Keithley 616 Service manual

INSTRUCTION MANUAL Digital Electrometer

Model 616

NINTH PRINTING, FEBRUARY, 1980, CLEVELAND, OHIO, U. S. A.

DOCUMENT NO. 28039

COWENTS

CONTENTS

Section

SpECIFIC*TIONS ---------------------------------------------------- i”

1. GENW&jJ, I~O~TpJ)q _---__------__-_-___----------------------- 1

INITIAL pREp)&qlON _____-_-_-_-_-_---------------------------- 4

2.

()PEI(ATING lNS*RlJCTIONS __-_------------------------------------ 5

3.

4. THEORY ,-Jr OpE~T~ON __-___------__-_-___----------------------- 21

5. *CCESSORIES __-___--_--__-__________________________----------- *g

6. MAINTENANCE -------------------_------------------------------ 33

7. REPLACEABLE PARTS ---_-_--------___-__-------------------------

SCHEMATICS ___-____________________________________----------------

Page

37 61

MODEL 616

1LL”STRATIONS

ILLUSTRATIONS

Figure NO.

1 2 3 4 5 6

Front Panel Front Panel Controls Rear Panel Connectors Triaxial Input Typical Display an 1OmV Sensitivity operation as B Voltmeter in NORMAL Mode

Title Page NO.

7 Operation a8 an Arcmeter in NORMAL Mode 8

Loading Effects in Ammeter Function

9 Operation as an Ohmmeter in NORMAL Mode 10 Operation as a Coulombmeter in FAST Mode 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

Null Method for Current Measurement

Volt-Ammeter

Resistance Method Unity Gain (Xl) Measuremene "se of

1V

Recorder Output Front Panel Of Model 6162 Dual Rack Mounting "sing Model 1007 Hardware Rear Panel of Model 616 and 6162 Diagram of b,rerconnecrion Cable between 616

Identification of Pins on Digital Output Connector Suggested Hook-up for Daea Lines Block Diagram of 61616162 System Timing Diagram for 6162 Outputs Overall Block Diagram of Model 616

Simplified Diagram of Amplifier Section Voltmeter Configuration - NORMAL Mode Ammeter Configuration - FAST Mode Coulombmeter Configuration - FAST Mode Ohmneter Configuration - NORMAL Mode Functional Black Diagram of *-m-o colwereer 25 Functional Black Diagram of Large Scale Integrated Circuit DigiLal Display Chassis Assembly - Exploded View BOtfOm cover Assembly Component Layout, PC-321 Gxnpanene Layout, PC-335 Component Layout, PC-322 Component Layout, PC-323 Component Layout, PC-324 Component Layout, PC-325

1 2 3 5 5 7 8

8 10 11 12 12 12 12 13 13 14

and 6162 14

16 18 19 19 21 22 23 23 24 24

26 26 39

39 53

54 55 57 59 60

1175

SPECIFICATIONS

MODEL 616

SPECIFICATIONS

iS AN AUTORANGING VOLTMETER RANGE: $10 microvolts per digit (1OmV full range) eo

Cl00 volts full range in five decade ranges. 100% overranging to 1999 0" all ranges.

KCUPACY (ZO'=C to 30°C): +(0.2% of reading x).1% of

range).

READING TIME: Less the" 4 seconds to within 0.1% of

final reading, except where limited by source char-

acteristics.

ZERO DRIFT: Less than (50 microvol~s M.Ol% Of range)

per 'C. and less than 100 microvolts per 24-hour period after two hours warm-up (during which drift

does "a~ exceed 500 microvolts). IOISE: Cl0 microvolts with input shorted. tNl'UT IMPEDANCE: Greater than 2 x 1014 ohms shunted

by 20 picofarads. Input resistance ms also be

selected in decade see"s from 10 ?o

POR”AL MODE REJECTION RATIO:

FQT voltage of line frequency and se least 10% of full raoge dc reading.

volts peak ac + dc. :OMMON "ODE RWECTION RATIO: Greater than 140 dB af

line frequency with 300 volts peak-to-peek from circuit Lo to chassis ground, up to 1011 ohm source me-

sistance, and se least 10% of full range dc reading. is AN AMMETER ?.ANGE:

range) to to.1 ampere full range in 13 decade

ranges. 100% overranging to 1999 on all ranges. u2cuRAGY (2OY to 30-C):

Range Switch setting AWurecy

YOISE: 2 x lo-15 ampere peak-to-peak on the most sen-

sitive range, exclusive of alpha particle disturbance. ,FFSET C"Rp,XNT: :OMMON MODE REJECTION: 300 volts peak-to-peak ae line

frequency from circuit La eo chassis ground on any range and with at least 10% of full range dc reading will not degrade accuracy more than 0.3% of range.

(Equivalent to 140 dB CMRR).

LS AN OHMMETER WGE: 1 ohm per digit (1000 ohms full range) co 1014

ohms full range in 12 decade ranges. 100% overranging to 1999 on all ranges.

uxxRAm (2OOC to 3ooc):

Range s;*tci seetinp

IETNOD: Two-terminal COnSt*nr--Curre"t. current equals

reciprocal of OHMS range.

RANGE

1OmV

10omv

1V

10 v

100 v

t10-16 ampere per digit (lo-13 ampere full

10-l Co 10-/A

lo-88

10-9 eo lo-1lA

Less than 5 x lo-15 ampere.

103 to lo’&?

lOan

109 to 10120

NMRR 94dB 80dB SOdB 60dB 60dB

Maximum total input 200

k(O.54 of reading +O.l% of range) t(24 of reading +0.1X of range) CO% Of reading +a.l% Of range)

f(0.54 of reading tO.l% of range) C(2% of reading +O.l% of range)

+(5% of reading ffl.19. of range)

I1

10

MAX. AC

2v 2v

2ov p-p 2ov 0-p

2oov p-p

Accuracy

ohms.

e-p p-e

AS A COULOMBMETER RANGE: ?10-15 coulomb ,,er dinit (LO-12 coulomb full

range) to ?10-5 coulo;b fuli range in a decade ranges. 100% overranging to 1999 on all ranges.

ACCURACY (20°C to 3O'C): ~(5% of reading +O.l% of

range) 0" a11 ranges. AS A CONSTANT CURRENT SOURCE RANGE: 8 CurrentS in decade seeps from 10-5 fo lo-12

ampere using OHMS ranges. Hi eermina1 is positive. COmJLIANCE: up to 200 volts. ACCURACY (ZO'C eo 3O'C): 20.5% from 10-5 eo lo-7

ampere. *2% at 10-a ampere. ?5% from 10-9 to

10-12 ampere. LOAD REGULATION:

1011 ohms. GENERAL DISPLAY: 3 digits plus 1 overrange digit; decimal

position, polarity, and overload indicaeio"; 5 readings per second. Depending on sensitiviey setting, 3 least-si~ificant digits blink or blaok

"he" overload condition exists. POLARITY SELECTION: Automatic SENSITIVITY SELECTION: Automatic: Voltage sensi-

tivity selection is fully sutomstic.

selection is a"Wma?Lc hlo decades above and be-

low range switch setting for resistance, charge, and most current measurements. Manual: Front panel switch. Remote: Progrsnmsble with the Model 6162 Output/Control (optional).

