Keithley 6482, Справочное руководство

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12-14 Return to Section Topics 6482-901-01 Rev. A / August 2012
Section 12: Remote Operations Model 6482 Dual-Channel Picoammeter / Voltage Source Reference Manual
Baud rate
The baud rate is the rate at which the Model 6482 and the programming terminal communicate.
Choose one these available rates:
• 57600
• 38400
• 19200
• 9600
• 4800
• 2400
• 1200
• 600
• 300
The factory default baud rate is 9600.
When you choose a baud rate, make sure the programming terminal or printer that you are
connecting to the Model 6482 can support the baud rate you selected. Both the Model 6482 and
the other device must be configured for the same baud rate.
Data bits and parity
The RS-232 interface can be configured to send and receive data that is 7 or 8 bits long using
even, odd, or no parity. No parity is only valid when using 8 data bits.
Terminator
The Model 6482 can be configured to terminate each program message that it transmits to the
controller with any of the following combinations of <CR> and <LF>:
<CR>
Carriage return
<CR+LF>
Carriage return and line feed
<LF>
Line feed
<LF+CR>
Line feed and carriage return
Flow control (signal handshaking)
Signal handshaking between the controller and the instrument lets the two devices communicate
with each other about readiness to receive data. The Model 6482 supports software flow control
(signal handshaking); it does not support hardware handshaking (flow control).
Software flow control is in the form of XON and XOFF characters. This flow control is enabled
when XON-XOFF is selected from the RS-232 FLOW CONTROL menu. When the input queue of
the instrument becomes more than 3/4 full, the instrument issues an XOFF character. The control
program should respond to this and stop sending characters until the Model 6482 issues the XON
character (which it will do when its input buffer has decreased below half-full). The Model 6482
recognizes XON and XOFF characters sent from the controller. An XOFF character will cause the
instrument to stop outputting characters until it receives an XON character. Incoming commands
are processed after the <CR> character is received from the controller.
If NONE is the selected flow control, there will be no signal handshaking between the controller
and the Model 6482. Data will be lost if transmitted before the receiving device is ready.
RS-232 connections
The RS-232 serial port ( Figure 12-3 ) is connected to the serial port of a computer using a straight-
through RS-232 cable terminated with DB-9 connectors. Do not use a null modem cable. The