Serial Interface; Interface Configuration; Operating Considerations - Keithley 6517A User Manual

3.27 RS-232 Serial Interface
The Model 6517A has a built-in RS-232 serial interface.
Over this interface, you can send program messages to the
instrument and receive response messages from the instru-
ment. You can also place the instrument in the talk-only
mode which allows you to dump readings to an external lis-
tening device, such as a serial printer.
The serial port of the Model 6517A can be connected to the
serial port of a computer for send/receive operation, or to a
listener (such as a serial printer) for talk-only operation. The
connection requirements are covered in paragraph 3.2.2.
The SCPI programming language can be used over the RS-
232 Serial Interface to communicate with the Model 6517A.
The DDC programming language cannot be used over the
RS-232 interface.
3.27.1 RS-232 Interface Configuration
Model 6517A:
The RS-232 Serial Interface is selected and configured from
the COMMUNICATION option of the MAIN MENU. The
MAIN MENU is accessed from the front panel by pressing
the MENU key. The following information summarizes the
steps to select and configure the RS-232 interface. For details
on using the MAIN MENU, see paragraphs 2.19, 2.19.2 and
Table 2-12. Paragraph 2.3.5 provides general rules to navi-
gate through the menu structure.
6. Select the RS-232 interface as follows:
• Press MENU
• Select COMMUNICATIONS
• Select RS-232
Switching from the GPIB interface to the
RS-232 interface resets the instrument to
the power-on defaults. In this case, you
will have to repeat step 1 to display the
RS-232 SETUP menu.
7. Continue on to select the interface mode. Select SEND-
RECEIVE to send and receive commands, or select
TALK-ONLY to send readings directly to a listener (i.e.
serial printer).
• Select CONTROL
• Select SEND-RECEIVE or TALK-ONLY
8. Set the BAUD rate, number of data BITS, type of PAR-
ITY and the number of STOP bits as follows:
NOTE
• Select BAUD
• Select 19200, 9600, 4800, 2400, 1200, 600
or 300
• Select BITS
• Select 7 or 8
• Select PARITY
• Select NONE, ODD or EVEN
• Select STOP
• Select 1 or 2
9. Continue on to select the data elements that you want to
include for each conversion. Use a manual range key
to toggle between yes (y) and no (n):
• Select ELEMENTS
• Select RDG, RDG#, UNIT, CH#, HUM,
ETEMP, TIME, STATUS
Data elements can be selected over the RS-232 interface us-
ing the :FORMat:ELEMents command (see paragraph 3.15).
All other RS-232 interface configuration settings have to be
changed from the front panel MAIN MENU.
Computer:
From your communications software, configure the RS-232
interface for your computer as follows:
• RTS-CTS OFF
• XON - XON: ON
• Local cho: ON
• Use VT-100 Terminal Emulation
• Make sure the RS-232 parameters (baud rate, data bits,
parity, and stop bits) of your computer matches the RS-
232 parameters of the Model 6517A.
3.27.2 RS-232 Operating Considerations
Response Messages (Queries) — After a query command is
sent and parsed, the response message will immediately be
sent to the computer. Thus, the computer should be ready to
receive the response message at that time.
Data Format — The RS-232 interface only supports the
ASCII data format. Therefore, whenever the RS-232 inter-
face is selected, the data format will default to ASCII. At-
tempts to change the data format using the :FORMat:DATA
command will result in an error message and the ASCII data
format will be retained.
Flow Control — The Model 6517A does not support any
form of hardware flow control. Software flow control is in
IEEE-488 Reference
3-157