ISOLATION:

than LO9 ohms shunted by 500 picofarads (decreasing to lOa ohms at 3O'C and 70% relative humidity). Circuit Lo ma" be floated UD to tlOO0 voles with respect eo chassis ground.

ANALOG OUTPUTS: Unity Gain: For dc inputs, oueput

is equal to input within 20 ppm far oueput cur;e"rs Of 1mA or less. In Jhe fasf mode output polarity is opposite input polarity. up fo 1mA with respect to circuit Lo for full range inwt: 100% o"elxs"!Le caoaLli1iev. I" tile normal mode rhe outpue pol&ity'is oppbsice input polarity

0PEuTING ENVIRONMENT: 20°C eo 3O"C, 0% co 70% re-

lative humiditv. 1O'C fo 5O'C wieh derated soec-

Better than 0.1% for loads up to

sensieiviey

Circuit Lo to chassis ground; greater

1 vo1c: ?l volt at

ifications. s&age: ooc to 70°C.

CONNECTORS:

Analog outputs: Unity gain, 1 volt chassis, Lo. and guard; binding poses. BCD Output: co""eceors for interfacing ?he Node1 6162 Isolated OutpuflConCrol.

DIMENSIONS; WEIGHT: Style M 3-l/2 in. half-rack,

OVer811

15-314 in. deep (100 x 220 x 400 mm); "et weighC, 11 pounds (4,a kg).

POWER:

(switch selected), 50-60 Hz, 9 watts.

ACCESSORIES SUPPLIED: Model 6011 Input Cable: 3 ft.

(lm) rriaxial cable with triaxial co""ector and 3 auigaeor clips.

1npue:

bench size 4 in. high x a-314 in. wide x

Line Operario":

Teflon-insulated trisxial.

1neerna1

go-125 0r 180-250 volts

1

iv

0374

SECTION 1.

GENERAL INFORMATION

l-l. INTRODUCTION. The Model 616 Digital Electrometer is an automatic ranging, multipurpose electrometer featuring sensitivity to 10 microvolts per digit. Its 3-l/2 digit LED display provides 0.2% voltage accuracy for a wide range of measuremente.

The Model 616 is essentially a digital multimeter optimized for measurements from high source impedance. The 616 provides wide range capability when

measuring current, resistance, and charge in addition

to voltage.

1-2. WARRANTY INFORMATION. The warranty is stated an the inside front cover of the manual.

l-3. CHANGE NOTICE. Improvements or changes to the instrument not incoqmrated into the manual

will be explained on a Change Notice Sheet

attached to the inside back cover.

0773

1

GENERAL INFORMATION

MODEL 616

TABLE 1-l.

Front Panel Controls

Control Power ON SENSITI"ITY ZERO RANGE

FAST/NOW ZERO CHECK INPUT

Functional Description Controls line power. Sets voltage sensitivity and decimal paint.

Adjusts zero affset.

Sem range on a chosen function.

Sets instrument for either Feedback or Shunt Mode. Places instrument in ZERO CHECK mode. Triaxial input receptacle.

FAST/NORMAL

ZERO CHECK

Paragraph

--

3-4a 3-4a 3-3

3-7b

3-6 3-2a

s103

I

POWEk

ON

S202

SENSIiIVITY

s401 R119

FIGURE 2.

RANGE

SlOl

Front Panel Controls and Display.

n&AXIAL

INPUT 5120

0773

MODEL 616

TABLE 1-2.

Rear Panel Controls.

Conrrol

Line Switch

1v (RED) 3117

I

Functional Description

Sets instrxment

Mates with 3-wire

117V: 3/16A (FU-29)

234V: l/lOA (FU-40) Unity-gain ouqmt, zoov @ 1 lnA maximum. Recorder Output, 1" @ 1 mA full range. Guard Output. circuit LOW.

Chassis ground.

for nominal

line

cord.

117V or 234V.

Paragraph

2-3a 2-3~ 2-3b

3-2c 3-2c 3-2~ 3-2c 3-2~

-

1175

FIGURE 3. Rear Panel Connecears.

3

INITIAL PREPARATION MODEL 616

SECTION 2. INITIAL PREPARATION

Z-l. GENERAL. This section describes procedures far incoming inspection and preparation for use.

2-2.

INSPECTION.

The Model 616 was carefully inspected both mechanically and electrically before shipment.

Upon receiving the instrument,

check for any obvious damage which may have occurred during transit.

Report any damages to the shipping

agent.

PREPARATION FOR USE.

2-3.

8. Line Voltage.

Before power is applied check the position of the LINE switch (5201) on the rear panel.

50-60

Select the 117V position for operation from

Hz line voltages over the range 9OV to 125"

rms . Select the 234V position for operation fro,,,

50-60

Hz line voltages over the range 1SOV to 250" rms . Line voltages which are not cavered by ranges specified require an appropriate step-up or stepdawn pawer transformer.

b. Fuse Installation.

After the line "alrage range is selected check for the proper fuse type and rating 8% fallows:

117v:

234V:

c. Line Co""ectio"s.

3116 ampere, type 3AG

SLO-BLO (FU-29)

l/l0 ampere, type 3AG SLO-BLO (F"-40)

This instrument requires * three-wire line cord (Keiehley part no. CO-7) which provides connections t" line voltage (high, common) and chassis ground.

For operator safety, the chassis ground pin should be connected to earth ground.

CZ

If the instzxment input LO is to be floated, above chassis ground, make certain that the "link" between LO and GROUND on the rear

panel is removed.

d. Warm-up. The recommended warmup time far the Model 616 is two hours, although if is useable immediately after power is turned on, for less critical meas"reme"ts.

4

1175

MODEL 616

I

OPERATING INSTRUCTIONS

SECTION 3.

3-1. GENERAL. This section describes the procedures for operating the Model 616 for measurement of valr-

age, ~uccent, charge, and resistance. 3-2.

HO" TO MAKE INPUT AND OUTPUT CONNECTIONS.

a. Incut Receotacle. This receptacle is a Teflon insulated triaxial connector. The center terminal is the high impedance input; rhe inner shield is the law inout: and the outer shield ie case ground. The m&n; connector is a Keirhley part "0. CS-141 triaxia1 plug.

b. Model 6011 Input Cable. This cable is a 30 inch long triaxial cable terminated with 3 colorcoded alligator clips. The input high is identified

by the heavy wire with red insulator. The input

low is identified by the thin wire with black in-

sulator. The case ground is identified by the thin

wire with green insulator.

C. Rear Panel Terminals. The rear panel has six binding posts which are used for making special connections to the Model 616.

1. Xl Terminal (White). This terminal provides

an analo,q signal at unity gain. CAUTION Up to 200 volts my be present at this terminal.

2. 1" Terminal (Red).

an analog signal wivh a scale factor of 1 volt far

full range input.

3.

Lo Terminals (Black). These terminals provide a connection to input low. terminal may be used for system connections.

GUARD

4.

vides a connection to the amplifier feedback when in the FAST made.

5. GROUND Terminal (Green). vides a connection to chassis ground. A shorting link is provided for easy connections between lo" and chassis. For floating applications, the link must be removed.

