Model 250S1G6
12
Rev D
2.6.1.1
Setting the IEEE-488 (GPIB) Address
The IEEE-488 device address can be set to any number between 1 and 30. This selection is made by
navigating to the GPIB address selection screen. 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 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.
2.6.2
RS-232 Communication
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.
NOTE: This baud rate setting is shared by both the RS-232 port and the Fiber-Optic serial port.
The RS-232 port is setup as a Data Circuit-terminating Equipment (DCE) port. When connecting to a
Personal Computer (PC) a straight one-to-one cable should be used. A null modem is NOT needed. The
settings and pin-out diagram for this port can be found below.
Table 2-1. RS-232 Port Settings
Word Length
8 bits
Stop Bits:
1
Baud Rate:
User selectable (default is 19200)
Parity:
None
HW Handshake:
None
Table 2-2. RS-232 (DCE) Port Pin-out Diagram DB-9 Female
Pin 1
DCD
Pin 2
TD
Pin 3
RD
Pin 4
DTR
Pin 5
GND
Pin 6
DSR
Pin 7
CTS
Pin 8
RTS
Pin 9
Unused
