Hp 6826a Service manual

BIPOLAR

POWER

SUPPLY/AMPLIFIER

MODELS

6826A

AND

6827A

Valuetronics

Internationa

1

-

8

0

-

OPERATING

AND

SERVICE

MANUAL

FOR

SERIALS

1317A-00101

AND

ABOVE*

*For

Serials

Above

1317A-00101

a

change

page

may

be

included.

HEWLETT-PACKARD

Part

No.

5950-1702

Printed:

November,

1974

SECTION

I

GENERAL

INFORMATION

1-1

DESCRIPTION

1-2

This

instruction

manual

contains

operating

and

service

instructions

for

two

Bipolar

Power

Supply/Amplifiers

(Models

6826A

and

6827A).

The

Bipolar

Power

Supply/

Amplifier

(BPS/A)

is

a

general

purpose

instrument

useful

in

any

laboratory

engaged

in

the

research

and

development

of

electronic

systems,

circuitry,

or

components.

The

BPS/A

can

be

operated

as

a

power

supply

or

as

an

amplifier.

Ter¬

minals

on

the

rear

terminal

strip

permit

access

to

various

in¬

ternal

control

points

to

further

expand

the

operational

cap¬

abilities

of

the

unit.

The

resulting

flexibility

lends

the

BPS/A

to

an

almost

unlimited

number

of

applications.

Some

of

these

applications

are

outlined

in

Section

ill

of

this

manual.

The

following

paragraphs

describe

some

of

the

features

of

the

BPS/A

as

a

power

supply

and

as

an

amplifier.

1-3

POWER

SUPPLY

FEATURES

1-4

The

unit

can

be

made

to

function

as

a

regulated

dc

power

supply

by

setting

the

front

panel

MODE

switch

to

the

POWER

SUPPLY

position.

The

supply

can

furnish

either

a

Constant

Voltage

output

or

Constant

Current

out¬

put.

The

dc

output

is

bi-polar

and

is

continuously

adjustable

from

its

maximum

rated

positive

value

to

an

equal

negative

continuously

through

zero.

A

crossover

feature

automati¬

cally

changes

the

supply

from

constant

voltage

to

constant

current

operation

at

a

preset

or

programmed

voltage/current

point.

The

front

pane!

CURRENT

MODE

indicator

lights

for

constant

current

operation.

Both

the

supply

and

the

load

are

protected

against

overvoltage

and

overcurrent

conditions

by

internal

circuits.

Dual

output

voltage

ranges

are

provided

for

better

resolution.

The

front

panel

RANGE

switch

allows

selection

of

the

high

(X10)

or

low

(XI)

output

range.

1-5

The

output

voltage

can

be

programmed

locally

using

the

front

panel

VOLTAGE

control,

or

remotely,

by

means

of

a

resistance

connected

to

the

appropriate

rear

ter¬

minals.

The

output

current

can

be

programmed

locally

us¬

ing

the

front

panel

CURRENT

control,

or

remotely,

by

means

of

a

resistance

or

voltage

source

connected

to

the

appropriate

rear

terminals.

The

BPS/A

can

be

programmed

(controlled)

at

a

very

high

rate

of

speed

(less

than

BOpsec

for

output

voltage

change

over

the

entire

voltage

span).

Local

and

remote

programming

connections

are

described

in

Section

III.

The

output

voltage

and

current

ranges

are

as

follows;

Model

6826A:

-5V

to

+5V

at

0

to

1.0A

(low

range)

--50V

to

+50V

at

0

to

1.0A

(high

range)

Model

6827A:

-10V

to

+10V

at

0

to

0.5A

(low

range)

-100V

to

+100V

at

0

to

0.5A

(high

range)

1-6

The

BPS/A

can

sink,

as

well

as

source

current,

per¬

mitting

it

to

serve

as

a

variable

load

device.

The

BPS/A

can

sink

up

to

50%

of

the

rated

output

current.

1-7

AMPLIFIER

FEATURES

1-8

The

unit

can

be

made

to

function

as

a

variable

gain

or

a

fixed

gain

amplifier

by

setting

the

MODE

switch

to

the

VAR

GAIN

AMP

or

FXD

GAIN

AMP

position.

When

oper¬

ating

as

an

amplifier,

the

BPS/A

can

amplify

externally

applied

ac

or

dc

signals.

Variable

gain

can

be

controlled

locally

(VOLTAGE

control)

or

remotely

and

is

accurate

to

0.1%.

The

variable

or

fixed

gain

provided

is

as

follows;

Model

6826A:

Variable

Gain

Fixed

Gain

Model

6827A:

Variable

Gain

Fixed

Gain

0-2

(low

range),

0-20

(high

range)

IX

(low

range)

10X

(high

range)

0-4

(low

range),

0-40

(high

range)

2X

(low

range),

20X

(high

range)

1-9

The

variable

gain

amplifier

is

non-inverting

and

has

a

frequency

response

from

dc

to

15kHz.

The

fixed

gain

amplifier

is

inverting

and

has

a

frequency

response

from

dc

to

40kHz

(6826A)

or

from

dc

to

30kHz

(6827A).

Total

harmonic

distortion

is

0.1%

(maximum).

1-10

METERS

1-11

A

voltmeter

and

an

ammeter

on

the

front

panel

monitor

the

ac

or

dc

output

voltage

and

current

respective¬

ly.

Associated

front

panel

VOLTAGE

METER

and

CUR¬

RENT

METER

switches

allow

the

meters

to

monitor

either

an

ac

or

dc

output

and

also

provide

dual

range

monitoring

capability

for

better

resolution.

The

dc

meter

accuracy

is

±3%

of

full

scale

and

the

ac

meter

accuracy

is

±5%

of

full

scale.

1-12

SPECIFICATIONS

1-13

Detailed

specifications

for

the

two

models

are

given

in

Table

1-1.

1-1

Table

1-1.

Specifications,

Models

6826A

and

6827A

NOTE

Specifications

apply

to

all

models

unless

otherwise

specified.

GENERAL

SPECIFICATIONS

Input

Power:

Model

6826A:

104-127/208-254Vac

(switchable),

48-63Hz,

1.0A,

130W

Model

6827A:

104-127/208-254Vac

(switchable),

48-63Hz,

1.2A,

150W

Meters:

Individual

voltage

and

current

meters.

DC

accuracy

is

3%

of

full

scale.

AC

accuracy

is

5%

full

scale

with

sinu¬

soidal,

100Hz

input.

Meter

Ranges

(DC):

M

o

del

6826

A

:

±6V,±60V

±0.12A,

±1.2A

Model

6827

A:

±12V,

±120V

±0.06A,

+0.6A

Meter

Ranges

(AC):

Model

6826A:

4V

(uncal),

40V

rms

0.08A

rms,

0.8A

rms

Model

6827A:

8V

(uncal),

80V

rms

0.04A

rms,

0.4A

rms

Temperature

Ratings:

Operating:

0

to

55°C.

Storage:

--40

to

+75°C,

Cooling:

Convection

cooling

is

employed.

The

supplies

have

no

moving

parts.

Dimensions:

See

outline

diagram.

Figure

2-1.

Weight:

18

lbs.

(8.2

kg.)

net,

21

lbs.

(9.5

kg.)

shipping.

POWER

SUPPLY

SPECIFICATIONS

DC

Output:

Voltage

and

current

spans

indicate

range

over

which

output

may

be

varied.

Model

6826

A

:

XI

Range:

—5V

to

+5V,

0

to

1.0A

X10

Range:

-BOV

to

+50V,

0

to

1.0A

DC

Output

(Continued):

Model

6827A:

XI

Range:

-10V

to+10V,

0

to

0.5A

X10

Range:

-100V

to

+100V,

0

to

0.5A

Load

Effect

(Load

Regulation):

Voltage

load

effect

is

given

for

a

load

current

change

equal

to

the

current

rating

of

the

supply.

Current

load

effect

is

given

for

a

load

voltage

change

equal

to

the

voltage

rating

of

the

supply.

Model

6826A:

Voltage

(XI

Range):

0.01%+.5mV

Voltage

(XI0

Range):

0.01%+

ImV

Current:

.01%

+

250/iA

Load

Effect

(Load

Regulation)

Continued:

Model

6827A:

Voltage

(XI

Range):

,01%

+

.3mV

Voltage

(X10

Range):

.01%+ImV

Current:

,01%

+

250

/kA

Source

Effect

(Line

Regulation):

For

a

change

in

line

voltage

between

104

and

127Vac/

208

and

254Vac

at

any

output

voltage

and

current

within

rating.

