Using Output Enable - Keithley 2651A Reference Manual

Section 3: Functions and features
Digital I/O programming example
The programming commands below illustrate how to set Bit B1 of the digital I/O port high, and then
read the entire port value.
digio.trigger[1].mode = digio.TRIG_BYPASS
-- Set Bit B1 high.
digio.writebit(1,1)
-- Read digital I/O port.
data = digio.readport()

Using output enable

Overview
The Model 2651A digital I/O port provides an output enable line for use with a test fixture switch.
When properly used, the output of the System SourceMeter
the test fixture is opened. See
when using a test fixture.
When an interlock is required for safety, a separate circuit should be provided that meets the
requirements of the application to reliably protect the operator from exposed voltages. The
digital I/O port of the Model 2651A is not suitable for control of safety circuits and should not
be used to control a safety interlock.
Operation
When enabled, the output of the Model 2651A can only be turned on when the output enable line is
pulled high through a switch to +5 V (as shown). If the lid of the test fixture opens, the switch opens,
and the output enable line goes low, turning the output of the System SourceMeter
The output will not automatically turn on when output enable is set high. The output cannot be turned
back on until +5 V is applied to the output enable line.
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Model 2651A High Power System SourceMeter® Instrument Reference Manual
DUT Test Connections
WARNING
Figure 69: Using the output enable line
®
instrument will turn OFF when the lid of
(on page 2-42) for important safety information
2651A-901-01 Rev. A / March 2011
®
instrument off.