AR 20S6G18-L, Operating And Service Manual, Page: 23 / 50

Model 40S6G18-L
Rev E 7
2.4 REMOTE COMMUNICATIONS
This section describes remote operation of this product using the installed communications ports connected to
a remote device such as a personal computer. All ports are active at all times, however only one port may be
used at a time. Communicating through two or more ports at one time will cause data collisions and lost
commands or queries.
The REMOTE / LOCAL switch on the front panel allows for the amplifier to be controlled using the remote
communications ports or the front panel controls depending on its position. All remote queries will work in
either switch position. All remote commands will only work when the switch is set to
REMOTE
. When the
switch is set to REMOTE all front panel controls are disabled.
NOTE: Some of the following ports may not be installed on your amplifier.
2.4.1 IEEE-488 (GPIB) Communications
For GPIB operation, the device address is set using the front panel touch screen. Ensure that each device
connected to the GPIB is set to a unique address.
To send commands be sure that the amplifier’s address is set properly and that the controller has correctly
identified it as a “listening” device.
When sending commands via the GPIB interface, terminate with an EOI and a Line Feed character. The
amplifier will ignore characters following the termination.
2.4.1.1 Setting the IEEE-488 (GPIB) Address
The GPIB device address can be set to any number between 1 and 30. This selection is made by navigating to
the GPIB address selection screen (Section 3.3.1.5.4). To get there from the Main Menu, touch the User
menu button followed by the I/O menu button and finally the GPIB menu button. Touching any of the
buttons labeled 1 to 30 immediately sets the GPIB address to the corresponding value. A thin black outline
indicates the present GPIB address selection. When the back button is pushed the address selection is stored
to non-volatile memory. Therefore, if power is lost prior to hitting the back button any address selection
changes will be lost. The default GPIB address is 1.
2.4.2 RS-232 Communications
The RS-232 port is a serial communications bus. All commands and queries through this port must be
terminated with a Line Feed character. When a valid query is received, it is processed and the result is
immediately transmitted back over the RS-232 interface. This port is designed to time-out if there is no
activity on the bus for more than 5 seconds. At this time the internal buffer is cleared and a
TIMEOUT_ERROR message followed by a Line Feed character is sent out from this port.
The baud rate for the RS-232 port is user selectable from the RS-232/Fiber-Optic Serial Baud Rate selection
screen. To get there from the Main Menu, touch the User menu button followed by the I/O menu button and
finally the Serial menu button. A thin black outline indicates the present baud rate selection. When the back
button is pushed the baud rate selection is stored to non-volatile memory. Therefore, if power is lost prior to
hitting the back button any baud rate selection changes will be lost. The default baud rate is 19200.
NOTE: This baud rate setting is shared by both the RS-232 port and the Fiber-Optic serial port.