Model

6826A:

Voltage

(XI

Range):

.01%

+

.5mV

Voltage

(X10

Range):

.01%

+

5mV

Current:

.01%

+

250pA

Model

6827A:

Voltage

(XI

Range):

.01%+

ImV

Voltage

(XI0

Range):

.01%+10mV

Current:

.01%

+

250/uA

PARD

(Ripple

and

Noise):

Rms/p-p

(20Hz

to

20MHz)

at

any

line

voltage

and

under

any

load

condition

within

rating.

Model

6826A:

Voltage

(XI

Range):

2mV

rms/IGmV

p-p

Voltage

(X10

Range):

6mV

rm$/35mV

p-p

Current:

8mA

rms/5mA

p-p

Model

6827A:

Voltage

(XI

Range):

2.5mV

rms/15mV

p-p

Voltage

(X10

Range):

lOmV

rm$/50mV

p-p

Current:

.4mA

rms/5mA

p-p

1-2

Table

1-1.

Specifications,

Models

6826A

and

6827A

(Continued)

POWER

SUPPLY

SPECIFICATIONS

(Continued)

Model

6826A:

Temperature

Coefficient:

Voltage

(XI

Range):

lOmV

Voltage

(X10

Range):

lOOmV

Current:

3mA

Output

change

per

degree

Centigrade

change

in

am-

Model

6827A:

bient

following

30

minutes

warm-up.

Voltage

(XI

Range):

20mV

Model

6826A:

Voltage

(XI0

Range):

200mV

Voltage

(XI

Range):

,01%

+

.35mV

Current:

1.5mA

Voltage

(X10

Range):

.01%

+

3mV

Current:

.02%

+

50juA

Output

Impedance

(Typical

to

50kHz);

Mode!

6827A:

Approximated

by

a

resistance

in

series

with

an

indue-

Voltage

(XI

Range):

.01%

+

.7mV

tance

(constant

voltage

operation).

Voltage

(XI0

Range):

.01%

+

6mV

Model

6826A:

1m£2&1.5qH

Current:

.02%

+

50juA

Model

6827A:

2mft

&

4/uH

Drift

(Stability):

DC

Output

Isolation:

Supply

may

be

floated

at

up

to

300V

above

ground.

Change

in

output

(dc

to

20Hz)

over

8

hour

interval

under

constant

line,

load,

and

ambient

following

30

Remote

Resistance

Programming:

minutes

warm-up.

Mode!

6826A

(Resistance

Coefficient):

Model

6826A:

Voltage

(XI

Range):

2000H/V

±

.1%

Voltage

(XI

Range):

.03%

+

1

mV

(Pot

wiper

jump

Voltage

(XI0

Range):

200£2/V

±

.1%

effect

may

add

5mV)

Current:

10£2/mA

+

.1%

Voltage

(X10

Range):

.03%+

lOmV

(Pot

wiper

Model

6827A

(Resistance

Coefficient):

jump

effect

may

add

50mV)

Voltage

(XI

Range):

1000H/V

+

.1%

Current:

.1%

+

200;uA

(Pot

wiper

jump

effect

may

Voltage

(XI0

Range):

lOOft/V

±

.1%

add

1.5mA)

Current:

10£2/mA±.1%

Model

6827A:

Voltage

(XI

Range):

.03%

+

2mV

(Pot

wiper

jump

Remote

Programming

Speed:

effect

may

add

5mV)

50/isec

are

required

to

change

between

1%

and

99%

of

Voltage

(X10

Range):

.03%

+

20mV

(Pot

wiper

the

maximum

+

and

—

voltage

limits.

jump

effect

may

add

lOOmV)

Current:

.1%

+

200,uA

(Pot

wiper

jump

effect

may

Remote

Programming

Temperature

Coefficient:

add

1mA).

Output

change

per

degree

Centigrade

change

in

am-

Load

Effect

Transient

Recovery

(Load

Transient

bient

using

an

external

control

resistor

(Rp)

at

output

voltage

(Vo)

or

current

(lo)-

%

T.C.

Rp

is

the

tern-

Recovery):

perature

coefficient

of

the

control

resistance

Rp.

Time

required

for

output

voltage

recovery

to

within

Model

6826A:

the

specified

level

of

the

nominal

output

voltage

Voltage

(XI

Range):

,25mV

+

.007%

(Vo)

+

following

a

change

in

output

current

equal

to

the

%

T.C.

Rp

(Vo

+

5}

current

rating

of

the

supply.

Voltage

(X10

Range):

2.2mV

+

.007%

(Vo)

+

Model

6826A:

%

T.C.

R

F

(V

0

+

50)

IQOpsec

is

required

for

output

voltage

recovery

Current:

.016%

(Iq)

+

33pA

+

%

T.C.

Rp

(l

0

)

within

50mV

of

nominal

output

voltage.

Model

6827A:

100/usec

is

required

for

output

voltage

recovery

Model

6827A:

within

lOOmV

of

nominal

output

voltage.

Voltage

(XI

Range):

,5mV

+

.007%

(Vq)

+

Resolution:

%

T.C.

Rp

(Vq

+

10)

Voltage

(X10

Range):

4mV

+

.007%

(Vo)

+

Typical

output

voltage

or

current

change

that

can

be

%

T.C.

Rp

(Vq

+

100)

obtained

using

front

panel

controls.

Current:

.016%

(Iq)

+

33/tA

+

%

T.C.

Rp

(Iq)

1-3

Table

1-1.

Specifications,

Models

6826A

and

6827A

(Continued)

POWER

SUPPLY

SPECIFICATIONS

(Continued)

Sink

Current

Compliance:

Maximum

current

that

the

supply

can

sink

when

con¬

nected

to

an

active

load.

Model

6826A:

Sink

current

is

limited

to

a

value

ranging

linearly

from

1A

@

OV

to

.5A

@

50V.

Externally

applied

voltages

to

output

terminals

in

excess

of

GOV

could

damage

the

instrument.

Model

6827A:

Sink

current

is

limited

to

a

value

ranging

linearly

from

,5A

@

0V

to

.25A

@

100V.

Externally

applied

voltages

to

output

terminals

in

excess

of

125V

could

damage

the

instrument.

POWER

AMPLIFIER

SPECIFICATIONS

Output:

Mode

l

6826A:

Voltage

(XI

Range):

10V

p-p

Voltage

(XI0

Range):

100V

p-p

Current:

1A

peak

Model

6827A:

Voltage

(XI

Range):

20V

p-p

Voltage

(X10

Range):

200V

p-p

Current:

,5A

peak

Voltage

Gain

(High/Low

Range):

Model

6826A:

Fixed

Amplifier

(Inverting):

10X

(high

range)/

1X(iow

range)

Variable

Gain

(Non-inverting):

0-20

(high

range)/

0-2

(low

range)

Model

6827A:

Fixed

Amplifier

(Inverting):

20X

(high

range)/

2X

(low

range)

Variable

Gain

(Non-Inverting):

0-40

(high

range)/

0-4

(low

range)

Frequency

Response

(+1,

—3dB

at

full

output):

Model

6826

A

:

Fixed

Gain:

dc

—

40kHz

Variable

Gain:

dc—15kHz

Model

6827A:

Fixed

Gain:

dc

—30kHz

Variable

Gain:

dc—15kHz

Distortion:

Total

harmonic

distortion

is

.1%

(maximum)

at

100

Hz

and

full

output.

Input

Impedance:

lOKfi

(Typical)

Fixed

Gain

Accuracy

(at

100Hz):

Model

6826A:

Low

Range

(XI):

.1%

+

.5mV

High

Range

(X10):

.1%

+

5mV

Model

6827A:

Low

Range

(XI):

,1%+lmV

High

Range

(X10):

.1%+10mV

Remote

Resistance

Programming

Variable

Gain

{Ay):

KR

f

Ay

~

-

—

———

-

f

where

K

is

the

constant

indi-

10.24

x

1

0

°

i2

cated

and

R

p

is

the

external

control

resistance.

Model

6826A:

R

c

Ay

at

low

range

(XI):-——

10.24

x

10

3

10

R

f

Ay

at

high

range

(X10):-

10.24

x

10

3

Model

6827A:

.

2R

Ay

at

low

range

(XI):

.-

—

10.24

x

I

O

3

,

^

20

R

f

Ay

at

high

range

(XI0):

.

——-

10.24

x

10

3

Table

1-1.