Terminal (Blue). This terminal pro-

This terminal provides

Either

This terminal pro-

OPERATING INSTRUCTIONS

3-3.

HOW TO SELECT FUNCTION. a sinele front-"anel rotarv switch for selection of function and range. manual selection of any of four functions, namely,

VOLT, OHMS, COULOMB, and AMPERE.

3-4.

HOW TO "SE THE, VOLT FUNCTION. provides five decades of voltage sensitivity from

.OlOOO volts to 100 volts full range. The VOLT func-

tion is selected by setting the RANGE switch to VOLT.

a. Manual Sensifivity Setfin~s. The front panel SENSITIVITY switch has six positions. ks the switch is rotated counter clockwise, the sensitivity is

increased.

sensitivities of lOO.OV, lO.OOV, l.OOOV, .lOOOV, and

.OlOOOV as in Table 3-1. AUTO sensitiviry mode which enables either *"tomatic sensitivitv or remotely selected sensitivitv

(when used with the Model 6162). See paragraph 3-4~ for a complete explanation of

Senslriviey

Setting

I

10 nlv

100 nlv

10 1v v

100

*The display indicates OOO.OV at 200.0 volra input.

The three least significant digits will flash on

and off (blinking action) to indicate an over-

voltage condition.

read up to f201.7 volts with blinking action. Beyond f201.7 "olts the display will indicate 001.7 volts with blinking action.

Valtaae inputs ,q.reater than f200 volts are not r;comm&,ded-since damage to the instrument may result.

These positions correspond to full range

Voltage Sensitivity Settings

" 100.0 199.9 v*

The RANGE Switch (5101) permits

TABLE 3-1.

Full Range Maximum

Display Display

.01000 v .lOOO v f .1999 v

1.000 10.00 v V v f i f 1.999 19.99 v v

The display will continue to

The Model 616 provides

The Model 616

Position six is

AUTO

mode.

f .01999 v

the

0774

GROUND

FIGURE 4. Triaxial Input.

POLARITY ZERO

DUMMY

1, -

DECIMAL--I

FIGURE 5.

Typical Display on 10 mv Sensitivity.

3 DIGITS

LOVER-RANGE

5

OPERATING INSTRUCTIONS MODEL 616

b. Automatic Sensitivity Operation. In the AUTO mode, the Model 616 automatically selects the proper sensitivity in accordance with the following

rules.

1. Upranging. If the display reading is between O-l-S-0 and l-9-9-9 and the i""ut siwal is increased beyond l-9-9-9, the Model 616 auto-

matically up-ranges to the next higher (less sensitive) range.

The three least significant

digits sre blanked during range changing so ss

to prohibit incarrect readings from being dis-

played.

If the input signal exceeds t199.9 volts

the display will continue to indicate up to f201.7

volts but the three least significant digits will

flash on and off to indicate an over voltage condition.

2. Down ranging. If the display reading is

~-

at least O-I-S-O and the input signal is decreased,

the Model 616 automatically down ranges to the next lower (mare sensitive) range.

C. Remote Sensitivity Selection. When the Model

616 is used with the Model 6162 Isolaced 0uc"utl

. Control, the 616's voltage sensitivity may be cemerely selected.

The output connector on the rear panel of the 6162 provides four isolated control lines for the purpase of remote sensitivity progr*""i.*g.

3-2.

The lines are coded as shown in Table

The 616's front panel SENSITIVITY switch

must be set t" AUTO position.

TABLE

3-2.

Remote sensitivity Programmi"g Logic

Sensitivity

Control Lines

&CR*

K4

R2

Kl

I .01000 " .lOOO v

1.000

10.00

100.0

I: ", : :

” 1 0 v : 1 1 0' " 0 1 1 1

*NOTE

The Manual Range line MR is used to defeat the automatic sensitivity feature. When MR is open, the 616 returns to s"tomatic operatian. Logic 1 - open, Iogic 0 = closure to ground.

3-5.

PO" TO SELECT RANGE ON OHMS, COULOMB, AND AMPERE. The front panel KANGE switch (SlOl) provides selection of four functions, VOLT, OHMS, COULOMB, and AMPERE as

described in paragraph 3-3. For each function, a wide selection of ranges is provided; 8 ranges on

OHMS,

4

ranges "n COULOMB, and 11 ranges on AMPERE. Since

the SENSITIVITY switch is used in conjunction with the RANGE Switch, the actual number of usesble spans

is 12 decades on OHMS, 8 decades an COULOMB, and 11 on AMPERE.

NOTE (ON AMPERE FUNCTIONl On the 10qlA t" 10~4A ranges, the voltage beveloped must not exceed 2 volts, otherwise, overheating of s range resistor could result. As s result,

the

10 Volt and 100 volt sensitivity settings ate not recommended for lo-l1\ to

1O-4A ranges.

TO interpret a reading an OHMS, COULOMB, or AMPERE ranges both the digital display (with decimal location) snd the RANGE setti"g(powers of ten)shauld be cansidered.

For example, given a digital reading of 17.32 and a RANGE setting of 1O-7 AMPERE, the actual measured value would be interpreted ss 17.32 x lO-7

ampere.

Since the decimal point is moveable, it is important

to notice the position of the demimal point to determine the full range of the instrument. See Table 3-3 for typical range settings in the AMPERE function.

TABLE

3-3.

Typical Current Range Settings*

Input Range Se"Siti"ity Digital

current setting setting Display

*The current reading is interpreted by multiplying the display reading times the range setting. Other cucrents not show" can be measured by selecting the sppr"priste RANGE switch setting in decade steps from lo-1'A to lo-lA.

3-6.

HOW TO MEASURE VOLTAGE. The Model 616 can be used to measure voltages from ilO microvolts to i200 volts.

Although the Model 616 is useable as a gener-

al purpose digital voltmeter, it has certain charac-

teristics which enable reliable meas"rement~ from very-high source resistsnces. When used in the VOLT mods, the M el 616 has B" input resistance greater than 2 x 10%.

As a result, the loading of the source circuitry is relatively insignificant when compared to typical digital voltme-cers having LOS ohms input resistance. The Model 616 has 20 picofarads of shunt capacitance (not including the input cable capacitance),

since a large *"o""t Of capaci-

tance causes a slowing of response, the input capaci-

ty ,shauld be kept 8s small as possible.

a. Measurements From Very High Source Resistance. TO "se the Model 616 as a voltmeter, set the front pane1 controls as follows:

RANGE

-- VOLT SENSITIVITY -- AUTO FAST/NORMAL -- NOW

Connect a Model 6011 Triax Cable (or other shielded triaxial cable) to the INPUT receptacle. Keep cable length as short as possible to reduce the slowing effects of cable capacitance. The ser" control may need occasional adjustment to reduce any voltage offset which msy occur due to temperature variations.

To

resero the Model 616, set the ZERO CHECK switch to CHECK position and adjust the front panel ZERO control for a O-O-O-O display.

The Model 616 pravides a direct reading voltage display with automatic decimal point position and polarity.

