Interlock And Test Fixtures; Operate; Analog Outputs - Keithley 6517A User Manual

Front Panel Operation
used to enable or disable resistive current limit, and is sum-
marized in Table 2-15.
1. From the CONFigure V-SOURCE menu, select RESIS-
TIVE LIMIT to display the options (on or off).
2. To select resistive current limiting, place the cursor on
the ON option and press ENTER. Conversely, to de-se-
lect resistive current limiting, place the cursor on OFF
and press ENTER.
3. Use the EXIT key to back out of the menu structure.
2.9.4 Interlock and test fixtures
The voltage source should be used with a test fixture that in-
corporates a safety interlock switch, such as the Keithley
Model 8002A High Resistance Test Fixture or the Keithley
Model 8009 Resistivity Test Fixture. By using the interlock
feature, the Model 6517A cannot source voltage when the lid
of the test fixture is open or ajar.
Interlock is automatically enabled when the appropriate in-
terlock cable is connected to the Model 6517A. When used
with the Model 8002A or 8009, the V-Source will go into
standby whenever the lid of the test fixture is open or ajar.
When using the V-Source with the Model 8009 Resistivity
Test Fixture, use the Model 6517-ILC-3 Interlock Cable as
shown in Figure 2-36. This cable uses an extra line to detect
which resistivity measurement type is selected at the test fix-
ture (surface or volume).
When using the V-Source with the Model 8002A High Re-
sistance Test Fixture, use the Model 8002-ILC-3 Interlock
Cable as shown in Figure 2-32. This cable provides the 4-pin
to 3-pin conversion required for the Model 8002A. More in-
formation on the Model 8002A and 8009 test fixtures is pro-
vided in paragraph 2.4.6.
WARNING
Do not connect the interlock of the
Model 6517A to the interlock of another
instrument. The interlock is designed to
be connected to a single-pole interlock
switch of a test fixture. If connecting two
or more Model 6517As to a single test
fixture, an isolated interlock switch for
each instrument is required. Connecting
multiple instrument interlocks to the
same switch could cause the safety in-
terlock system to fail.
2-50

2.9.5 Operate

WARNING
With the instrument in operate (OPER-
ATE indicator on), the displayed volt-
age level (possibly hazardous) will be
applied to the output terminals of the
V-Source. The V-Source should be kept
in standby until ready to safely source
voltage to a load.
The OPER key toggles the output between standby and op-
erate. In standby, the voltage source is removed from the rear
panel output terminals. In operate (VOLTAGE SOURCE
OPERATE indicator on), the voltage source is applied to the
output terminals.
A flashing VOLTAGE SOURCE OPERATE indicator de-
notes that the voltage source is in current limit as explained
in paragraph 2.9.3.
CAUTION
A relay switch, in series with OUTPUT
HI, is opened when the voltage source is
placed in standby. The transition to an
open output creates a potential for noise
spikes. The open output allows dielec-
tric absorption to recharge capacitors to
unexpected voltage levels.

2.10 Analog outputs

The Model 6517A has two analog outputs on the rear panel.
The 2V ANALOG OUTPUT provides a scaled 0-2V output
with a value of 2V corresponding to full-range input. The
PREAMP OUT is especially useful in situations requiring
buffering. These two analog outputs are discussed in the fol-
lowing paragraphs.
WARNING
When floating input Low above 30V
RMS from earth ground, hazardous
voltage will be present at the analog out-
puts. Hazardous voltage may also be
present when the input voltage exceeds
30V RMS in the volts function, or when
input currents exceed 30pA in the amps
function.
CAUTION
Connecting PREAMP OUT, COM-
MON, or 2V ANALOG OUTPUT to
earth while floating the input may dam-
age the instrument.