Specifications,

Mode!

s6826A

and

6827A

{Continued)

Variable

Accuracy:

Accuracy

in

high

range

at

100Hz

using

an

external

control

resistance

(Rp)

at

output

voltage

(Vo)-

%

Rp

is

the

accuracy

of

the

control

resistance

Rp.

Model

6826A:

(.05%

+

%R

F

)

V

0

+

5mV

Model

6827A:

(.05%

+

%Rp)

Vo

+

10mV

Remote

Voltage

Control

Coefficient:

Fixed

gain

amplifier

mode,

voltage

coefficient:

Model

6826A:

Voltage

(XI

Range):

1

volt/volt

±

.1%

Voltage

(X10

Range):

10

volts/volt

±

.1%

Model

6827A:

Voltage

(XI

Range):

2

volts/volt

±

.1%

Voltage

(X10

Range):

20

volts/volt

±

.1%

Constant

Current,

voltage

coefficient

(the

following

applies

to

variable

gain

amplifier,

fixed

gain

amplifier,

and

power

supply

modes

of

operation):

Models

6826A

and

6827A:

1

ampere/volt

±

.5%

1-14

OPTIONS

1-15

Options

are

customer-requested

factory

modifica¬

tions

of

a

standard

instrument.

The

option

described

below

applies

to

Models

6826A

and

6827A.

Option

No

.

Description

007

Ten-turn

Output

Voltage

Control:

Replaces

standard

single-turn

voltage

control

to

allow

greater

resolution

in

setting

the

output

volt¬

age

ir

gain

of

the

BPS/A.

Shunt

resistor

A1

R53

as

well

as

standard

VOLTAGE

con¬

trol

(HP

Part

No.

2100-3272)

A5R2

must

be

removed

when

the

ten-turn

output

volt¬

age

control

(HP

Part

No.

2100-1867)

is

in¬

stalled

in

the

A5R2

location.

1-16

ACCESSORIES

1-17

The

accessories

listed

in

the

following

chart,

may

be

ordered

with

the

instrument

or

separately

from

your

local

Hewlett-Packard

sales

office

(refer

to

list

at

rear

of

manual

for

addresses).

HP

Part

No.

5060-8762

5060-8760

11057A

1052A

Dual

Rack

Adapter:

Kit

for

rack

mounting

one

or

two

supplies

in

standard

19-inch

rack.

Blank

Panel:

Filler

panel

to

block

unused

half

of

rack

when

mounting

only

one

supply.

Carrying

handle

easily

attached

for

portabil¬

ity

and

handling

convenience.

Combining

Case

for

mounting

one

or

two

units

in

standard

19-inch

rack.

5060-0789

Cooling

kit

for

above

combining

case,

115

Vac,

50-60Hz.

5060-0796

Cooling

kit

for

above

combining

case,

230

Vac,

50-60Hz.

1-18

INSTRUMENT

IDENTIFICATION

1-19

Hewlett-Packard

power

supplies

are

identified

by

a

three-part

serial

number.

The

first

part

is

the

power

supply

model

number.

The

second

part

is

the

serial

number

prefix,

consisting

of

a

number-letter

combination

denoting

the

date

of

a

significant,

design

change

and

the

country

of

manufac¬

ture.

The

first

two

digits

indicate

the

year

(12

=

1972,

13

=

1973,

20

-

1980,

etc);

the

second

two

digits

indicate

the

week

(01

through

52);

and

the

letter

"A",

"G",

"J",

or

"U"

designates

the

U.S.A.,

West

Germany,

Japan,

or

the

United

Kingdom,

respectively,

as

the

country

of

manufacture.

The

third

part

is

the

power

supply

serial

number;

a

different

5-

digit

sequential

number

is

assigned

to

each

power

supply,

starting

with

00101.

1-20

If

the

serial

number

prefix

on

your

unit

does

not

agree

with

the

prefix

on

the

title

page

of

this

manual,

change

sheets

supplied

with

the

manual

or

manual

backdating

changes

in

Appendix

A

define

the

differences

between

your

instrument

and

the

instrument

described

by

this

manual.

1-21

ORDERING

ADDITIONAL

MANUALS

1-22

One

manual

is

shipped

with

each

instrument.

Add¬

itional

manuals

may

be

purchased

from

your

local

Hewlett-

Packard

field

office

(see

list

at

rear

of

this

manual

for

add¬

resses).

Specify

the

model

number,

serial

number

prefix,

and

HP

part

number

shown

on

the

title

page.

SECTION

II

INSTALLATION

2-1

INITIAL

INSPECTION

2-2

Before

shipment,

this

instrument

was

inspected

and

found

to

be

free

of

mechanical

and

electrical

defects.

As

soon

as

the

instrument

is

received,

proceed

as

instructed

in

the

following

paragraphs.

2-3

MECHANICAL

CHECK

2-4

If

external

damage

to

the

shipping

carton

is

evident,

ask

the

carrier's

agent

to

be

present

when

the

instrument

is

unpacked.

Check

the

instrument

for

external

damage

such

as

broken

controls

or

connectors,

and

dents

or

scratches

on

the

panel

surfaces,

if

the

instrument

is

damaged,

file

a

claim

with

the

carrier's

agent

and

notify

your

local

Hewlett-Packard

Sales

and

Service

Office

as

soon

as

possible

(see

list

at

rear

of

this

manual

for

addresses).

2-5

ELECTRICAL

CHECK

2-6

Check

the

electrical

performance

of

the

instrument

as

soon

as

possible

after

receipt.

Section

V

of

this

manual

contains

performance

check

procedures

which

will

verify

in¬

strument

operation

within

the

specifications

stated

in

Table

1-

1

.

This

check

is

also

suitable

for

incoming

quality

control

inspection.

Refer

to

the

inside

front

cover

of

the

manual

for

the

Certification

and

Warranty

statements.

2-

7

REPACKAGING

FOR

SHIPMENT

2-8

To

insure

safe

shipment

of

the

instrument,

it

is

recommended

that

the

package

designed

for

the

instrument

be

used.

The

original

packaging

material

is

reusable.

If

it

is

not

available,

contact

your

local

Hewlett-Packard

field

office

to

obtain

the

materials.

This

office

will

also

furnish

the

add¬

ress

of

the

nearest

service

office

to

which

the

instrument

can

be

shipped.

Be

sure

to

attach

a

tag

to

the

instrument

speci¬

fying

the

owner,

model

number,

full

serial

number,

and

ser¬

vice

required,

or

a

brief

description

of

the

trouble.

2-9

INSTALLATION

DATA

2-10

The

instrument

is

shipped

ready

for

bench

opera¬

tion.

It

is

necessary

only

to

connect

the

instrument

to

a

source

of

power

and

it

is

ready

for

operation.

2-11

LOCATION

2-12

This

instrument

is

convection

cooled.

Sufficient

space

should

be

allotted

so

that

a

free

flow

of

cooling

air

can

reach

the

top

and

rear

of

the

instrument

when

it

is

in

operation.

It

should

be

used

in

an

area

where

the

ambient

temperature

remains

between

0°C

and

+55°C.

2-13

OUTLINE

DIAGRAM

2-14

Figure

2-1

illustrates

the

outline

shape

and

dimen¬

sions

of

Models

6826A

and

6827A.

2-15

RACK

MOUNTING

2-16

The

Mode!

6826A

and

6827A

BPS/A's

may

be

rack

mounted

using

either

the

dual

rack

adapter

kit

or

the

com¬

bining

case

(with

appropriate

cooling

kit)

described

in

Para¬

graph

1-16.

The

necessary

installation

instructions

are

pro¬

vided

with

the

accessories.

Refer

to

Paragraph

5-91

before

proceeding

with

the

rack

mounting

installation

instructions.

2-1

2-17

INPUT

POWER

REQUIREMENTS

2-18

Models

6826A

and

6827A

may

be

operated

contin¬

uously

from

either

a

nominal

120

volt

or

240

volt,

48-63

Hz

power

source.

A

two-position

selector

switch

{

|

)

loca¬

ted

within

the

a-c

power

module

on

the

rear

panel

selects

the

power

source.

Before

connecting

the

instrument

to

the

power

source,

check

that

the

selector

switch

setting

matches

the

nominal

line

voltage

of

the

source.

If

required,

move

the

switch

to

the

other

position.