6

0476

OPERATING INSTRUCTIONS

I

---------_ SOURCE

b. Measurements From Low source Resist.a”ce. TO "se the Model 616 for voltage measurements from low ~our'ce resistances, set the RANGE switch to the lo-l1

AMPERE position. In this mode, the Model resistance is reduced to 1011 ohms; as a result the electrometer will be lees sensitive to electrical noise pickup and input cable vibration. Voltage measurements can be made by following the same procedure given in paragraph 3-6a. The Model 616 can be used with the RANGE eet et any position be-

tween 10-11 AMPERE to 10-l AMPERE.

input resisLence can be determined by taking the reciprocal of the AMPERE setting. Significant loading error may result if the input reeisrsnce 18 reduced to less than 100x the source resistance.

C. Measuremenrs Above 200 Volts. The Model 616

can be used with accessory divider probes to measure

voltages up to 30 kilovolts. Range muse be set to VOLT.

1. Model 6102A Divider Probe (1O:l). This accessory extends the voltage mesauring capability of the Model 616 to 1000 volts. The inpa resistance is lOlo ohms. to 1000 volts. ory Model 6012 Adapter is needed LO mete the triaxial input with the UHF connector a" the probe.)

2. Model 6601A Divider (1OO:l). This accessory

extends the voltage measuring capability of the

Model 616 to 5000 volts. The input resistance is

lo7 ohms. The divider accuracy ia +0.01X.

3. Model 6103A Divider Probe (1OOO:l). This accessory extends the voltage measuring capability of the Model 616 to 30 kilovolts. The input resistance is 10" f5% to 30 kilovolta. an accessory Model 6012 Adapter ie needed to mate the triaxial input with the "HP connector on the probe.)

The divider accuracy is +4%

(To use the Model 6102A en acceee-

ohma.

The divider accuracy is

(To

uee the Model 6103A

i

ERROR DUE TO CIRCUIT LOADING

% ERROR =

616 input

The Model 616

100 R

R + RIN

-----------------’

I

ELECTI(OMETER

The Model 616 may exhibit a large amount of zero offset or drift immediately after an

overload or e long period of storage. I" addition, the offset current may exceed the

specification for a short time until the Model 616 ia sufficiently stabilized. Although the offset current of the Model 616

is well below offset found in conventional voltmeters, the effects of the offset current charging the input capscitance may be "ociced when the input is open. "se the ZERO CHECK switch to discharge the offset charge.

The Model 616 should "ot be operated with circuit low fleeting by greater than 1000 volta

with respect to chassis ground.

616 is to be used with circuit low floating

make certain that no connection is made be-

tween the LOW and GROUND terminals o" the

rear panel.

corder or other instrument to the Xl or 1V

outpute when the Model 616 is floated.

d. Voltage Measurements in FAST Mode. when the FAST/NORMAL Switch is eet to FAST, the Model 616 is connected in a "FEEDBACK" amplifier configuration. In this configuration, the Model 616 requires special connectians. between input HI and GUARD. A" easy way to accomplish this connection ie Lo connect the link (on the rear panel) between "GUARD" (blue terminal) and "GROUND" (green terminal). Then uee the rriaxial cable far input connectione with the input voltage

applied between the "red" clip lead and the "green" clip lead.

In this special voltage connection, the LO input (black clip lead) is "of used since the voltage amplifier Configuration has bee"

changed.

Do not connect a grounded re-

To measure voltage, co~ect the eource

NOTE

If the Model

1175

7

OPERATING INSTRUCTIONS

c------c--

l l

R R

I I

II--, II--,

I I

------F----------

l

MODEL 616

I I

MEASURING MXASURING

POINTS POINTS

I I I I

- -

i i

T T

: :

--WC---- --WC----

L L

; ; I I

_I’ _I’

SOURCE SOURCE

P1G"P.E 7. PICURE 7.

HOW To MEASURE CURRENT. The Model 616 can be

3-7. wed to measure currents from *lo-15 ampere to 200 mill***peres. a general purpose picoammerer, it has certain charac-

teristics which enable reliable measurements of very

small current8 with fast response.

a. Normal Mode Current mode for current below lo-5A.) I" this mode, the Model 616 measures current "ver a wide range. When

the FAST/NORMAL switch is set to NORMAL, the Model 616 operates as a shunt-type picaammeter in which a resistor is connected directly across the input terminals. acro.m the shunt resistors where VIN - IIN x RS. This method of measurement is typical of 'mast multimeter current measuring techniques. To use the Model

616 as a shunt-type pidoammeter, eat the front panel controls *s fallows:

RANGE

SENSITIVITY -- AUTO

PAST/NORMAL -- NORMAL

Full range is determined by the

sensitivity setting and the AMPERE range setting.

Connect a Model 6011 Triax Cable (or other shielded eriaxial cable) to the INPUT receptacle. Keep cable length as short as possible to reduce the slowing effects of cable capacitance. The zero control may need occasional adjustment to reduce any voltage

offset which may occur due to temperature variations. To rezer" the Model 616, set the ZERO CHECK switch to CHECK position and adjust the front panel Zero control for a O-O-O-O display.

Although the Model 616 is useable a8

Measurements.

The Model 616 measures the voltage drop

-- 10-5

AMPERE (or appropriate range)

NOTE

-

operation As A" hater in NORMAL Mode. operation As A" hater in NORMAL Mode.

(Use FAST

L1-__------------! L1-__------------!

ELECTROMETER ELECTROMETER

” = I x Rm ” = I x Rm

The Model 616 may exhibit a large em"u"t of

zero offset or drift immediately after a" overload or a long period of storage. I" addition, the offset current may exceed the specification far a short time until the Model 616 is sufficiently stabilized. Al-

though the offset current of the Model 616

is well below offset found in conventional voltmeters, the effects of the offset current

charging the input capacitance may be noticed when the input is open. Use the ZERO CHECK

switch to discharge the offset charge.

Do not use the 10 volt and 100 volt aensi-

tivity settings for RANG? switch settings of LO-~, 10e2, 10v3, and 10e4 ampere. the voltage ekeeds~2 volts on these ranges, averheating of the resistors could result

with subsequent degradation of accuracy in

the AMPERE mode.

If

0476

MODEL 616

OPERATING INSTRUCTIONS

b. Fast Mode C rrent Measurements.

currents from 10 A and smeller.) In this mode, the

-s

(Useable for

Model 616 measures very amall currents with fas; response. When the FAST/NORMAL switch is set to FAST, the Model 616 operates as a feedback-type picaammeter in which the current flows through the feedback resistor of the voltage amplifier. The Model 616 indicates the voltage developed across

the range resistor where VF =

method of measurement provides

I

Es: ~~p0~8*since

the effect of the input capacitance from lengthy

cables is diminished.

To use the Model 616 as a feedback-type picoammerer, set the front panel controls *s follows:

RANGE

-- lo-l1 AMPERE

SENSITIVITY -- AUTO

FAST/NORMAL -- FAST

Connect a Model 6011 Triax cable (or other shielded triaxial cable) to the INPUT receptacle.

The zero control may need occasional adjustment to reduce any voltage offset which may occur due to temperature "S.***t*O~S.

To rezero the Model 616, set the ZERO CHECK switch to CHECK position and adjust the front panel ZERO control for a O-O-O-O display.

