Keithley 2657A, Quick Start Manual

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Wiring the interlock
The Model 2657A is a high voltage instrument that can output
hazardous live voltages. It is designed to be used with a test fixture or
in a system in which operators are not exposed to such hazardous
voltages.
The Model 2657A provides an interlock as a method for ensuring
operator safety. The output of the Model 2657A can only be turned
on when the interlock line is enabled. If you attempt to turn on the
output when the interlock is disabled, the instrument will generate
error code 802, “Output blocked by interlock.”
The interlock line is enabled when it is pulled high through a switch
to > +4 V. To drive the interlock pin high, the external supply must
supply a minimum of 50 mA. The interlock line is disabled when the
signal applied is < +4 V. The absolute maximum input is

0.4 V to +6.0 V.
The interlock is intended for use through a normally open switch.
This switch may be installed on the lid of a test fixture, the enclosure
of a semiconductor prober or device handler, or on the doors of a
test equipment rack.
The interlock line is pin 24 of the digital input/output connector on
the rear panel of the Model 2657A.
A +5.0V pin is also available on the digital I/O connector (pin 22).
To use the interlock, connect the 5 V pin and the interlock pin to the
input and output respectively of the switch in your test system.
The following graphic shows how the interlock is intended to be used
with a generic test fixture.
If you are using the Model 2657A with the Model 8010 High Power
Device Test Fixture, the interlock connection may be made using the
CA-558-2 cable assembly. Refer to the Model 8010 User's Manual for
information on how to connect the Model 2657A to the Model 8010.