Note

that

the

power

cable

must

be

removed,

the

plastic

door

on

the

power

module

must

be

moved

aside,

the

fuse

extractor

must

be

pulled

out¬

ward

and

the

fuse

must

be

removed

in

order

to

gain

access

to

the

selector

switch.

2-19

When

the

instrument

leaves

the

factory,

the

proper

fuse

is

installed

for

115

volt

operation.

An

envelope

con¬

taining

a

fuse

for

230

volt

operation

is

attached

to

the

instru¬

ment.

Make

sure

that

the

correct

fuse

is

installed

if

the

position

of

the

slide

switch

is

changed

(2A

for

115

volt

op¬

eration,

and

1A

for

230

volt

operation).

2-20

POWER

CABLE

2-21

To

protect

operating

personnel,

the

National

Elec¬

trical

Manufacturers'

Association

(NEMA)

recommends

that

the

instrument

panel

and

cabinet

be

grounded.

This

instru¬

ment

is

equipped

with

a

three

conductor

power

cable.

The

third

conductor

is

the

ground

conductor

and

when

the

cable

is

plugged

into

an

appropriate

receptacle,

the

instrument

is

grounded.

The

offset

on

the

power

cable's

three-prong

connector

is

the

ground

connection.

2-22

To

preserve

the

protection

feature

when

operating

the

instrument

from

a

two-contact

outlet,

use

a

three-prong

to

two-prong

adapter

and

connect

the

green

lead

on

the

adapter

to

ground.

2-2

SECTION

ill

DERATING

INSTRUCTIONS

Figure

3-1.

Bipolar

Power

Supply/Amplifier,

Models

6826A

and

6827A,

Rear

View

3-1

INTRODUCTION

3-2

This

section

describes

the

operating

controls

and

indicators,

the

turn-on

checkout

sequence,

and

operating

modes

of

Bipolar

Power

Supply/Amplifier

(BPS/A)

models

6826A

and

6827A.

Local

and

remote

programming

opera¬

tions

are

also

described.

3-3

REAR

TERMINALS

AND

AC

INPUT

3-4

The

Bipolar

Power

Supply/Amplifier

(BPS/A)

is

shipped

with

the

rear

terminals

strapped

for

local

program¬

ming

(using

front

pane!

controls)

as

shown

in

Figure

3-1.

Remote

programming

strapping

requirements

are

described

in

subsequent

paragraphs.

The

power

module

contains

fuse

FI

(2A

for

115Vac

or

1A

for

230Vac)

and

a

slide

switch

for

connecting

115Vac

or

230Vac

input

power

to

the

instru¬

ment.

To

turn

on

the

BPS/A,

set

the

LINE

switch

(item

(T)

,

Figure

3-2)

to

ON.

The

LINE

ON

indicator

(2)

should

light.

Fuse

FI

protects

the

main

power

supply.

At

initial

turn-on,

an

interna!

circuit

protects

any

loads

con¬

nected

to

the

BPS/A

from

turn-on

transients

by

shorting

the

output

terminals

and

disabling

the

BPS/A's

power

out¬

put

circuits.

This

circuit

operates

similarly

at

turn-off

to

protect

any

loads

from

turn-off

transients.

3-5

OPERATING

CONTROLS

AND

INDICATORS

3-6

MODE

SWITCH

3-7

The

MODE

switch

@

allows

the

BPS/A

to

oper

ate

as

a

power

supply,

variable

gain

amplifier,

or

a

fixed

gain

amplifier.

In

the

power

supply

operation,

the

BPS/A

pro¬

vides

a

variable

bipolar

dc

output

voltage

dependent

upon

the

RANGE

switch

(4)

and

VOLTAGE

control

(§)

settings.

The

dc

output

voltage

ranges

are

as

follows:

3-1

Figure

3-2.

Operating

Controls

and

Indicators

and

amplifies

an

external

input

signal

applied

to

the

HI

and

LO

IN

terminals.

For

fixed

gain

amplifier

operation,

the

6826A

has

a

frequency

response

from

DC

to

40kHz

and

the

6827A

has

a

frequency

response

from

DC

to

30kHz.

The

fixed

voltage

gain

provided

in

the

high

or

low

output

range

is

as

follows:

3-8

In

variable

gain

amplifier

operation,

the

BPS/A

can

amplify

or

attenuate

an

external

input

signal

(dc

to

15kHz)

applied

to

the

Hi

and

LO

IN

terminals.

The

gain

is

variable

from

0

to

a

maximum

depending

upon

the

RANGE

switch

(

4

)

and

VOLTAGE

control

(

5

)

settings.

The

variable

gain

ranges

are

as

follows:

3-10

RANGE

SWITCH

3-11

The

RANGE

switch

(4)

allows

selection

of

the

high

(X10)

or

tow

(XI)

output

ranges

for

power

supply,

variable

gain

amplifier,

or

fixed

gain

amplifier

operation.

The

REMOTE

position

allows

the

high

or

low

range

to

be

externally

selected

via

the

rear

terminal

strip

(see

Paragraph

3-9

In

fixed

gain

amplifier

operation,

the

BPS/A

inverts

3-45).

LOW

RANGE

6826A

0-20

0-2

6827A

0-40

0-4

1

6826A

X10

XI

6827A

X20

X2

MODEL

DC

OUTPUT

VOLTAGE

HIGH

RANGE

LOW

RANGE

6826A

6827A

-50V

to

+50V

-100V

to

t-IOOV

—5V

to

+5V

-10V

to

+

10V

3-2

3-12

VOLTAGE

CONTROL

3-13

The

VOLTAGE

control

®

controls

the

output

level

(power

supply

operation)

or

gain

(variable

gain

ampli¬

fier

operation)

of

the

BPS/A.

In

powensupply

operation,

the

VOLTAGE

control

varies

the

output

voltage

from

a

maximum

negative

value

(full

counterclockwise)

through

zero

(midposition}

to

a

maximum

positive

value

(full

clock¬

wise).

In

variable

gain

amplifier

operation,

the

gainls

vari¬

able

from

zero

to

the

maximum

gain

as

the

VOLTAGE

con¬

trol

is

varied

from

full

counterclockwise

to

full

clockwise.

In

fixed

gain

amplifier

operation,

the

VOLTAGE

control

does

not

control

circuit

operation.

3-14

CURRENT

CONTROL

3-15

The

CURRENT

control

(6)

sets

the

constant

current

output

of

the

BPS/A.

This

control

is

operable

in

all

three

modes

of

operation

(power

supply,

variable

gain

ampli¬

fier,

and

fixed

gain

amplifier)

and

controls

the

output

cur¬

rent

from

0

to

the

maximum

rated

output

(1.0A

for

the

6826A

and

0.5A

for

the

6827A).

When

the

instrument

switches

from

constant

voltage

to

constant

current

operation,

the

CURRENT

MODE

indicator

©

tights.

Selection

of

constant

voltage

or

constant

current

operation

is

described

in

Paragraphs

3-27

and

3-28,

3-16

VOLTAGE

METERING

3-17

The

VOLTAGE

METER

switch

(8)

permits

mon¬

itoring

the

DC

or

AC

output

voltage

on

voltmeter

®

.

The

shaded

area

on

the

voltmeter

face

indicates

the

amount

of

output

voltage

that

is

available

in

excess

of

the

norma!

rated

output.

The

voltmeter

upper

scale

reads

the

bipolar

DC

voltage

from

a

maximum

negative

value

through

OV

to

a

maximum

positive

value,

DC

accuracy

is

±3%

of

full

scale.

The

lower

scale

reads

the

RMS

output

voltage

from

0

to

a

maximum

level.

AC

accuracy

is

±5%

of

full

scale.

The

volt¬

meter

ranges

selected

by

the

VOLTAGE

METER

switch

are

as

follows:

MODEL

VOLTMETER

RANGES

DC

AC

(RMS)

6826A

6827A

0

to

±6V,0

to

±60V

Oto

±12V,0to±

120V

0-4V

(uncai),

0-40V

0-8V

(uncai),

0-80V

3-18

CURRENT

METERING

3-19

The

CURRENT

METER

switch

@

permits

monitoring

the

DC

or

AC

output

current

on

ammeter

(H)

The

shaded

area

on

the

ammeter

face

indicates

the

amount

of

output

current

that

is

available

in

excess

of

the

normal

rated

output.

The

ammeter

upper

scale

reads

the

bipolar

DC

current

from

a

maximum

negative

value

through

OA

to

a

maximum

positive

value.

DC

accuracy

is

±3%

of

full

scale.

The

lower

scale

reads

the

RMS

output

current

from

0

to

a

maximum

level.