The Model 616 may exhibit a large amount of

zero offset or drift immediately after an overload or a long period of storage. In addition, the offset current may exceed the

specificarion far a short time until the

Model 616 is sufficiently stabilized. Al-

though the offset current of the Model 616

is well below offset found in conventional voltmeters, the effects of the offset current charging the input capacitance may be hoticed

when the input is open. Use the ZERO CHECK

switch to discharge the offset charge.

2) Considerafions~When

Measuring

C&rent. When

using the Model 616 in either the NORMAL or FAST

nodes, there are certain considerations which ensure optimum performance.

In general, it is advantageous

to use the smallest possible value of shunt resis-

tance for a picoammeter.

Fir*t, small value resistors are of higher quality compared to large values with respect to accuracy, time stability, temperature. and voltage coefficient, Second, ideal picoammeters require very small input resistance so that source loading does not affect the overall accuracy of the measurement.

Since the input resistance

in a shunt picoammeter is determined by the range resistor, the RANGE multiplier should be set at the lowest value.

Third, the use of a low value resis-

tor reduces the input RC time constant and results

ln faster response.

Harever, since noise and zero

irift become more significant when the voltage

unplifier sensitivity is set to 10 or 100 millivolts,

the appropriate range multiplier should be selected

with a one volt full scale sensitivity. The use of

the Model 616 in the FAST made enables measurements of very small currents while reducing the source loading and input RC time constant. Since the range resistor is connected in the feedback of the voltage amplifier, the effective input resistance is determined by the open-loop gain where SIN = RF t A.

(The value of A is typically 10,000.) Another advantage of the feedback mode is the reduced effect of input capacitance since the input SC time copstant is decreased by the gain A (RCeFpECTIVE = RC i

As a result, the measurement speed is governed

A).

by the feedback time constant which is a function

of the feedback resistor and stray capacitance acT088 the resistor (usually a few pF). Thus, when comparing shunt versus feedback modes, it is evident that the feedback measurement offers superior performance for most applications.

TABLE 3-4.

HOW TO SELECT APPROPRIATE AMPERES RANGE.

urrent To

a Measured

lo-15A 10-14A lO:;;A 10 A

;;I:~

Range

Setting

10-11 g::: 10-11

$"

LO-' A

,ppropriate

LO-' A lO-7 A 10-6 A 1O-5 A

10-e 10-7

lo-6

10-5 1O-4 A 10-4 lO-3

A

10-3 1O-2 A 10-2 10-l A

10-l

Appropriate Sensitivity

Setting

10 In" 10 In" 10 mv

100 mv

1" 1v 1v 1" 1v 1v 1v 1v 1v 1v 1v

NOTE

-

.OOOlO x lo-1lA .OOlOO x 10-llA

:;;;p,xl;";:';

;:g; : ;$ ;

1.000 x lo-' A

1.000 x lO-8 A

1.000 x lO-7 A

1.000 x

lo-6

1.000 x 10-S A

1.000 x 10-4 A

1.000 x 1O-3 A

1.000 x 1O-2

1.000 x 10-l A

The we of the FAST mode for current measurements is subject to certain restrictions ae follars:

1. The range resistor value should not be greater than the source resistance, otherwise feedback division results in zero instability at

the output.

2. The largest value of current measured should not exceed 10e5 ampere, otherwise the full feedback current cannot be developed. The NORMAL mode should be used for currents from 200 mA to 10-4A.

A

3476

9

OPERATING INSTRUCTIONS

MODEL 616

r---------m

-1

I I

MEASURING

I %

I ..----,---,I

SOURCE

FIGURE 9.

3-8. HOW TO MEASURE RESISTANCE. be used to measure resistance from 1 ohm to 2 x 1014 ohms. Although the Model 616 is useable as a general purpose ohmeter, it has certain characteristics which enable reliable measurements of very large resiseances with fast response.

Up to 250 volts may be present at cerminale.

a. Normal Mode Ohms Measurements. Model 616 measures resistance over a wide range. The use of the NORMAL mode is recommended for measurements up to 1O'l ohms (use the FAST mode for larger resis-

tallces). The Model 616 uses a constant current method for measuring resistance. 16 proportional to the voltage developed across the

input terminals.where V = I x R (the current I is selected in decade steps using the RANGE Switch). To use the Model 616 as an ohmmeter, sac the front panel controls 88 follows:

RANGE

SENSITIVITY -- AUTO

FAST/NORMAL -- NORMAL

e***t**ce to

be Measured

lOl$ 1012n IOllQ $0;

109 0 108 n 10' n 106 n lo5 n 104 n 103 n lo2 n

-- 105 OHMS (or other appropriate range)

HO" TO SELECT APPROPRIATE ONMS RANGE.

Lppropriate

14

CAUTION

There, the digital readout

TABLE 3-5.

Range

Setting

;;::

1012 1011 1010 109 108 107 106 lo5 105 105 105

The

1v 1.000 x loL"n 1 " 1 v 11.000 1v 1.000 x 10' n 1v 1.000 x 106 n 1v 1.000 x 105 n 1 " .I""" x n 104

Operation As An Obrmneter in NORMAL Made

Model 616 can

In this mode, the

1.000 x log n x 10: n

x 1030 x 1o‘al

.--------------m-w.

INPUT

L---,--- ------ --,I

ELECTROMETER

" = I x Rx

Connect a Model 6011 Triax cable (or other shielded triaxial cable) to the INPUT recept&le. Keep cable length as short as possible to reduce,the slowing effects of cable capacitance. The zero control may need occasional adjustment to reduce any voleage offset which may occur due to the temperature "aria-

thl*.

switch t-0 CHECK position and adJust the front panel ZERO control for a O-O-O-O display.

Model 616 meaeures very large resistancea with fast

y$a

FAST, the unknown resistance (Rx) is floating with respect to the low side of the voltage ampli-

fier. feedback so as to reduce the effects of capacitance and therefore speed up the measuring time. TO use

the Model 616 for FAST ohmmeter measurements, see

the front panel controls as follows:

Connect the unknown resistance between input HI and

GUARD (on the rear panel).

I

To rezero the Model 616, set the ZERO CHECK

b. Fast Mode Ohms Measurement. In this mode, the

onse (use this mode for resistances larger than

ohms). When the FAST/NORMAL switch is set to

The unknown resistor is connected across the

RANGE -- 1012 OHMS SENSITIVITY -- AUTO FAST/NORMAL -- FAST

When the FAST mode is used for resistance measurements, the unknown resistance sample is connected in feedback around the electrometer amplifier.

floating and not referenced to LO.

Therefore the resistance must be

I

10 0476

r---------1

I

CHARGE

TRANSFER--t,

I I

n

,m----------- -----,

, INPUT

I

I +

' %/ I

I b---m-----?

