Keithley 487, 486 User Manual

Model 486

PICOAMMETER

Model 487

PlCOAMMETER/SOURCE

QUICK REFERENCE GUIDE

INTRODUCTION

This quick reference guide contains descriptions of vari­ous 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 ts a registered trademark of Asyst Software technologies.

Hewtett-Packard Is a registered trademark of Hewlett-Packard

Company.

IBM and AT are registered trademarks and PC/XT is a trademark
of International Business Machines, I~C.
PC&488 is a registered trademark of Capital Equipment Cow
ration.

2

TABLE OF CONTENTS

SAFETY WARNINGS

ERROR MESSAGES ......................... 7

CURRENT MEASUREMENTS

VOLTAGE SOURCE (Model 487) .............. 14

V/l OHMS MEASUREMENTS (Model 487)

MENU .................................... 21

FRONT PANEL TRIGGERING ................. 22

EXTERNAL TRIGGERING .................... 24

DATA STORE OPERATION .................. 26

ANALOG OUTPUT .......................... 27

TALK-ONLY

IEEE-488 PROGRAMMING .................. .29

Device-dependent Commands ................. 29

Display Intensity ........................ 29

Reading Source ........................ 29

Zero Check and Correct .................. 29

Display
V/lOhms
Data Format

Hit Control ............................ 31

Self-Test
EOI and Bus Hold-off

Default Conditions or Calibration ...........

SRQ

Data Store ............................ 32

Operate

Filters ................................ 33

Interval ............................... 33

Range................................3 3

Integration

...............................

.............................

...............................

.........................

..................

...........................

...........................

..............................

...................

..............................

............................

.......

19

28

..3 0
..3 0

39
31

.31

32

..3 2

33

34

5
8

3

Trigger ...............................

Status.. ..............................

Voltage Source (487)

Delay ................................

Execute ............................

Terminator ..........................

Relative ..............................

Data Formats
SRQ Mask and Serial Poll Byte
StatusWords

..............................

............................

....................

................

i: l

35

..3 5

35 a

..3 5

36
36
40

..4 1

a

a

4

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 per­sonnel who recognize shock hazards and are familiar
with the safety precautions required to avoid possible in­jury. 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 RMS or 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 con­nections, test fixture, test cables or connections to any
other instruments while power is applied to the circuit un­der 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 ap­plied 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 instru­ment, 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 serv­ice personnel. Before performing any maintenance, dis­connect the line cord and all test cables from the instru­ment.

6

ERROR MESSAGES

Table 1. Error Messages

Message

NO DEFLTS
UNCAL
ROM ERROR

RAM ERROR
TRG OVERUN

CAL VALUE
CAL ERROR

CAL LOCK

CAL ZCHK
INTERLOCK

Description

Checksum error in default condi­tion during power-up.
Checksum error in calibration
during power-up
Failed ROM self-test.
Failed RAM self-test.
Trigger overrun; instrument trig­gered while still processing a pre­vious trigger.
Calibration value conflicts with
the currently selected range.
Calibration value not within allow­able limits.
Sent calibration command with
calibration switch (CAL LOCK)
disabled.

Cannot calibrate picoammeter
with zero check enabled.
Tried to put V-Source of Model

487 in operate while an enabled

safety interlock switch is open.

CURRENT MEASUREMENTS

Current Ranges

SHIFT

q

The available current ranges of the Model 4861487 are
listed in Table 2.

Table 2. Current Ranges

v RANGE A

El 0

AUTO

RANGE

.

2nA

20nA

200nA

2c1A

20/.iA

2oopA

2mA

‘Higher voltages require current to be limited to 3mA.

2.19999nA

21.9999nA

219.999nA

2.19999pA

21.9999pA

219.999uA

2.19999inA

35OVdc
35OVdc
35OVdc
35OVdc

5OVdc
50Vdc
50Vdc

Autorange is enabled by pressing SHIFTand then AUTO

RANGE in that order.

To avoid possible damage to the instru­ment, do not apply more than 5OVdc to
the input when autorange is enabled
(unless an external series resistor to

limit current to 3mA is used).

CAUTION

Zero Check and Correct

ZERO

SHIFT

CHECK

q El

CORRECT

When zero check is enabled, the input amplifier is inter­nally disconnected from the input connector of the instru­ment. A 1 OOkG resistor shunts the input connector, and
the instrument displays the offset of the selected range.