AC

accuracy

is

±5%

of

full

scale.

The

am¬

meter

ranges

selected

by

the

CURRENT

METER

switch

are

as

follows:

MODEL

AMMETER

RANGES

DC

AC

(RMS)

6826A

6827A

0

to

±0.12A,0

to

±1.2A

0

to

±Q.06A,0

to

±0.6A

0

to

0.08A,0

to

0.8A

0

to

0.04A,0

to

0.4A

3-20

TURN-ON

CHECKOUT

PROCEDURES

-CAUTION--—

Rear

terminal

strip

cover

must

be

in

place

when

Instrument

is

in

use.

Also,

the

Local/Auto

switch,

located

inside

the

unit

on

board

A2

(see

Figure

3-9),

is

in

the

Local

position

(toward

rear

of

unit)

as

shipped

from

the

factory.

The

Local

positions

is

used

for

normal

operations.

The

Auto

position

is

used

only

for

auto-series

and

auto-parallel

operations

(see

Paragraphs

3-57

through

3-61).

If

the

switch

is

placed

in

the

Auto

position

for

normal

operations,

the

BPS/A

output

voltage

could

latch

up

(maximum

positive

or

negative

output).

3-21

The

following

turn-on

and

checkout

procedures

are

performed

utilizing

the

front

panel

controls

(Figure

3-2)

and

the

normal

rear

terminal

strapping

connections

as

re¬

ceived

from

the

factory.

POWER

SUPPLY

CHECKOUT

PROCEDURE

a.

Set

front

panel

controls

as

follows:

MODE

switch

©

—

POWER

SUPPLY

RANGE

switch

©

-

XI

VOLTAGE

control

©

-midposition

CURRENT

control

(6)

—

full

clockwise

VOLTAGE

METER

switch

@

-

low

range

DC

CURRENT

METER

switch

@

-high

range

DC

b.

Set

LINE

switch

©

to

ON

and

observe

that

LINE

ON

indicator

©

lights.

c.

Adjust

VOLTAGE

control

©

from

full

counter¬

clockwise

{-)

to

full

clockwise

(+}

range

through

0V

and

note

that

maximum

output

is

attained

as

indicated

on

meter

®

•

d.

Set

VOLTAGE-METER

switch

©

to

high

range

DC

and

RANGE

switch

@

to

X10

position.

e.

Adjust

VOLTAGE

control

©

clockwise

and

counterclockwise

through

entire

bipolar

output

voltage

3-3

range

through

0

and

note

that

maximum

output

is

attained

as

indicated

on

meter

©

Adjust

output

voltage

to

+50V.

f.

To

checkout

the

constant

current

circuit,

first

turn

off

BPS/A.

Short

circuit

the

front

panel

terminals

{HI

OUT

to

LO

OUT).

g.

Turn

on

supply

and

observe

that

CURRENT

MODE

indicator

©

lights

and

meter

(9)

indicates

0

volts.

h.

Adjust

CUR

RENT

control

©

from

full

cw

to

full

ccw

and

note

that

minimum

current

is

attained

as

indi¬

cated

on

meter

(fl)

i.

Turn

off

supply

and

remove

short

from

output

term¬

inals.

j.

Turn

on

supply

and

adjust

VOLTAGE

CONTROL

(§)

for

an

output

of

—50V.

k.

Turn

off

supply

and

reconnect

short

across

the

HI

and

LO

OUT

terminals.

l.

Turn

on

supply

and

note

that

CURRENT

MODE

in¬

dicator

(?)

lights

and

meter

©

indicates

0

volts.

m.

Adjust

CURRENT

control

(6)

from

full

cw

to

full

ccw

and

note

that

minimum

current

is

attained

as

indi¬

cated

on

meter

(Pi)

n.

Turn

off

BPS/A

and

remove

short

from

output

term¬

inals.

VARIABLE

GAIN

AMPLIFIER

CHECKOUT

PROCEDURE

o.

Set

front

panel

controls

as

follows:

MODE

switch©

-VAR

GAIN

AMP

RANGE

switch

@

-XI

VOLTAGE

control

©

—

midposition

CURRENT

control

©

—

full

clockwise

VOLTAGE

METER

switch

©

-

low

range

AC

CURRENT

METER

switch

©

-

high

range

AC

p.

Connect

a

1.75V

rms,

100Hz

input

signal

to

the

front

panel

input

terminals

(HI

and

LO

IN).

q.

Turn

on

supply

and

adjust

VOLTAGE

control

©

through

entire

RMS

range

and

note

that

maximum

voltage

is

attained

as

indicated

on

meter

©)

.

r.

Set

VOLTAGE

METER

switch

©

to

high

range

AC,

RANGE

switch

©

to

X10,

and

adjust

VOLTAGE

control

©

through

entire

RMS

range

and

note

that

max¬

imum

voltage

is

attained

as

indicated

on

meter

©

FIXED

GAIN

AMPLIFIER

CHECKOUT

PROCEDURES

s.

Set

MODE

switch

©)

to

FXD

GAIN

AMP

posi¬

tion

and

increase

input

signal

to

3.5V

rms.

t.

Adjust

VOLTAGE

control

©)

through

entire

RMS

range

and

note

that

maximum

voltage

is

attained

as

indicated

on

meter

©)

3-22

OPERATING

MODES

—-CAUTION--——

3-23

The

position

of

the

front

panel

MODE

switch

de¬

termines

whether

the

instrument

will

be

used

as

a

power

supply

or

an

amplifier.

In

addition,

the

instrument

may

be

controlled

locally

using

the

front

panel

VOLTAGE

and

CURRENT

controls

or

remotely

via

terminals

on

the

rear

of

the

unit.

The

front

panel

output

terminals

(HI

and

LO

OUT)

and

input

terminals

(HI

and

LO

IN)

are

repeated

as

{+

and

—)

and

(A1

and

A2)

respectively

on

the

rear

termin¬

al

strip.

The

rear

terminal

strip

includes

sensing

(+S

and

—S)

terminals

and

other

terminals

for

remote

control

of

the

BPS/A

as

shown

in

Figure

3-3.

These

terminals

connect

to

various

control

points

within

the

instrument

and

allow

strapping

connections

to

be

made

which

enable

the

power

supply

or

amplifier

to

be

utilized

in

many

applications.

The

following

paragraphs

describe

the

procedures

for

utilizing

the

various

operational

capabilities

of

the

power

supply.

A

more

theoretical

description

concerning

the

operational

features

of

this

supply

is

contained

in

Application

Note

90

and

in

various

Tech.

Letters.

Copies

of

these

can

be

obtained

from

your

local

Hewlett-Packard

field

office.

SIGNAL

INPUT

TERMINALS

hfT'T

(LO)

i

(HI)

OUTPUT

—

TERMINALS

REMOTE

RANGE

CONTROI

CONSTANT

VOLTAGE

PROGRAMMING

(

+

)

CONSTANT

CURRENT

PROGRAMMING

r

.

1

.

—\

AS

AIO

All

.412

AI3

A14

0|0]0j0

CONSTANT

CURRENT

FLAG

OUTPUT

PROGRAM

INTERRUPT

(-)

CONSTANT

RELAY

CONTROL

I

CURRENT

PROGRAMMING

,.

J

.

'

r

.-

-

A

'

AI5

AI6'AI7'Al8

AI9

420

A2I

0

0|

0j0j

C")

/>

0

Figure

3-3.

Rear

Terminal

Strip

3-24

LOCAL

PROGRAMMING

3-25

The

BPS/A

is

shipped

with

its

rear

terminal

strap¬

ping

connections

arranged

for

constant

voltage/constant

current,

local

programming,

local

sensing,

single

unit

mode

of

operation.

This

strapping

pattern

is

illustrated

in

Figure

3-4.

Also,

the

Local/Auto

switch

on

board

A2

(see

Para¬

graph

3-54)

is

in

the

Local

position

when

the

instrument

is

shipped

from

the

factory.

This

switch

mu

s

t

be

in

the

Local

position

for

single

unit

mode

of

operation.

Rear

terminal

strip

cover

must

be

in

place

when

instrument

is

in

use.

3-26

The

operator

selects

either

power

supply,

variable

gain

amplifier,

or

fixed

gain

amplifier

operation

(MODE

3-4

switch)

and

also

selects

either

constant

voltage

or

a

constant

current

output

using

the

front

pane!

VOLTAGE

and

CUR¬

RENT

controls

(for

local

programming,

no

strapping

changes

are

required).