3-v. HOW TO MEASURE CHARGE. The Model 616 can be

SOURCE

I

I I

I

MEASURING

POINTS

&

used LO measure charge by means of a current integration technique.

anyone of the 4 coulomb ranges, an accurately known

"hen the Model 616 is set to

capacitor is connected in the feedback loop of the voltage amplifier so chat the voltage developed is ~oportional to the integral of current where V =

'C or V = l/Ciidt. To use the Model 616 as a coul-

ombmeter, 8et the front panel controls as follows:

RANGE -- 10-10 COULOMB SENSITIVITY -- AUTO

FAST/NORMAL -- PAST

Connect a Model 6011 Triax cable ("r other shielded Lriaxial cable) to the

INPUT

receptacle. Keep cable length a8 short as possible to reduce the slowing effects of cable capacitance. The zero control may need occasional adjustment to reduce any voltage offset which may occur due to the temperature variatiO"S. To rezer" the Model 616, set rhe ZERO CHECK Switch t" CHECK position and adjust the front panel ZERO control for a O-O-O-O display.

NOTE

-

The input offset current of the Model 616 contributes a charge of 5 x lo-15 coulomb per second and should be subtracted- from

the actual reading.

The Model 616 can also be used with acces-

sory Models 2501 or 2503 for measurement af

static

charge 0" a dielectric surface.

A

discussion of static charge measurement is given in secrion 3-lla.

For m"re information about Static Charge

Measurements, request the Keichley PrOduct

Notes entitled "Electrometer Static Charge

Measurements”.

i

,Lc

I .-.------------____,

3-10.

HOW TO "SE AS A CURRENT SOURCE. The Model 616

ELECTROMETER

v = l/C /i dt

I

can be used as a current .s"urce for currents in decade increments from 10-5A t" lo-12A. TO select cur-

rent, set Model 616 to OHMS function. set OHMS range

to the appropriate position as show" in Table 3-6.

"se NORMAL mode for currents up to lo-loA, and FAST

made above lo-loA.

TABLE 3-6.

' Current Desired

lo-=A lo-"A 10-lOA lo-' A 10-S A 1O-7 A 1O-6 A lo+ A

OHMS Range

12 1011n $10;

IO9 n 1oS n 107 R 106 n lo5 R

When input to Model 616 is not connected, set Zero Check Switch t" CHECK. If no inp"f connection is made a large voltage

(up to ZOOV)

can appear across the input.

3-11. ALTERNATE MEASUREMENTS. The Model 616 can also be used with Keithley accessories which ex-

tend the measuring capabilities of the electrometer.

Static Charge Measwement~. The Model 616

a. can be used with Models 2501 or 2503 Static Detector Probes far measurement of static charge on a dielectric surface. When using this method, the Model 616 is operated as a voltmeter with a reading directly in volts.

(Do not attempt t" measure static charge

with the Model 616 in the COULOMB mode.)

1476

11

OPERATING INSTRUCTIONS

7’

L,

MODEL 616

I-

1

FIGURE 11.

b. Null Method for Current Measurements. The

Model 616 can be used with a" accurate current

source such as Keithley Model 261 t" measure small variations of current. When using this method,

the Model 616 is operated BB a current null detector

in the FAST mode.

justed to obtain a null reading "n the Model 616

(the electrometer shauld be set t" a" appropriate

range and sensitivity depending on the magnitude of

current variation).

Null Method far Current Measurement.

The current source should be ad-

I

C. volt-Ameter Resistance Measurements. The Model 616 can be used with a" accurate voltage source such as Keithley Models 240A, 244, 245, or

246. When using this method, the Model 616 is operated as a picaammeter so that the current through the unknown resistance is measured by the electrometer. terms of the knaun voltage impressed and the resultant current measured "n the electrometer.

Volt-Ammeter Resistance Method.

The resistance is then calculated iz

1 " OUTPUT = FULL RANGE INPUT

LO +--l--sJ

i LINK

CASE VC;;SE

FIGURE 14.

"se of 1V Recorder Output.

1

3-12. provides several outputs far monitoring a" analog signal.

used for monitorina the input sinnal in applications requiring a buffer-amplifi&. -

12

HO" TO "SE ANALOG OUTPUTS. The Model 616

a. Xl Output (Unity Gain). This ""tput can be

1. NORMAL MODE.

at the Xl OUTPUT (with respect to LO) is equal to

the input within 20 bpm at dc. The Xl OUTPUT can

deliver up tcJ 1 milliampere for Outputs up to 200

volts.

2. FAST MODE.

terminal is connected t" input LO. applications when inFAST mode the GUARD terminal should be used. current ranges is show" in Table 3-7. This data *a representative of instrument respanse for unity gain operation.

In the NORMAL MODE, the signal

In the FAST MODE, the X1 OUTPUT

For unity gain

Typical rise times for various

TABLE 3-7.

:sponse at GUA

Range

setting

.- .

*'ryplcal 1*strume*t perrormance <may vary tr"m unit

to unit).

b. 1 VOLT OUTPUT.

analog Output at up to,1 milliampere corresponding

to * full scale input.

RD (Unity Cain) OUTPUT for Fast Curre"

Rise Time

This "utput pravides a 1 volt

lo-90%

0774

MODEL 616 OPERATING INSTRUCTIONS

3-13.

provides isolated BCD outputs, remote controls, and remate pragramming lines for systems we of the Model

616. farmatian provided in parallel format. Strobe lines permit data transfer in 4 bit multiples which are

compatible with 8, 12, or 16-bit data eyeterns. Strobing of the “open collector” wtpute also permit multiplexing of data from 2 or more 6162’8 an e single data bus. l/5 second to 7 seconds per reading to permit a wanefer rate compatible with the speed of measurement end/or the acquigition system.

trole are provided for Zero Check, Sensitivity, Dfsplay Hold, Output Hold, ae well ae Strobe. The 616’s

low to chessis ground ie018tion is maintained by the 6162 (greater than lolo ohms). Digital w&put lcw

is also isolated from chassis ,ground by 10 ahme.

a separate 3-l/2 in. high half-rack chassis. be used on the bench adjacent to the 616 or reck mounted side-by-side in a standard 19 inch rack width using rack hardware provided (Model 1007).

HOW TO USE MODEL 6162.

8. General.

The Made1 6162 has 32 bite of meaeurement in-

Installation.

b.

Bench Mounting. Position the Model 6162 on

1. the left side of the Model 616 as shown in Figure 19 since the intercanneoring cable has been desighed to mate with the 616 in this configuration only. the sides which are adjacent. Loqeen the socket

head screw (Item 24) and elide the panqle to the

rear of the instruments. After both panels are remaved install the “mounting clamp” (Item 23)

Remove the “side dress” panels (Item 11) on

The Model 6162 Isolated Output/Control

Print rate can be adjusted from

Isolated Remote Con-

The 6162 circuitry is housed in

*e can

FIGURE 15.

using the original hardware. Remove two ecrewe

on one of the instruments and insert the mounting

clamp behind the corner bracket ae shown in Figure

17. Replace and tighten the two ecrewe to hold the clamp in place. the clamp behind the corner bracket on the second

i*stTXlE*t. Attach a l-l/L?” long Phillips head

ecrew (Item 25) and kepnut (Item 26) to secure the two instruments together.

2. Rack Mounting. Proceed 88 described in the

above paragraph for bench mounting. The,, attach a,, “angle bracket” (Item 21) on each instrument using hardware (Item 22) in place of original hardware. The battam corner feet and tilt bail assemblies may be removed if necessary. The original hardware, side dress panels, feet and tilt bail aeeemblies should be retained for future conversion back

to bench mounting.