When zero correction is performed, the offset is meas­ured 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 fea­ture.

9

When zero correction is performed, only the present

range is zero corrected. Before making measurements, it
is recommended that each current range be zero cor­rected.

To perform zero correction:

1. Enable zero check.

2. To perform zero correction, press SHIFT and then
CORRECT in that order.

Filters

SHIFT

cl

Filtering is used to stabilize noisy measurements. The
Model 486/487 has two available filters; a digital filter and
an analog filter. The digital filter bases the reading on the
weighted average of a number of measurement conver­sions. The analog filter is a simple RC filter whose time
constant varies with the selected range.

When the filter is enabled, the selected filter(s) (digital fil­ter, analog filter or both) will be used.

10

To check or change the filter selection:

Press SHIFT and then FILTER SELECT in that or­der. One of the following messages will be dis­played to indicate the currently selected filter(s):

FILTER DIGITAL
FILTER ANALOG
FILTER DIG+AN

To select a different filter, use the rotary knob or the

4 and b keys to display the desired filter selection.

Enter the displayed filter selection by pressing
SHIFT and then FILTER SELECT.

(Digital filter selected)
(Analog filter selected)
(Both digital and analog

filters selected)

Rel

REL

0

q

The rel (relative) feature serves as a means of baseline
suppression by allowing a stored offset value to be sub­tracted from subsequent readings. When rel is enabled,
the instrument takes the currently displayed reading as a
baseline value. All subsequent readings represent the
difference between the applied signal level and the
stored baseline.

11

A baseline can be established for both current and VII
ohm measurements and is “remembered” by both func­tions.

Rel is enabled by pressing the REL key. Pressing REL a

second time disables the feature.

Making Current Measurements

To make current measurements:

1. Select a current range that is appropriate for the ex­pected measurement or enable autorange (press
SHIFT and then AUTO RANGE).

2. Enable zero check and, if the display is not zeroed,
perform zero correction by pressing SHIFT and
then CORRECT.

3. Connect the current to be measured to the input of
the Model 486/487 (see Figures 1 and 2).

4. Disable zero check and read the measured current
on the display of the Model 486/487.

12

Input Connector

Max Overload

2nA - 2pA Range; 35OVdc

2OpA - 2mA Range;

50 Vdc

Chassis Gmund

Fiaure 1. Triax InDut Connector (3-Lua)

Model 486

Figure 2. Picoammeter Connections

VOLTAGE SOURCE

(Model 487)

The voltage source may float. However,

CAUTION

neither V-Source terminal may ever be
more than 500V above chassis.

V-SOURCE OUTPUT

500V MAX TO ,& OR.+

I HI

LO 1

5oov
MAX

Figure 3. Model 487 V-Source Output Terminals

Table 3. Model 487 V-Source

14

Test Fixture and Interlock

The voltage source of the Model 487 is designed to be

used with a test fixture that incorporates a safety interlock
switch, such as the Keithley Models 8002A High Resis­tance Test Fixture. By using the interlock feature, the

Model 487 cannot source voltage when the lid of the test

fixture is open or ajar.

Adjusting V-Source Level

The rotary knob and the4 and, keys are used to adjust

the V-Source level and select range.

With the instrument in operate (OPER-

WARNING

ATE indicator on), the displayed voltage
level (possibly hazardous) will be ap
plied to the output terminals of the V­Source. The V-Source should be kept in
standby until ready to safely source
voltage to a load.

15

Preset

PRESET

Preset allows the V-Source to be toggled between two

preset values.

To preset a V-Source level:

1.

Enable preset by pressing PRESET. Indicator wljl
turn on.

2.

Adjust the V-Source to the desired range and level.

3.

Disable preset by again pressing PRESET.

4.

Whenever preset is enabled, V-Source will adjust
to the value and range set in step 2.

I-Limit

The V-Source has current limit (l-limit) capabilities to pro­tect the instrument and external current sensitive circuitry
from possible damage. The V-Source can be set for an

l-limit of 25pA or 2.5mA.

When l-limit occurs, the OPERATE indicator will flash.

16

To set l-limit:

1.

Keep pressing and releasing MENU until the cur­rently selected i-limit is displayed:

ILIMIT

or

ILIMIT

2.

Use the rotary knob to display the desired l-limit

251rA

2.5mA

value.

3.

to enter the displayed l-limit, press MENU.

