Keithley 2461 Reference Manual

Model 2461
Interactive SourceMeter® Instrument Reference Manual Section 8:
TSP command reference
2461-901-01 A/November 2015 8-51
Details
You can use this command to place each digital I/O line into one of the following modes:
• Digital open-drain, output, or input
• Trigger open-drain, output, or input
• Trigger synchronous master or acceptor
A digital line allows direct control of the digital I/O lines by writing a bit pattern to the lines. A trigger
line uses the digital I/O lines to detect triggers.
The following settings of lineMode set the line for direct control as a digital line:
• digio.MODE_DIGITAL_IN: The instrument automatically detects externally generated logic
levels. You can read an input line, but you cannot write to it.
• digio.MODE_DIGITAL_OUT: You can set the line as logic high (+5 V) or as logic low (0 V). The
default level is logic low (0 V). When the instrument is in output mode, the line is actively driven
high or low.
• digio.MODE_DIGITAL_OPEN_DRAIN: Configures the line to be an open-drain signal. The line
can serve as an input, an output or both. When a digital I/O line is used as an input in open-drain
mode, you must write a 1 to it.
The following settings of lineMode set the line as a trigger line:
• digio.MODE_TRIGGER_IN: The line automatically responds to and detects externally generated
triggers. It detects falling-edge, rising-edge, or either-edge triggers as input. This line state uses
the edge setting specified by the trigger.digin[N].edge attribute.
• digio.MODE_TRIGGER_OUT: The line is automatically set high or low depending on the output
logic setting. Use the negative logic setting when you want to generate a falling edge trigger and
use the positive logic setting when you want to generate a rising edge trigger.
• digio.MODE_TRIGGER_OPEN_DRAIN: Configures the line to be an open-drain signal. You can
use the line to detect input triggers or generate output triggers. This line state uses the edge
setting specified by the trigger.digin[N].edge attribute.
When the line is set as a synchronous acceptor, the line detects the falling-edge input triggers and
automatically latches and drives the trigger line low. Asserting an output trigger releases the latched
line.
When the line is set as a synchronous master, the line detects rising-edge triggers as input. For
output, the line asserts a TTL-low pulse.
Example
digio.line[1].mode = digio.MODE_TRIGGER_OUT
Set digital I/O line 1 to be an output trigger
line.
Also see
Digital I/O lines (on page 3-89)
Digital I/O port configuration (on page 3-87)
trigger.digin[N].edge (on page 8-242)

Keithley 2461 Specifications

General

Maximum Current	7 A
Power	100 W
Resolution	6.5 digits
Source Measure Unit (SMU)	Yes
DC Voltage	100 V
Maximum Voltage	100 V
Display	5-inch capacitive touchscreen
Connectivity	USB, GPIB
Software	TSP
DC Current	7 A
Current Source Range	0 to 7 A
Voltage Measurement Range	100 mV to 100 V
Current Measurement Range	10 nA to 7 A
Voltage Measurement Resolution	100 nV