Keithley 2000 User Manual

Selecting signal handshaking (flow control)
Signal handshaking between the controller and the instrument allows the two devices to com-
municate to each other regarding being ready or not ready to receive data. The Model 2000 does
not support hardware handshaking (flow control).
Software flow control is in the form of X__ON and X__OFF characters and is enabled when
XonXoFF is selected from the RS232 FLOW menu. When the input queue of the Model 2000
becomes more than 3/4 full, the instrument issues an X_OFF command. The control program
should respond to this and stop sending characters until the Model 2000 issues the X_ON, which
it will do once its input buffer has dropped below half-full. The Model 2000 recognizes X_ON
and X_OFF sent from the controller. An X_OFF will cause the Model 2000 to stop outputting
characters until it sees an X_ON. Incoming commands are processed after the <CR> character
is received from the controller.
If NONE is the selected flow control, then there will be no signal handshaking between the
controller and the Model 2000. Data will be lost if transmitted before the receiving device is
ready.
Perform the following steps to set flow control:
1. Access the RS-232 configuration by pressing SHIFT and then RS232. You see: RS 232:
ON (assuming you have already selected the RS-232 interface).
2. Go to the flow control field by using the
▲ or ▼ key. You see FLOW: <control>.
3. Access the flow control options by pressing the key. You see the flow control selec-
tion blinking.
4. Use the
▲ or ▼ key to display the desired flow control (NONE or XonXoFF) and press
ENTER. You will then be prompted to set the terminator. Continue on for information
about the terminator. You can return to the measurement mode by pressing EXIT.
Setting terminator
The Model 2000 can be configured to terminate each program message that it transmits to the
controller with any combination of <CR> and <LF>. Perform the following steps to set the ter-
minator:
1. Access the RS-232 configuration by pressing SHIFT and then RS232.
You see: RS 232: ON (assuming you have already selected the RS-232 interface).
2. Go to the terminator field by using the
▲ or ▼ key.
You see TX TERM: <terminator>.
3. Access the terminator options by pressing the key.
You see the terminator selection blinking.
4. Use the
▲ or ▼ key to display the desired terminator (LF, CR or LFCR) and press
ENTER. The instrument will return to the measurement mode.
Remote Operation 4-7

Keithley 2000 Specifications

General

Brand	Keithley
Model	2000
Category	Multimeter
Language	English