Operate

5oov 2mA

MAX

OPERATE

0

III

FLASHES
IN I LIMIT

The OPERATE key toggles the output between standby
and operate. In standby, the V-Source is removed from
the rear panel output terminals. In operate, V-Source is
applied to the output terminals.

17

V-Source Operation

While in standby, connect the V-Source as shown

1.
in Figure 4.

Use the rotary knob, and the 4 and b keys to set

2.
the desired voltage range and level.

Select the appropriate l-limit (25pA or 2.5mA).

3.

4. Press Operate.

To disable the V-Source, again press OPERATE.

5.

HI r

Model 487

3anana r;
‘lug Cables

-%---I

Figure 4. Basic V-Source Connections

18

--

Safety

7

1 Shield

V/I OHMS MEASUREMENTS
(Model 487)

By using the V-Source in conjunction with its picoamme-

ter, the Model 487 can make resistance measurements

as high as 5.05 x 10i6fI. With V/I ohms selected, the re­sistance is automatically calculated from the applied volt­age and measured current (R=V/I) and displayed (in
ohms) on the Model 487.

The V/I ohms function is enabled by pressing SHIFT and

then OHMS.

To make VA ohms measurements:

With zero check enabled and the V-Source in

1.
standby, connect the circuit shown in Figure 5.
Select a current range that gives the nearest full

2.
scale reading or autorange, and perform zero cor­rection by pressing SHIFT and then CORRECT.
Set the V-Source to OV on Ihe range that will be

3.
used and press OPERATE to enable the source
output.

4.

Press REL to cancel offset current.
Set the V-Source to the desired voltage level.

5.
Disable zero check. The current measurement will

6.
be displayed.
Enable V/I ohms by pressing SHIFT and then

7.
OHMS.
To measure from a baseline resistance, enable ref

8.
while in V/I ohms.

19

Figure 5. V/I Ohms Connections (Source V

20

Measure I)

MENU

The menu items are listed in Table 4. In general, each
press of the MENU key displays a menu item in the order
shown in the table. The available selections of the dis­played menu items are selected and displayed with the
rotary knob or the4 and, keys. The displayed option of
the displayed menu item is selected by again pressing
MENU. To exit the menu, press SHIFT and then EXIT.

Table 4. MENU items

Menu Item

DATA STORE
DATA RECL
ILIMIT

INTEGRATE
IEEE-488
DEFAULTS

SELFTEST
DEBUG
CALIBRATE
CAL V SRC

1 Description

Arm data store and set buffer size
Recall data stored in buffer
Set current limit; 25t~A or 2.5mA
(Model 487 only)
Set integration period; fast or line
cycle (50 or 60Hz)
Set IEEE-488 address O-30 or se­lect Talk-only
Save steps as power-up defaults,
return to previously saved defaults,
or return to factory defaults
Test display and memory elements
Troubleshooting mode
Calibrate current range
Calibrate V-Source (Model 487

only)

21

FRONT PANEL TRIGGERING

Trigger

In general,

sources) Is penormea ay:

1. Press SETUP to display the setup.

2. Use the rotary knob to display the desired option of

3. Press SHIFT and then SETUP to select the dis-

Trigger Mode

In the one-shot mode, a separate trigger is required to in­itiate each reading. For the multiple mode, however, only
a single trigger is required.

Setups

trigger setup (mode, internal, delay and

I .

the setup.
played setup.

. .

22

Trigger Interval

Determines the time period between individual readings

when the instrument is in the multiple trigger mode.

The trigger interval can be set from 1Omsec to

999.999sec.

Trigger Delay

Time from the trigger point until the unit takes a reading.

In the multiple trigger mode, the delay period affects only

the first conversion; however in the one-shot trigger

mode, the delay period affects every conversion.

The Model 4861487 can be programmed for adelay inter­val from Osec to 999.999sec in 1 msec increments.

Trigger Sources

Available trigger source selections:

TRIG SRC EXTERNAL
TRIG SRC OPERATE
TRIG SRC BUS X
TRIG SRC GET
TRIG SRC TALK

23

EXTERNAL TRIGGERING

EXTERNAL METER

TRIGGER COMPLETE

INPUT OUTPUT

Figure 6. Trigger Connectors

Triggers on

Figure 7. External Trigger Pulse Specifications

24

Figure 8. Meter Complete Specifications

25

DATA STORE OPERATION

Storing Data

1. Set the trigger mode, interval and delay.

2. Arm data store and set buffer size as follows:
A. Press MENU until the data store is selected,

and use the rotary knob to display the follow­ing:

DATA STORE YES

B. Press MENU to display buffer size.
C. Use the rotary knob or thedand, keys to dis-

play the desired buffer size value.