Constant

voltage

or

constant

current

opera¬

tion

are

selected

as

described

in

the

following

paragraphs.

(LOCAL

Programming)

3-27

Constant

Voltage.

To

select

a

constant

voltage

output,

proceed

as

follows;

a.

Remove

load

from

output

terminals;

turn-on

supply

and

adjust

VOLTAGE

control

for

desired

output

voltage.

b.

Short

output

terminals

and

adjust

CURRENT

con¬

trol

for

maximum

output

current

allowable

(current

limit)

as

determined

by

load

conditions

and

voltage

range

selected

in

step

(a).

If

a

load

change

takes

place

and

causes

the

out¬

put

current

to

exceed

this

setting,

the

power

supply

will

automatically

crossover

to

constant

current

mode

and

out¬

put

current

will

be

constant

at

the

level

set

by

the

CURRENT

control.

The

CURRENT

MODE

indicator

will

come

on

and

output

voltage

will

drop

proportionately

to

maintain

con¬

stant

current.

3-28

Constant

Current.

To

select

a

constant

current

output,

proceed

as

follows;

a.

Short

output

terminals

and

adjust

CURRENT

con¬

trol

for

desired

output

current.

b.

Open

output

terminals

and

adjust

VOLTAGE

con¬

trol

for

maximum

output

voltage

allowable

as

determined

by

load

conditions

and

current

selected

in

step

(a).

If

a

load

change

causes

the

voltage

to

rise,

the

power

supply

will

automatically

crossover

to

constant

voltage

at

the

voltage

setting

and

output

current

will

drop

proportionately,

3-29

OPERATION

OF

SUPPLY

BEYOND

RATED

OUTPUT

3-30

The

shaded

area

on

the

front

panel

meters

indicate

the

amount

of

output

voltage

and

current

that

is

available

in

excess

of

normal

rated

output.

Although,

the

BPS/A

can

be

operated

in

this

region

without

damage,

it

cannot

be

guaranteed

to

meet

all

of

its

performance

specifications.

3-31

REACTIVE

LOAD

CONSIDERATIONS

3-32

The

life

and

performance

of

the

instrument

can

be

preserved

if

the

following

simple

precaution

is

observed

when

driving

reactive

loads.

Always

set/program

the

VOLT¬

AGE

control

for

zero

output

before

removing

a

capacitive

load

or

interrupting

an

inductive

load.

3-33

CONNECTING

LOAD

3-34

Each

load

should

be

connected

to

the

power

sup¬

ply

output

terminals

(front

or

rear)

using

separate

pairs

of

connecting

wires.

This

will

minimize

mutual

coupling

ef¬

fects

between

loads

and

will

retain

full

advantage

of

the

low

output

impedance

of

the

power

supply.

Each

pair

of

connecting

wires

should

be

as

short

as

possible

and

twisted

or

shielded

to

reduce

noise

pickup.

(If

a

shielded

pair

is

used,

connect

the

shield

to

ground

at

the

power

supply

and

leave

the

other

end

unconnected.)

3-35

If

load

considerations

require

that

the

output

power

distribution

terminals

be

remotely

located

from

the

power

supply,

then

the

power

supply

output

terminals

should

be

connected

to

the

remote

distribution

terminals

via

a

pair

of

twisted

or

shielded

wires

and

each

load

should

be

separately

connected

to

the

remote

distribution

terminals.

For

this

case,

remote

sensing

should

be

used.

(Refer

to

Paragraph

3-39).

3-36

Always

use

two

leads

to

connect

the

load

to

the

supply,

regardless

of

where

the

setup

is

grounded.

This

will

eliminate

any

possibility

of

output

current

return

paths

through

the

power

source

ground.

The

supply

can

also

be

operated

up

to

300Vdc

above

ground

if

neither

output

ter¬

minal

is

grounded.

3-37

REMOTE

SENSING

3-38

Remote

sensing

is

used

to

maintain

good

regulation

at

the

load

and

reduce

the

degradation

of

regulation

which

would

occur

due

to

the

voltage

drop

in

the

leads

between

the

power

supply

and

the

load.

Remote

sensing

is

accom¬

plished

by

utilizing

the

strapping

pattern

shown

in

Figure

3-5.

The

power

supply

should

be

turned

off

before

chang¬

ing

strapping

patterns.

The

leads

from

the

sensing

(±S)

terminals

to

the

load

will

carry

much

less

current

than

the

load

leads

and

it

is

not

required

that

these

leads

be

as

heavy

as

the

load

leads.

However,

they

must

be

twisted

or

shielded

to

minimize

noise

pickup.

3-5

CAUTION

Observe

polarity

when

connecting

sense

leads

to

the

load.

3-39

For

reasonable

load

lead

lengths,

remote

sensing

limits

degradation

of

the

performance

of

the

supply.

How¬

ever,

if

the

load

is

located

a

considerable

distance

from

the

supply,

added

precautions

must

be

observed

to

obtain

satis¬

factory

operation.

Notice

that

the

voltage

drop

in

the

load

leads

subtracts

directly

from

the

available

output

voltage.

Because

of

this,

it

is

recommended

that

the

drop

in

each

load

lead

not

exceed

1.0

volt,

if

a

larger

drop

must

be

toler¬

ated,

please

consult

an

HP

Sales

Engineer.

NOTE

Due

to

the

voltage

drop

in

the

load

leads,

it

may

be

necessary

to

readjust

the

constant

current

crossover

limit

setting

in

the

remote

sensing

mode.

3-40

REMOTE

PROGRAMMING

---CAUTION--—

External

programming

resistors

must

be

connec¬

ted

to

the

appropriate

rear

terminals

before

power

is

applied

to

the

instrument

3-41

The

constant

voltage

and

constant

current

outputs

of

the

BPS/A

can

be

programmed

{controlled)

from

a

re¬

motely

located

device

such

as

HP

6940A

Multiprogrammer

or

HP

6941A

Multiprogrammer

Extenders.

Either

a

resis¬

tance

or

voltage

source

can

be

used

as

the

programming

de¬

vice.

The

wires

connecting

the

programming

terminals

on

the

rear

of

the

BPS/A

to

the

remote

programming

device

should

be

twisted

or

shielded

to

reduce

noise

pickup,

3-42

Resistance

Programming

Constant

Voltage.

A

programming

resistor

(Rpy),

connected

as

shown

in

Figure

3-6,

can

be

used

to

control

the

voltage

output

or

gain

pro¬

vided

that

the

MODE

switch

is

in

the

POWER

SUPPLY

or

the

VARIABLE

GAIN

AMP

position.

Resistance

program¬

ming

of

the

constant

voltage

output

is

not

applicable

in

the

FXD

GAIN

AMP

mode

of

operation.

The

VOLTAGE

con¬

trol

on

the

front

panel

is

disconnected

(disabled)

for

the

strapping

connections

shown

in

Figure

3-6.

To

maintain

the

stability

and

temperature

coefficient

of

the

instrument,

use

programming

resistors

that

have

stable

low

noise

and

low

temperature

characteristics

{less

than

20

ppm/°C.).

Also,

they

should

operate

at

less

than

1/30th

of

their

wattage

rat¬

ing

to

minimize

short

term

temperature

effects.

X

MUST

BE

ISOLATED

FROM

CONTROL

GROUND

Figure

3-6.

Remote

Resistance

Programming,

Constant

Voltage/Constant

Current

3-43

Power

Supply.

For

power

supply

operation,

the

bipolar

output

voltage

varies

linearly

from

a

maximum

neg¬

ative

value

through

zero

to

a

maximum

positive

value

accord

ing

to

the

value

of

the

programming

resistance

Rpv-

The

voltage

output

ranges

and

corresponding

values

of

Rpy

are

as

follows:

3-6

Rpv

VALUE

6826A

6827A

HIGH

RANGE

LOW

RANGE

HIGH

RANGE

LOW

RANGE

0

-51.2V

-5.12V

-102.4V

-10.24V

10.24KO

OV

20.48

KH

+51.2V

+5.12V

+

102.4V

+

10.24V

3-44

As

noted

above,

the

output

voltage

should

be

zero

volts

with

10.24K

connected

to

the

programming

terminals.

The

output

may

be

adjusted

to

zero

by

adjusting

the

V

ZERO

ADJ

potentiometer

as

described

in

Paragraph

5-104.

