Keithley 4200A-SCS

There are low-voltage and high-voltage test fi xtures for the
4200A-SCS. Low-voltage fi xtures, such as the Keithley
Instruments 8101-PIV, are intended for applications that are less
than ±40 V. For these applications, an interlock is not needed.
High-voltage test fi xtures, such as the Keithley Instruments
LR:8028, can be used with applications that are greater than
±40 V. The test fi xture has a safety interlock switch connected
to its lid. When the lid is closed, the interlock circuit is closed
(asserted), and SMU ±200 V ranges are enabled.
Conversely, the interlock circuit is open (de-asserted) when the
lid is open, and the SMU ±200 V ranges are disabled.
High-voltage test fi xtures require extra precaution to ensure there
are no shock hazards.
For correct operation with the 4200A-SCS, the test fi xture should
have a normally open switch that is used for the interlock. An
open interlock condition occurs when the switch is open.
The 4200A-SCS functions on all current ranges and up to
±40 V without asserting the interlock. When the interlock
is not asserted, the maximum voltage on the SMU and
preamplifi er terminals is not hazardous.