and rear panel
features (except power) may be controlled.
GPIB Communications
The DS345 supports the IEEE-488.1 (1978) interface standard. It also sup-
ports the required common commands of the IEEE-488.2 (1987) standard.
Before attempting to communicate with the DS345 over the GPIB interface,
the DS345's device address must be set. The address is set in the second
line of the GPIB menu (type [SHIFT][GPIB] twice) and can be set between 0
and 30.
RS232 Communications
The DS345 is configured as a DCE ( transmit on pin 3, receive on pin 2) and
supports CTS/DTR hardware handshaking. The CTS signal (pin 5) is an out-
put indicating that the DS345 is ready, while the DTR signal (pin 20) is an in-
put that is used to control the DS345's transmitting. If desired, the handshake
pins may be ignored and a simple 3 wire interface (pins 2,3 and 7) may be
used. The RS232 interface baud rate may be set in the second line of the
RS232 menu (type [SHIFT][RS232] twice). The interface is fixed at 8 data
bits, no parity, and 2 stop bits.
Front Panel LEDs
To assist in programming, the DS345 has 3 front panel status LEDs. The
ACT LED flashes whenever a character is received or sent over either inter-
face. The ERR LED flashes when an error has been detected, such as an il-
legal command, or an out of range parameter. The REM LED is lit whenever
the DS345 is in a remote state (front panel locked out).
Data Window
To help find program errors, the DS345 has an input data window which dis-
plays the data received over either the GPIB or RS232 interfaces. This win-
dow is the DATA menu and displays the received data in hexadecimal for-
mat. Scroll back and forth through the last 256 characters received using the
MODIFY up/down arrow keys. A decimal point indicates the most recently re-
ceived character.
Command Syntax
Communication with the DS345 uses ASCII characters. Commands may be
in either UPPER or lower case and may contain any number of embedded
space characters. A command to the DS345 consists of a four character
command mnemonic, arguments if necessary, and a command terminator.
The terminator may be either a carriage return <cr> or linefeed <lf> on
RS232, or a linefeed <lf> or EOI on GPIB. No command processing occurs
until a command terminator is received. All commands function identically on
GPIB and RS232. Command mnemonics beginning with an asterisk "*" are
IEEE-488.2 (1987) defined common commands. These commands also func-
tion identically on RS232. Commands may require one or more parameters.
Multiple parameters are separated by commas ",".
Multiple commands may be sent on one command line by separating them
by semicolons ";". The difference between sending several commands on
the same line and sending several independent commands is that when a
command line is parsed and executed the entire line is executed before any
other device action proceeds.
PROGRAMMING THE DS345
3-1