The

output

voltage

varies

from

the

maximum

negative

value

to

the

maximum

positive

value

through

0

at

a

rate

deter¬

mined

by

the

resistance

programming

coefficient

as

follows:

MODEL

*

PROGRAMMING

COEFFICIENT

HIGH

RANGE

LOW

RANGE

6826A

6827A

200

ohms/volt

±

.1%

100

ohms/volt

+

.1%

2000

ohms/volt

±

.1%

1000

ohms/volt

±

.1%

*

Precision

programming

resistors

(±0,05%)

must

be

used.

--CAUTION--

When

remote

control

programming

is

employed,

the

FLAG

(A

17)

and

REMOTE

RANGE

(A

11)

programming

connections

must

be

isolated

from

the

computer

ground.

3-45

The

switch

connected

between

the

A11

and

-S

terminals

allows

remote

selection

of

the

high

(X10)

or

low

(XI)

range.

Note

that

the

front

panel

RANGE

switch

must

be

in

the

REMOTE

position

in

order

to

utilize

the

remote

selection

feature.

The

remote

dc

control

voltage

connect¬

ions

between

terminals

A15

and

A16

activate

an

internal

relay.

When

the

control

voltage

is

applied,

the

internal

re¬

lay

is

energized

momentarily

disabling

the

input

driver

to

the

BPS/A

error

amplifier.

This

feature

is

used

to

prevent

transients

from

affecting

the

output

when

the

programming

input

is

changed.

Terminal

A17

provides

an

indication

to

the

external

programming

device

when

the

BPS/A

is

in

con¬

stant

current

operation.

3-46

Variable

Gain

Amplifier.

For

variable

gain

amplifier

operation,

an

external

input

signal

(dc

to

15kHz),

applied

to

terminals

A1

(HI

IN)

and

A2

(LO

IN),

is

amplified

or

atten¬

uated.

The

gain

is

variable

from

0

to

a

maximum

value

as

the

value

of

Rpy

varies

from

0

to

20.48K

ohms.

The

variable

gain

at

the

high

and

low

ranges

is

as

follows:

MODEL

VARIABLE

GAIN

HIGH

RANGE

LOW

RANGE

6826A

0-20

0-2

6827A

0-40

0-4

-CAUTION-

The

voltage

applied

to

the

input

terminals,

HI

IN

(A1)

and

LO

IN

(A2),

must

not

exceed

50

V

(maximum)

or

the

instrument

may

be

damaged.

3-47

Resistance

Programming,

Constant

Current.

Pro¬

gramming

resistors

(Rpc),

connected

as

shown

in

Figure

3

-6,

can

be

used

to

control

the

constant

current

output.

The

front

panel

CURRENT

control

is

disconnected

(disabled)

when

the

remote

Rpc

resistors

are

connected

as

indicated.

Resistance

programming

of

the

constant

current

output

can

be

accomplished

in

all

three

modes

of

operation

(power

supply,

variable

gain

amplifier,

and

fixed

gain

amplifier).

Individual

Rpc

resistors

control

positive

and

negative

con¬

stant

current

outputs

respectively.

The

positive

or

negative

output

current

is

variable

at

a

rate

determined

by

the

pro¬

gramming

coefficient

as

follows:

MODEL

OUTPUT

CURRENT

*

PROGRAMMING

COEFFICIENT

6826A

6827A

Oto

1.024A

Oto

.512A

10

ohms/mA

±

.1%

10

ohms/mA

±

.1%

*

Precision

programming

resistors

(±0.05%)

must

be

used.

--CAUTION-

A

load

must

be

maintained

at

all

times

during

constant

current

operation.

The

load

can

be

a

WOK

El

resistor

for

the

6826A

or

a

400K

LI

resistor

for

the

6827A.

3-48

Zero

output

current

for

zero

programming

resis¬

tance

can

be

assured

through

proper

adjustment

of

the

front

panel

+1

and

—I

ZERO

ADJ

potentiometers

(see

Paragraph

5-107).

3-49

Voltage

Programming,

Constant

Voltage.

Voltage

programming

of

the

output

voltage

can

be

accomplished

in

the

variable

gain

or

fixed

gain

amplifier

mode

of

operation.

Voitage

programming

is

not

applicable

in

the

power

supply

mode.

3-7

Figure

3-7.

Remote

Voltage

Programming,

Constant

Voltage

Figure

3-7

shows

a

variable

dc

level

(programming

voltage)

applied

to

the

Hi

(A1)

and

LO

(A2)

input

terminals.

Since

the

BPS/A

provides

an

inverted

output

in

the

fixed

gain

amplifier

mode,

a

positive

input

(A1

positive,

A2

negative)

results

in

a

negative

output

and

a

negative

input

(A1

nega¬

tive,

A2

positive)

results

in

a

positive

output.

The

front

panel

or

remote

programming

voltage

controls

are

not

appli

cable

in

this

mode.

The

programming

coefficient

in

the

fixed

gain

amplifier

mode

is

as

follows:

MAXIMUM

OUTPUT

PROGRAMMING

COEFFICIENT

IVIUUcL

HIGH

RANGE

LOW

RANGE

HIGH

RANGE

LOW

RANGE

6826A

±50V

*

+5V

10

volts/

volt

1

volt/

volt

6827A

+

100V

+

10V

20

volts/

volt

2

volts/

volt

3-50

Variable

Gain

Amplifier.

AC

signals

or

a

dc

level

(positive

or

negative)

can

be

amplified

or

attenuated

in

the

variable

gain

amplifier

mode.

Figure

3-7

shows

a

variable

dc

levei

(programming

voltage)

applied

to

the

input

termin¬

als

A1

(HI

IN)

and

A2

(LO

IN).

Since

the

BPS/A

is

non¬

inverting

in

the

variable

gain

amplifier

mode,

a

positive

input

(A1

positive,

A2

negative)

results

in

a

positive

output

and

a

negative

input

(A1

negative,

A2

positive)

results

in

a

nega¬

tive

output.

The

other

connections

on

Figure

3-7

are

shown

for

local

control

using

front

pane!

controls,

however,

remote

control

using

external

controls

may

also

be

employed.

The

front

panel

or

remote

voltage

controls

can

be

used

to

atten¬

uate

or

amplify

the

input

as

required.

With

the

front

panel

VOLTAGE

control

or

remote

programming

resistor

set

for

maximum

output,

the

programming

coefficient

is

as

follows:

MODEL

MAXIMUM

OUTPUT

^PROGRAMMING

COEFFICIENT

HIGH

RANGE

LOW

RANGE

HIGH

RANGE

LOW

RANGE

6826A

±50V

±5V

20

volts/

volt

2

volts/

volt

6827A

±100V

±10V

40

volts/

volt

4

volts/

volt

"With

front

panel

VOLTAGE

control

or

remote

program¬

ming

resistor

set

for

maximum

rated

output.

A!

A2

4-

-S

-

+S

+

010

0

§

[0

0

a

A8

A9

AI0

All

AIZ

y

vVv—’

R

l

AI3

A14

9

SL

0

I®

s

2

AI5

AI6

AI7

AI8

AI9

A20A21

0

4

0

M

P

-j&Z

X-

THESE

SUPPLIES

MUST

BE

ISOLATED

FROM

POWER

GROUND

Figure

3-8.

Remote

Voltage

Programming,

Constant

Current

3-52

Voltage

Programming,

Constant

Current.

Voltage

3-51

Fixed

Gain

Amplifier.

AC

signals

up

to

40kHz

programming

of

the

output

current

can

be

accomplished

in

(6826A)

or

30kHz

(6827A)

or

a

dc

level

(positive

or

nega-

all

three

operating

modes

(power

supply,

variable

gain

am-

tive)

can

be

amplified

in

the

fixed

gain

amplifier

mode.

plifier,

and

fixed

gain

amplifier).

Positive

and

negative

dc

3-8

A2

BOARD

LOCAL/AUTO

SWITCH

AUTO

POSITION

««

-

»

LOCAL

POSITION

(TOWARD

FRONT)

(TOWARD

REAR)

FRONT

OF

UNIT

Figure

3-9.

Locai/Auto

Switch

programming

voltages

are

connected

to

terminals

A14

and

A21

respectively

as

shown

in

Figure

3-8.

The

positive

or

negative

output

current

will

vary

linearly

with

changes

in

the

programming

voltages.

The

output

current

varies

at

a

rate

determined

by

the

programming

coefficient.

For

mod¬

els

6826A

and

6827A,

the

programming

coefficient

is

1

amp/

1

volt.

