Keithley 2657A, Reference Manual, Page: 198 / 805

Section 3: Functions and features Model 2657A High Power System SourceMeter® Instrument Reference Manual
3-84 2657A-901-01 Rev. B/December 2012
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()
Interlock
The Model 2657A is provided with an interlock circuit that must be positively activated in order for
the high voltage output to be enabled. The interlock helps facilitate safe operation of the equipment
in a test system. Bypassing the interlock could expose the operator to hazardous voltages that could
result in personal injury or death.
Overview
The Model 2657A digital I/O port provides an interlock line for use with a test fixture switch. When
properly used, the output of the SourceMeter instrument will turn off when the lid of the test fixture is
opened. See
DUT Test Connections (on page 2-41) for important safety information when using a
test fixture. Follow standard safety and electrical practices by verifying the correct operation of all
components related to system safety, including the interlock.
WARNING