D. Press MENU.

3. Press TRIGGER to initiate storage.

Recalling Data

1. Press MENU until data recall is selected, and use

the rotary knob to display the following message:

DATA RECL YES

2. Press MENU. The reading stored in the first mem­ory location will be displayed.

3. For sequential access, use the rotary knob.

4. To access a reading at a particular memory loca­tion, adjust the display to the desired location value.

5. To exit data recall, press SHIFT and then EXIT.

26

ANALOG OUTPUT

The Model 4861487 has a non-inverting analog output.
For a 200,000 count input, the analog output will be 2V.

27

TALK-ONLY

In talk-only, the Model 486/487 will talk continuously on
the IEEE-488 bus and output readings to a listen-only de­vice whenever a measurement conversion occurs.

To place the Model 4861487 in talk-only:

1. Press and release MENU until the present
IEEE-488 selection is displayed.

2. Use the rotary knob to display talk-only as follows:

IEEE-488

3. Press MENU. The TALK indicator will turn on.

4. Exit the menu by pressing SHIFT and then EXIT.

28

TALK ONLY

IEEE-488 PROGRAMMING

Device-dependent Commands

Ml

Reading Source

Readings from A/D
Single reading From data store
All readings from data store
Maximum reading from data store
Minimum reading from data store

Zero Check and Correct

Disable zero check

Enable zero check
Enable zero check and perform zero cor-

rection

29

Display

Da
D

Display up to 18 character (a) message
Cancel display mode

V/I Ohms

Disable V/I ohms
Enable V/I ohms

1 Data Format

ASCII rdgs with prefix
ASCII rdgs without prefix
ASCII rdgs and buffer locations with prefix
ASCII rdgs and buffer locations without

prefix

G4

Binary rdgs: IEEE Std 754 single-preci­sion, bytes reversed for Intel CPUs

G5

Binary rdgs: IEEE Std 754 single-preci­sion, bvtes in normal order for Motorola
CPUS -

~ G8

Binary rdgs: counts and exponent, bytes
reversed for Intel CPUs

G7

Binary rdgs: counts and exponent, bytes
in normal order for Motorola CPUs

30

Hit Control

Hit DISPLAY INTENSITY key

L-L

Hit LOCAL key
Hit SHIFT key

E

K
H7
H8
HQ
H10
Hi1
H12
H13

Hit MENU key
Hit ZERO CHECK key
Hit FILTER key
Hit RANGEI key
Hit REL key
Hit RANGEAkey
Hit SETUP key
Hit TRIGGER key
Hit OPERATE key (487)

!$FtESET key (487)
Hi4 ’
HI5
H16
Hi7

Self-Test

Hit

R Hit otary Knob counterclockwise

Hit Rotary Knob clockwise

Perform ROM/RAM self-test
Perform disalav and ROM/RAM self-test

i EOI and Bus Hold-off

1; EnableEOIandbushold-offonX 1

Disable EOI enable bus hold-off on X
Enable EOI, disable bus hold-off on X
Disable both EOI and bus hold-off on X

31

I

Default Conditions or Calibration

LO

ki
L3,V

L4
L5
L6

SRQ

K
M2

Ii:
Ml6
M32
Ml28

Return to factory default conditions and
save (L-f)
Save present states as default conditions

Return to saved default conditions
Calibrate present measurement range
using “v”; v=-2mA to +2mA

Calibrate zero on present voltage source

range (Model 487 only)
Calibrate full scale on present voltage
source range (Model 487 only)

Prepare to calibrate present voltage

source range (Model 487 only)

Disable SRQ

Reading overflow

Data store full

Data store half full

Reading done

Ready

Error

Voltage Source Error (Model 487 only)

32

Arm data store; set buffer size ‘W’ where

Place voltage source in operate

g

Range

Disable digital and analog filters
Enable digital filter; disable analog filter
Disable digital filter; enable analog filter
Enable digital and analog flters

Enable autorange
Select 2nA range
Select 20nA range
Select 200nA range
Select 2juI range
Select 2OpA range
Select 200pA range
Select 2mA range
No range
No range
Disable autoranoe