The

maximum

rated

output

current

for

the

6826A

is

1A,

therefore,

the

maximum

programming

voltage

for

6826A

is

1

volt.

The

maximum

rated

output

current

for

the

6827A

is

0.5A,

therefore,

the

maximum

programming

voltage

for

6827A

is

0.5V.

3-53

SERIES

AMD

PARALLEL

CONNECTIONS

3-54

The

following

paragraphs

describe

the

connections

required

for

combining

BPS/A's

for

series

and

parallel

oper¬

ations.

These

connections

are

employed

whenever

it

is

re¬

quired

to

extend

the

voltage/gain

or

current

capability

be¬

yond

one

supply.

For

series

operation,

the

total

output

voltage/gain

is

the

sum

of

the

voltages/gains

of

the

individ¬

ual

supplies.

For

parallel

operation,

the

total

output

current

is

the

sum

of

the

output

current

from

the

individual

supplies.

For

series

or

parallel

operation,

the

BPS/A's

must

be

opera¬

ted

in

the

same

mode

(power

supply,

variable

gain

amplifier,

or

fixed

gain

amplifier).

Also,

each

supply

must

have

its

Auto/Local

switch

A2S1

(see

Figure

3-9)

in

the

Local

posi¬

tion

(pushed

toward

the

rear

of

the

instrument).

Note

that

the

external

signal

applied

to

the

A1

and

A2

terminals

is

in¬

ternally

disconnected

when

the

BPS/A's

are

in

the

power

supply

mode.

3-55

Series

Connections.

Two

or

more

supplies

may

be

connected

in

series

to

obtain

a

higher

voltage/gain

than

is

available

from

a

single

supply,

Figure

3-10

illustrates

the

series

connections

for

three

supplies.

Each

of

the

supplies

must

be

adjusted

in

order

to

obtain

the

desired

output/

voltage

gain.

3-56

Parallel

Connections.

Parallel

operation

of

BPS/A

is

possible

because

of

the

constant

voltage/constant

current

crossover

feature.

Two

or

more

power

supplies

can

be

con¬

nected

in

parallel

to

obtain

a

total

output

current

greater

than

that

available

from

one

power

supply.

The

total

output

current

is

the

sum

of

the

output

currents

of

the

individual

power

supplies.

The

load

must

be

selected

so

that

the

current

limit

of

one

supply

is

exceeded

allowing

it

to

operate

in

the

constant

current

mode.

The

output

CURRENT

controls

of

each

power

supply

can

be

separately

set.

The

output

voltage

controls

of

one

power

supply

should

be

set

to

the

desired

output

voltage;

the

other

power

supply

should

be

set

for

a

3-9

that

fraction

of

its

total

rated

output

current

which

is

necess¬

ary

to

fulfill

the

total

current

demand.

Figure

3-11

illustrates

the

parallel

connections

for

three

units.

ALL

THREE

UNITS

MUST

BE

OPERATED

IN

THE

SAME

MODE

2

.

UNITS

2

A

NO

3

MUST

8E

FLOATED

(NOT

CONNECTED

TO

CHASSIS

i

Figure

3-10.

Series

Connections

L

AI5

AI6

Ai7

AI8

AI9

A20

A2!

NOTES:

1.

ALL

THREE

UNITS

MUST

BE

OPERATED

IN

THE

SAME

MODE

2.

UNITS

2

AND

3

MUST

8E

FLOATED

(NOT

CONNECTED

TO

CHASSIS

i-3

Figure

3-11,

Parallel

Connections

slightly

larger

output

voltage.

The

supply

set

to

the

lower

output

voltage

will

act

as

a

constant

voltage

source;

the

supply

set

to

the

higher

output

will

act

as

a

constant

current

source,

dropping

its

output

voltage

until

it

equals

that

of

the

other

supply.

The

constant

voltage

source

will

deliver

only

3-57

AUTO-SERIES

AMD

AUTO-PARALLEL

CONNECTIONS

3-58

The

following

paragraphs

describe

the

connections

required

for

combining

BPS/A's

in

auto-series

and

auto

3-10

parallel.

These

connections

are

employed

whenever

it

is

re¬

quired

to

extend

the

voltage/gain

or

current

capability

be¬

yond

one

supply.

For

auto-series

operation,

the

output

volt¬

age

of

each

slave

supply

varies

in

accordance

with

that

of

the

master

supply.

For

auto-paraliel

operation,

complete

control

of

the

output

current

from

one

master

is

allowed.

Diagrams

are

included

for

the

strapping

connections

re¬

quired

between

master

and

slaves

for

both

auto-series

and

auto-parallel

operations.

In

either

case,

the

master

must

be

in

the

power

supply

or

variable

gain

amplifier

mode

and

the

slaves

must

be

in

the

fixed

gain

amplifier

mode.

Also,

for

auto-series

or

parallel

operation,

the

master

supply's

Local/

Auto

switch

A2S1

{see

Figure

3-9)

must

be

in

the

Local

pos¬

ition

and

each

slave

supply

must

have

its

Local/Auto

switch

in

the

Auto

position.

The

diagrams

show

the

master

strapped

for

local

programming

and

with

an

external

signal

applied

to

the

amplifier

input

terminals.

However,

the

same

auto-series

or

auto-parallel

connections

could

be

used

with

the

master

strapped

for

remote

programming.

Also,

with

the

master

supply

in

the

power

supply

mode,

the

external

signal

applied

to

the

A1

and

A2

terminals

is

internally

disconnected.

3-59

Auto-Series

Operation.

Two

or

more

BPS/A's

can

be

connected

in

an

auto-series

arrangement

to

obtain

a

high¬

er

output

voltage

than

that

available

from

a

single

supply.

Figure

3-12

illustrates

the

auto-series

connections

for

three

supplies.

When

this

arrangement

is

used,

the

output

voltage

of

each

slave

supply

varies

in

accordance

with

that

of

the

master

supply;

thus,

the

total

output

voltage

of

the

combin¬

ation

is

determined

by

the

master

supply's

front

panel

VOLTAGE

control

(or

remote

programming

input).

The

front

panel

CURRENT

controls

(or

remote

programming

inputs)

of

all

three

units

are

operative

and

the

current

limit

is

equal

to

the

lowest

setting.

The

slave

units

must

be

floated

off

ground.

Instruments

can

be

operated

floating

up

to

300

volts

off

ground

whether

operated

singlely

or

in

series.

This

limits

model

6826A

(±50V

@

1.0A)vto

six

units

in

series

and

model

6827A

(±100V

@

0.5A)

to

three

units

in

series.

3-60

For

instantaneous

equal

voltage

sharing,

resistors

R-j,

R2,

or

R3

must

be

equal.

Since

any

variation

in

R2,

or

R3

will

result

in

a

change

in

the

voltage

divider

ratio

and

hence

the

output

of

the

slave

supply,

it

is

important

that

these

resistors

be

stable,

low

temperature

coefficient

(20

ppm/°C

or

better).

Also,

they

should

have

power

rating

of

at

least

10X,

their

actual

power

dissipation.

The

resis¬

tors

should

be

selected

at

the

normal

operating

voltage

levels

so

that

the

current

through

them

is

about

1

to

2mA.

3-61

Auto-Parallel

Operation.

Two

or

more

BPS/A's

can

be

connected

in

auto-parallel

arrangement

to

obtain

an

output

current

greater

than

that

available

from

a

single

sup¬

ply.

Figure

3-13

illustrates

the

auto-parallel

connections

for

three

supplies

to

allow

increased

output

current

in

con¬

stant

voltage

operation.

When

this

arrangement

is

used,

current

sharing

under

all

load

conditions

is

permitted

under

control

(front

panel

CURRENT

control

or

remote

program¬

ming)

of

the

master

supply.

Because

the

CURRENT

con¬

trols

(or

remote

programming)

of

each

slave

are

operative,

they

should

be

set

to

a

maximum

to

prevent

the

slave

re¬

verting

to

constant

current

operation;

this

could

occur

if

the

master

output

current

setting

exceeded

the

slave’s.

For

equal

current

sharing,

the

leads

from

Rfy]

to

the

load

and

to

the

(—)

terminals

should

be

approximately

equal

in

length.

To

maintain

instrument

accuracy

and

stability,

R|yj

should

be

a

stable,

low

temperature

coefficient

resistor

of

sufficient

rating

to

prevent

any

appreciable

self-heating

(typically

1£2,

8W,

±20

ppm/°C,

±1%).

3-11

HP 6826A Service manual

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