Keithley SourceMeter 2600 Series Reference Manual page 131

Series 2600 System SourceMeters Reference Manual
Test fixture
A test fixture can be used for an external test circuit. The test fixture can be a
metal or nonmetallic enclosure, and is typically equipped with a lid. The test circuit
is mounted inside the test fixture. When hazardous voltages (>30Vrms, 42Vpeak)
will be present, the test fixture must have the following safety requirements:
WARNING
Construction material – A metal test fixture must be connected to a known
safety Earth Ground as described in the above WARNING. A nonmetallic test
fixture must be constructed of materials that are suitable for flammability, voltage
and temperature conditions that may exist in the test circuit. The construction
requirements for a nonmetallic enclosure are also described in the WARNING.
Test circuit isolation – With the lid closed, the test fixture must completely
surround the test circuit. A metal test fixture must be electrically isolated from the
test circuit. Input/output connectors mounted on a metal test fixture must also be
isolated from the test fixture. Internally, teflon standoffs are typically used to
insulate the internal pc-board or guard plate for the test circuit from a metal test
fixture.
Interlock switch – The test fixture must have a normally-open interlock switch.
The interlock switch must be installed so that when the lid of the test fixture is
opened, the switch will open, and when the lid is closed, the switch will close.
WARNING
To provide protection from shock hazards, an enclosure should be
provided which surrounds all live parts.
Nonmetallic enclosures must be constructed of materials suitably
rated for flammability and the voltage and temperature
requirements of the test circuit.
For metallic enclosures, the test fixture chassis must be properly
connected to safety earth ground. A grounding wire (#18 AWG or
larger) must be attached securely to the test fixture at a screw
terminal designed for safety grounding. The other end of the
ground wire must be attached to a known safety Earth Ground.
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 Model 2601/2602 SourceMeter
is not suitable for control of safety circuits and should not be
used to control a safety interlock. The Digital I/O port of the
Model 2611/2612 can be used to control a safety interlock. The
Model 2611/2612 200V source range cannot be used unless the
interlock is enabled (see
Return to Section 3 topics
DUT Test Connections 3-15
Section 10).
2600S-901-01 Rev. A / May 2006