Shielding And Guarding - Keithley 4200A-SCS Reference Manual

Section 2: Connections and configuration
The maximum allowed voltage between circuit COMMON and chassis ground is ±32 VDC.The
maximum allowed voltages between the preamplifier signals are:
COMMON to chassis ground: 32 V
GUARD to COMMON: 250 V
SENSE or FORCE to GUARD: 40 V

Shielding and guarding

Many test situations require that the device under test (DUT) be shielded or guarded (or both) to
avoid detrimental effects caused by electrostatic interference, parasitic capacitance, system leakage
currents, and so forth.
•
If the device is to be shielded (but not guarded), connect the DUT shield to COMMON (see the
next figure).
•
If the device is to be guarded, connect the DUT shield to GUARD (inner shield of triaxial cable;
see the next figure).
A safety shield must be used whenever hazardous voltages (>30 V
present in the test circuit. To prevent electrical shock that could cause injury or death,
never use the 4200A-SCS in a test circuit without a properly installed and configured safety
shield.
See Guarding
2-2
peak
peak
peak
(on page 3-23) for more information on the principles and advantages of guarding.
Figure 2: Device shielding
Model 4200A-SCS Parameter Analyzer Reference Manual
RMS
4200A-901-01 Rev. C / February 2017
, 42 V ) will be
peak