Keithley 486 User manual

Model 486
PICOAMMETER
Model 487
PlCOAMMETER/SOURCE
QUICK REFERENCE GUIDE

INTRODUCTION
This quick reference guide contains descriptions of vari-
ous features and information concerning the operation of
the Model 4861487.
~21990,Keithley Instruments, Inc.
All rights reserved.
Cleveland, Ohio, U.S.A.
Document Number: 486-903-01 Rev. A
1

Asyst tsa registered trademarkof Asyst Software technologies.
Hewtett-Packard Is a registered trademark of Hewlett-Packard
Company.
IBM and ATare registeredtrademarksand PC/XTisatrademark
of International Business Machines, I~C.
PC&488 isa registered trademark of Capital Equipment Cow
ration.
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TABLE OF CONTENTS
SAFETY WARNINGS ......................... 5
ERROR MESSAGES ......................... 7
CURRENT MEASUREMENTS .................. 8
VOLTAGE SOURCE (Model 487) .............. 14
V/l OHMS MEASUREMENTS (Model 487) ....... 19
MENU .................................... 21
FRONT PANEL TRIGGERING ................. 22
EXTERNAL TRIGGERING .................... 24
DATA STORE OPERATION .................. 26
ANALOG OUTPUT .......................... 27
TALK-ONLY ............................... 28
IEEE-488 PROGRAMMING .................. .29
Device-dependent Commands ................. 29
Display Intensity ........................ 29
Reading Source ........................ 29
Zero Check and Correct .................. 29
Display ............................. ..3 0
V/lOhms ........................... ..3 0
Data Format ........................... 39
Hit Control ............................ 31
Self-Test .............................. 31
EOI and Bus Hold-off ................... .31
Default Conditions or Calibration ........... 32
SRQ ............................... ..3 2
Data Store ............................ 32
Operate .............................. 33
Filters ................................ 33
Interval ............................... 33
Range................................3 3
Integration ............................ 34
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Trigger ...............................
Status.. ..............................
Voltage Source (487)
i:l
.................... 35
Delay ................................
Execute ............................ 35 a
..3 5
Terminator .......................... ..3 5
Relative .............................. 36
Data Formats .............................. 36 a
SRQ Mask and Serial Poll Byte ................ 40
StatusWords ............................ ..4 1 a
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SAFETY WARNINGS
The following precautions should be observed before us-
ing Model 488/487. Refer to main manual for detailed
safety information and complete operating instructions.
The Model 48W487 is intended for use by qualified per-
sonnel who recognize shock hazards and are familiar
with the safety precautions required to avoid possible in-
jury. Read over the instruction manual carefully before
using the instrument.
Before operating the instrument, make sure the line cord
is connected to a properly grounded power receptacle.
Exercise extreme caution when a shock hazard is pre-
sent. Lethal voltages may be present on the test fixture or
the Model 487 output jacks. The American National Stan-
dards Institute (ANSI) states that a shock hazard exists
when voltage levels greater than 30V RMSor 42.4V peak
are present. A good safety practice is to expect that
hazardous voltage is present in any unknown circuit
before measuring.
Inspect the connecting cables, test leads, and jumpers
for possible wear, cracks, or breaks before each use.
5

For maximum safety, do not touch the Model 487 con-
nections, test fixture, test cables or connections to any
other instruments while power isapplied to the circuit un-
der test. Turn off all power and discharge all capacitors
before connecting or disconnecting cables or jumpers.
Also, keep the test fixture lid closed while power is ap-
plied to the device under test. Safe operation requires the
use of the lid interlock.
Do not touch any object which could provide a current
path to the common side of the circuit under test or power
line (earth) ground.
Do not exceed the maximum signal levels of the instru-
ment, as shown on the rear panel and as defined in the
specifications and operation section of the instruction
manual.
Connect the chassis of the test fixture to safety earth
ground using #I 8 AWG or larger wire.
Instrumentation and accessories should not be con-
nected to humans.
Maintenance should only be performed by qualified serv-
ice personnel. Before performing any maintenance, dis-
connect the line cord and all test cables from the instru-
ment.
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ERROR MESSAGES
Table 1. Error Messages
Message Description
NO DEFLTS Checksum error in default condi-
tion during power-up.
UNCAL Checksum error in calibration
during power-up
ROM ERROR Failed ROM self-test.
RAM ERROR Failed RAM self-test.
TRG OVERUN Trigger overrun; instrument trig-
gered while still processing a pre-
vious trigger.
CAL VALUE Calibration value conflicts with
the currently selected range.
CAL ERROR Calibration value not within allow-
able limits.
CAL LOCK Sent calibration command with
calibration switch (CAL LOCK)
disabled.
CAL ZCHK Cannot calibrate picoammeter
with zero check enabled.
INTERLOCK Tried to put V-Source of Model
487 in operate while an enabled
safety interlock switch is open.

CURRENT MEASUREMENTS
Current Ranges
SHIFT
q v RANGE A
El 0
AUTO
RANGE
The available current ranges of the Model 4861487 are
listed in Table 2.
2nA
20nA
200nA
2c1A
20/.iA
2oopA
2mA 2.19999inA
‘Higher voltages requirecurrent to be limitedto 3mA.
2.19999nA
21.9999nA
219.999nA
2.19999pA
21.9999pA
219.999uA
35OVdc
35OVdc
35OVdc
35OVdc
5OVdc
50Vdc
50Vdc
Table 2. Current Ranges
.

Autorange is enabled by pressing SHIFTand thenAUTO
RANGE in that order.
CAUTION
To avoid possible damage to the instru-
ment, do not apply more than 5OVdcto
the input when autorange is enabled
(unless an external series resistor to
limit current to 3mA is used).
Zero Check and Correct
ZERO
SHIFT CHECK
q El
CORRECT
When zero check is enabled, the input amplifier is inter-
nally disconnected from the input connector of the instru-
ment. A 1OOkGresistor shunts the input connector, and
the instrument displays the offset of the selected range.
When zero correction is performed, the offset is meas-
ured and algebraically subtracted from every subsequent
reading (including zero checked readings).
Zero check is enabled by pressing ZERO CHECK.
Pressing ZERO CHECK a second time disables the fea-
ture.
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