Front Panel af Model 6162.

Next, insert the open part of

FIGURE 16.

Dual Rack Mwnting Ueing Model 1007 Hardwarr.

OPERATING INSTRUCTIONS

MODEL f

c. Connections.

FIGURE 17.

A single prewired cable plugs

Rear Panel of Model 616 and 6162.

e.

Summary of Digital Information. Table 3-10 into the 616's chassis to provide all necessary identifies the data lines available et the 6162 communication between units. To install the cable, remove the 616's top cover, place rubber grommet

output connector.

The data ia grouped in 4-bit

bytes with a corresponding Strobe line. The strob within the rear panel slot, insert cable, and plug (or enable) line permits serial data transfer from the three mini-connectors into their respective pc-board locations as shown in Figure 19.

A separate

a single 6162 or multiplexing of the data output o

a number of 6162's anta a common data bus. Conven 50-pin AMP type 205211-l connector provides isolated tianal parallel data transfer is obtained when all outputa and control lines. A mating 50-pin connector is furnished with the 6162 (Keithley Pare No. CS-271).

d. Power Requirements. The 6162 is powered from

50-60Hz line voltage and has a separate power switch

and fuse. Line voltage is selected using the rear

panel switch. Fuse type is 3AG SLO-BLO, l/SA.

strobe lines are at Logic "0" (closure to output L

within 0.5 volt).

f.

Print Rate.

The basic 616 has a reading rat of 5 readings per second. The front panel RATE control on the 6162 varies the print rate in l/5 second increments.

INTEKCONNECTION CABLE

REAR PANEL MODEL 6162

10 PIN CONNECTOR PIN ., ON THIS CONNECTOR IS OPEN (NO CONNECTION)

10 CONNECTOR

PIN B ON THIS CONNECTOR IS OPEN (NO CONNECTION)

14

10 CONNECTOR

5 PIN

CONNECTOR

PIN C ON THIS CONNECTOR IS OPEN (NO CONNECTION)

10 PIN CONNECTOR

IS OPEN (NO CONNECTION)

FIGURE 18. Diagram of Interconnection Cable Between 616 end 6162.

05

MODEL 616

OPER&NG INSTRUCTIONS

SPECIFICATIONS; MODEL 6162

TABLE 3-8.

IIGITAL OUTPUT: BCD (8421) open collector logic re-

presente each Of 3 digits (0 = "OOOO"), overrange digit, uprange ("O"), palarity (+ = "l"), decimal position (5 lines), exponent (5 line, BCD), exponent polarity (+ = "I"), downrange ("O"), zero check

("I"), and function (2 bit code).

rCCURACY :

quiva1ent to 0.1% of range).

QAG (FLAG): Logic "1" ("0") from 50 milliseconds to

fl digit with respect to 616 display (e-

-

7 eeconde depending a" Print Rate setting. No change in Digital Output is made during this interval.

l"TP"T LOGIC LEVELS:

0"tp"f Logic "1" : open collecear to autput La. output Logic "0" : closure to output LO.

Output Device: MC858P or equivalent

(greeter than 6V breakdown, 0.5V et +35mA sink).

!S-fOTE CONTROLS:

Zero Check: Logic "0" act"ates 616 Zero Check. Sensitivity: 4-line code far remete eeneitiviey

setting of 616.

Display Hold: Logic "0" retains last reading on

display (except polarity).

Output Hold:

Logic "0" retains data from last read-

ing at Digital output.

Strobe: 8 lines for seriaIizing in multiples af 4

bite.

Logic "1" inhibits controlled output lines.

CONTROL LOGIC LEVELS: Logic "1" = either a" open

circuit or a voltage between +2 and +12 volta re-

ference to autput LO. Logic "0" E closure to ouep"f Lo within 0.5 volt while sinking 2.5 milliamperes.

PRINT RATE: Variable via front panel control from

l/5 second per reading to 7 seconds per reading in l/5 second increments.

ISOLATION:

Input LO to output Lo: sufficient to maintain 616 isolation specifications except adds 200 picofarads capacitance. Output Lo to chassis ground: farad.

greater than lo* ohms shunted by 0.1 micrc

Input may be floated up to flOO0 volts with respect t0 chassis grand. Output Lo may be flaated up t" tlO0 volts with respect LO chassis ground.

CONNECTORS:

Input: Attached cable cennecte a, 616. Output: 50-piq AMP type 205211-l. Mating co""ectar supplied.

ENVIRONMENT: Operating:

10°C t0 5ov, 0% to 70% re-

lative humidity. Storage: O'C to 70"~.

POWER:

90-125 or 180-250 volts (switch selected),

50-60 Hz, 9 watts.

DIMENSIONS, "EIGHT: Style M 3-l/2 in. half-rack,

overall bench size 4 in. high x B-314 in. wide x

15-314 in.

deep (100 x 220 x 400 mm). Net weight,

7 pounds (3,2 kg).

ACCESSORIES SUPPLIED: Model 1007 Dual Rack Ma,neing

Kit.

8. Da.8 Transfer.

Conventional parallel data

transfer is accomplished through parallel connections

with one bit of information per conductor.

Serobing allows data to be grouped into word lengths (bytes) appropriate te the acquisition device. thus simpli-

fying the interfacing between the 6162 and 8, 12, or

._..

lb-tat devlcee. when a11 STROBE lines are at Logic "0". the 6162 data outputs are enabled end ere sveil-

able in parallel farm. Individual strobe lines may be used to c~nlect te e cemmen data bus in multiples of l-bit words.

The 6162 "open-collector" ~utpute

are "open" unless the respective strobe lines ere at Logic "0". The uee of "open-callactor" configuration allawe the parallel connection of 2 or m"re

6162 unite since none of the outputs will conduct unless strobed. The 6162 wtpute ere TTL and DTL compatible.

The "open callectar" output switches between a high and low impedance level rather the" specific voltage levels. determine the voltage level defined by logic state

,tl,,

The output "1" etete may be selected fram any

.

This permits the ueer to

voltage over the range of +2 and +12 volts. The "0"

state is 0.5V et +35 m.4 (maximum)sink current.

h. Word Sequence. The pa,rticular sequence in

which the worda appear in serial data transfer is

determined by the way the "STROBE" lines are grouped and the order of ectiveti"", in addition to the

wiring of the data blocks.

i. Control Features.

1. Flag (m. This eutp~t provides a lagic

level which ce" be used to indicate the proper

time interval for transfer of data. A logic "1"

~ccure from 50 milliseconds ta 7 seconds depending

on the Print Rate contra1 setting. Na change in the Digital Output is made during this interval. On some digital devices, it may be necessary to trigger off the leading edge of the Flag or Flag

-

waveform by differentiating or other wave shaping.

2. Display Hold.

This control line retains the last reading on the display (except polarity) when closure is made te digital LO (Pi" 4). Neither the a/d conversion "ar digits1 wtput ere affected by fhie control.

3. Output Hold. This control line retains the

last reading et the Digital Output when closure is

made to digital LO (Pin 4). Neither the a/d converaia" nor digital display ere affected by this

control.

