Data Format - Keithley 6517B Reference Manual

Section 11: Remote operations Model 6517B Electrometer Reference Manual

Data format

The RS-232 interface only supports the ASCII data format. Therefore, whenever the RS-232 interface
is selected, the data format defaults to ASCII. Attempts to change the data format using the
:FORMat:DATA command results in an error message and the ASCII data format is retained.
Flow control
The Model 6517B does not support any form of hardware flow control. Software flow control is in the
form of X_ON (Control+Q) and X_OFF (Control+S) characters. If the input queue of the Model
6517B becomes more that 3/4 full (2048 characters maximum), the instrument issue an X_OFF
command. The control program should respond to this and stop sending characters until the Model
6517B issues the X_ON, which it does once its input buffer has dropped below half-full. The Model
6517B also recognizes X_OFF and X_ON sent from the controller. An X_OFF causes the Model 6517B
to stop outputting characters until it sees an X_ON. Incoming commands are processed after the <LF>
character is received.
Device clear action
A Control C (^C) sent over the interface interrupts the Model 6517B microprocessor and forces a
device-clear action to take place. This clears any pending operation and discards any pending output.
Note that ^X is also recognized as a device-clear character.
Reception of a break condition also causes a device-clear action and displays the appropriate error
message.
The Model 6517B signifies the completion of the device-clear by echoing back the "DCL" followed by
the carriage return and line feed characters.
Unique SCPI commands
The following SCPI commands are unique to the RS-232 interface and cannot be used over the GPIB
interface:
Take the 6517B out of remote
:SYSTem:LOCal
:SYSTem:REMote Put the 6517B in remote
:SYSTem:LLOCkout <b> Enable or disable local lockout
See SCPI command reference (on page 14-1) for more information on using these commands.
11-22 6517B-901-01 Rev. C / August 2015