I

33

I lntearation

Trigger

I

Fast integration; 1.6msec at 4-112 digit

or 2Omsec (5OHz) at 5-l/2 digit resolution

TO

T:
T3

z

G
T8

TQ

Status

34

Multiple on Talk

One-shot on Talk

Multiple on GET

One-shot on GET

Multiple on X
One-shot on X
Multiple on External Trigger

One-shot on External Trigger

Multiple on Operate (487)
One-shot on Operate (487)

Send machine status word
Send error status word
Send model number and firmware revi­sion
Send calibration value
Send interval

Send delay
Send relative value for current

Send relative value for V/I ohms
Send voltage source value (487)
Send voltage source error status word
(487)

I Voltaae Source 14871

I

Vn,r,l Specify voltage source level “n” in volts,

range “r” and limit “I”
n: -505 to ~505
r: 0 = 50V range; 1 = 500V range
I: 0 = 2OuA limit: 1 = 2mA limit

i Delav

Wn

Delay trigger “n”

Execute
X Execute other device-dependent com-

mands

Terminator

CR LF

?Y

LF CR

CR

E

Y4

LF
Nnnn

35

Relative

Disable relative

E
z2,V

23

Enable relative using present reading as
baseline
Enable relative using ‘V as baseline;
v = -2mA to +2mA for current = On to

50.5PR for V/I ohms
Enable relative using the baseline previ­ously defined

Data Formats

Finure 9. ASCII Data Format (G2: Prefix and Suffix)

36

G5 Format (Normal order ; MotMok CPU)

Header *

A-

68yies 1 Bylei Byte2 Byle3 Byte4 a--

sign Exponent

(1 Bii (SB%s) (23 Bits)

G4 Format (Reverse mier : lnlel CPU) : Fleading bytes sem in reverse order:

‘Headers Rr IJm G4 and G5 fcxmak are shown in FQ. 4.4

** When remllinp data from the huller. one header

k l&wed by one or more readings. dependinp
on btmer sire.

Reading *’

II

l

(single preciston, IEEE-75-4)

i-leader. Byte 4. Byte 3, Byte 2. Byte 1

I

Manlksa

I

Figure 10. G4 and G5 Binary Data Formats

(IEEE Std. 754)

37

II

I

SEytesILSBI 1 IMSB)LSB] 1

Co:nhErpdnent

(16 bitsignecij (16 bittiQnw$

I

I

MSB ---

r

6wslMSBI ( ILSBIMSBI 1 1

VExpdnarn

’ Headers for the G6. and G7 formats are shown in Fig. 4-4

‘*When recalling data from the buffer, one header

is followed by one or more readings, dependiw

on buffer&e.

NME : True k?adinQ = Counts X 10 -

Figure 11. G6 and G7 Binary Data Formats

(Counts/Exponent)

38

LSB -**

G5 and 07 Header (6 bytes) :

Figure 12. Headers for Binary Formats

39

1 = Data Stare Full

1 = Data Store Half Full

t- we @w

l=RQS:SRQbyMiB/487

1 = VobJe SourGw Emr

1 = FwcmQ Done

*AhwysOforkbdel4SS

n f 2

2.

EL

x

5

J

g

t

a

3

Status Words

UO Machine Status Word

Model 466:

466 AD BO Cl GO H** JO KO MOO0 NO00
P3 Rll Sl T6 YO 20 c*

Model 467: 467 A0 BO Cl FO GO H* JO KO MOO0

NO00 00 P3 RI1 Si T6 VO1 YO ZOO c*

‘Calibratkm switch (CAL LOCK) position;

“Last pressed key

DISPLAY INTENSITY (A)

D=Normal
1 -Dim
z=off

READING SOURCE (B)

O=AfD Reading
1 -One data store reading
2=All data store reading
3=Max data store reading
4=Min data store reading

ZERO CHECK and
CORRECT (C)

O-Zero check disabled
I-Zero check enabled

VII OHMS (F)

0-W Ohms disabled
1-W Ohms enabled

DATA FORMAT(G)

O=Rdg with prefix (ASCII)
1 =Rdg without prefix (ASCII)
2=Rdg and buffer location

with prefix (ASCII)

3=Fidg and buffer location

wifhout prefix (ASCII)