4. Zero Check. This contra1 line e&uetee the 616's zero check solenoid to permit monitoring of the electrometer amplifier offset. When the line ia released (Logic "1") the 616 returns te "o-1 operating canfigl+ti0n. ~The front panel ZERO CHECK awitch muet be set te OFF position te penoit remote zero check control.

j. Remote Programming. Remote lines ere provided at the 50-vi" connector to Kermit rem"te selection of se"sit&ty over five decedes. When the 616's

SENSITIVITY Switch is eet to

AUTO

position, the seneitivity may be remotely programmed or allared to function automaticslly. When the MANUAL RANGE line on the 6162 is et Logical "0" the coded range lines are enabled, and the LSI range linea ere disabled.

1175

15

OPERATING INSTRUCTIONS

MODEL 616

N8”e

Strobe Ul Fl

F2 EXP POL

EXP 1 x lo1

1 x 10' 17 2 x 100 12 4 x 100 11 8 x 10' 16

1 x 102 30 2 x 102 25 4 x 102 26 8 x lo2 24

Strobe #6

Pin No.

I

48

I

19 Buffer Control

I

DR UR 9

I

a

Cross-Reference for Digital 0utp"ts.

Remarks

Buffer Control Coded function lines

See Table 3-12

t

Logic "1" - +

Buffer Control

Used on OHMS, AMPERE,

COULOMB ranges

Buffer control for

Data 111

I

Data 111 (BCD)

t

Buffer control for

Data 112

Data 112 @CD)

t

Buffer control for

Data u3

Data #3 @CD)

t

Dmm Range

UP Range

TABLE 3-9.

Strobe #7

FLAG FLAG

Strobe 88 Zero Check

1 x 103 POLARITY DPl

"0" (10 mv range)

Strobe 1/9 39 DP2

DP3 5 DP4 6 DP5 23

The following are not strobed.

Output Hold

Display Hold

MANUAL RANGE

3 32

R2 14

84 33

Digital Lo

Zero Check

Name

Pi" No.

3

27 10

20 13

21 43

4:

22

2

50

I

31

4

15 Remote Control

Buffer Co"rrol Timing OUtput

Timing Output

Buffer Control

Indication overrange output Logic "1" - +

Dummy Zero

Buffer Control

Remote Control

sensitivity lines

-See Table 3-13

Ground Reference

Remarks

.ooooo- 10 m"

.oooo= 100 "V o.ooo- 1 " oo.oo= 10 " ooo.o- 100 "

16

FIGURE 19.

Identification of Pins O" Digital Output Connector.

0476

MODEL 616

OPERATING INSTRUCTIONS

--.

Pi" N,

0. Name I

1

2 3 4 5 6 7 8 9

10

1%

11 12

13 14 15 16 17

18 19

20

21

-1x103~-~ 22 23 24 25

I

Strobe

output Strobe

output

DP3

114

Hold Control /17 Buffer Control

LO GND

(l.ooo)*

DP4 (lo.oo)* DPl (.OlOOO)*

Buffer Control

Decimal Point Decimal Point Decimal Point

DR

1 up-range

FLAG

4 x 100 2

x 100

ZERO CHECK

R2

ZERO CHECK

8

x 10"

1 x 100 Strobe 1/5

Strobe ,,6 Strobe It8

DP 2 (.looo)*

DP5

(lOO.O)* Decimal Point

8 x lo2 2 x 102

Timing Outwt

tuta Ill

Dsra 111 output

Range Control Remote Control

Data #I

Data 01 Buffer Control

Buffer Control Buffer Conrr&

Data i/4

Decimal Point

Data 113 tuta II3 50

pin-out for 50-P*" Co""eCtor

TABLE 3-10.

Functio"

Pin No. Name

I

26

1 27 / FLAG ,

28

I

29

30 31

32

1 34

35 36

37 38

I dP 8 x 10:

39 Strobe #9

40

41 ::

44 45 46 47 48

49

Function

I

4

x

loL

4 x 101 2 x 101

1 x 102 MAN"AL RANGE

Rl

Data 113

/

I Timing 0"fpue

Data j2

Data 1/z

Data #3

Range Control

I oum,ut I

EKP 4 x 10" Strobe 03

EKP 1 x

100

Exe 2 x 100

output Buffer Control Output

output

Buffer Control "0" (IO "" range) RKP POL

101 EKP 1 x POLARITY

Fl

F2~ 8

101

x

101

1 x Strobe It1 Strobe ,,2

output output

output Output

FUnCtiO”

Func eion IkIt* 112

Data /12 Buffer Control Buffer Control

Display Hold Control

I

t--

,

Decimal Number

n = 0,1,2,3, or 4 depending on digit being decoded.

TABLE 3-12.

Truth Table for Function

Function

Function OHMS

OHMS

COULOMB

COULOMB AMPERE

AMPERE VOLT

VOLT

rT---!

0 1

F1

0 0

1 0

0 1

0

1 1

TABLE 3-11.

Truth Table for 8-4-2-l SCD Code

2

8 x 10"

4

x 10"

x 10" 1 x 10"

(4th bit) (3rd bit) (2nd bit) (1st bit)

0 0

0

1

TABLE 3-13.

Truth Table for Programmed Sensitivity

MWl”81

0 0 0 0 1 0 0 1 0 0 0 1 0 0 0 0

F2

Sensitivffy R*“ge

.Ol .Ol .Ol .Ol

1

.l

1.

10.

100.

R4

0

1 1 1

R2

0

0 0 0 1

1 1 1

Rl

0

1

1 0

1175

17

OPERATING INSTRUCTIONS MODEL 616

Truth Table for Serial Transfer

TABLE 3-14.

I,8

STR BE 6

8 9

I

1

,I

STROBE 7

19

3

27 10 I

L

,I

0

4 t Y c A 6 C II

FIGURE 20. Suggested Hook-up far Data Lines.

1175

REMOTE

t5V

"CN"

16 A-O SIGNALOV

+5v

BUFFER

STORE OV I

+5v ;

(DELAY) Ov ;

COUNTER

FLIP-FLOP

RESET OV

+Yl

RESET OV I

t5v

t5V

FLAG

ov

A

MODEL

616

I

I I

I

, MODEL

BCD

6162

A \+-

\1 A’-

1 ‘-IS~o$~;ON-’ 1

ISOLATION

lo’“cL, 1ooov

FIGURE 21. flack diagram of 61616162 System.

2016 COUNTS "COUNT NOW"

1lOOV

I

ISOLATION lo%, 1oov

2016 COUNTS

"COUNT NOW"

, DIGITAL

SYSTEM

:

HOLD activated and deactivated on the rising edge of "CN" tmmediately following application of user's "HOLD"

signal.

NOTE: The hold command is activated (or deactivated) on the rising edge of "CN". This means that when the

user applies the "HOLD" signal, the "HOLD" will not became effective until the conversion in process is finished and the data is stored in the output buffers. "HOLD" line, "HOLD" will not become effective until after the rising edge of the next "FLAG" signal. For this reason, the first "FLAG" after "HOLD" is released should be ignored and the data buffers will not be updated on the first "FLAG" after "HOLD" is released.

FIGURE 22.

Timine Diaeram for 6162 Oumuts.

This also means that when the user%leases the