4=Binary rdg - IEEE Std 754

single - $ecfslon, bytes
reversed for Intel CPUs

B-Binary Rdg - IEEE Sfd 754

singie - f?reclsion, bytes in
normal order for Motorola
CPUS

B=Binary Rdg -counts and

exponent, bytes re­versed for Intel CPUs

7=Binary Rdg -Counts and

exponent, bytes in normal
order for Motorola CPUs

Figure 14. UO Machine Status Word (Factory

Defaults Shown)

41

UO Machine Status Word (cont.)

ilT CONTROL (H)
XkPOWER’

li=DISPtAY INTENSITY’
12=LOCAL*
)3=SHIf=T
14=MENU*
XI-ZERO CHECK*
16=FILTER’
;$=;;rGEv *

&fANGE&
lo-SETUP*
1 I-TRIGGER’
12=OPERATE’
13=PRESET’
14-d’
15-b’
16=Knob rotated CCW
17=Knob rotated CW
*Last pressed

SELF-TEST (J)

O=No errors
1 -ROM error
2&AM error
3=ROM and RAM error

EOI & BUS HOLD-OFF(K)

O=EOI and Hold-off
I-No EOI and Hold-off
2=EOI and no Hold-off
3=No EOI and no Hold-off

SRQ (M)

OOO-Disabled
OOI-Reading overflow
002=Data Store Full

SRQ (M) (cant)

004=Data Store l/2 Full
008=Reading Done
01 G=Ready
032=Error

128=Voltage Source Error

DATA STORE SIZE (N)

OOO-Wrap around
nnn=OOi to 512

OPERATE (0)

O-V-Source in Standby
1 -V-Source in Operate

FILTERS (P)

O=Both Filters Disabled
1 =Digital Filter Enabled,

Analog Filter Disabled

Z=Digital Filter Disabled

Analog Filter Enabled

3=Both Filters Enabled

RANGE (RMN)

m: 0 = Autorange Disabled

1 PAutorange Enabled

n: l -2nA range

2- 20nA range
3=200nA range
4=2pA range

5=2OpA range
6=2OOuA range

7=2mA

INTEGRATION PERIOD(S)

O-Fast (4-1/2d)

1 =Line cycle (5-1i2d)

UO Machine Status Word (cont.)

TRIGGER (-I-)

O=Multiple on Talk

1 POne-shot on Talk
2=Multiple on GET
3=One-shot on GET
4=Multiple on X

5=Oneshot on X

6=Multiple on External

Trigger

7=Cne-shot on External

Trigger
8=Multiple on Operate
S=One-shot on Operate

VOLTAGE SOURCE
(vmn)

m: 0 = 50V range

1=5OOV range

n: O-25pA Limit

1=2.5mA Limit

;Ei$llFATOR (Y)

P

1..LFCR

2&R

3=LF

4-None

RELATIVE (Zm or Zmn)

m: O-Current Rel Disabled

l-current Rel Enabled

n: 0-W Ohms Rel Disabled

1 -V/I Ohms Rel Enabled

CAL LOCK (c)

O&witch in disabled

([tied) position

a&witch in enable (locked)

position

43

11

Cal Constants

I= E* PROM Defaults

I! P 0

G

1 I IDDCO 1 = v-source confm

l=IDDC I= v-sourcs

m

5

2

on on 011 on 011

on on on

r

r

4w487 on on on on on

s

1 ~ZeroCh6!&

1 =cs.lL!a?ked

‘I= Tf&w Overrun

1 = No Remote

$

3

2

ii

U2 through U8 Status Words

U2 Model Number and Firmware Revision

e.g.486A03

U3 Calibration Value

e.g. CV=+O.OOOOOE-O5A

U4 Trigger Interval

8.g. TI=001.236E+OOS

U5 Trigger Delay

e.g.TD=002.000E+OOS

U6 Relative Value (Current)

e.g. RV=+1.00000E-O3A

U7 Relative Value (V/I Ohms)

8.g.RV=+l.00000E+020HM

U8 Voltage Source Value

e.g. VS=+20.000E+OOV

Figure 16. U2 through U8 Status Words

45

U9 Voltage Source Error Status

467 O/I O/l

L

1 = Interlock Open

L

1 = Current Limited

Figure 17. U9 Voltage Source Error Status Word

46

Keithley Instruments, Inc.

28775 Aurora Road
Cleveland, Ohio 44139

Printed in the U.S.A.