Keithley 220 Service manual

Model 220 Programmable Current Source

Instruction Manual-

01982, Keithley Instruments, Inc.

Cleveland, Ohio, U.S.A.

Eighth Printing, August 2000

Document Number: 220-901-01 Rev. H

Manual Print History

The print history shown below lists the printing dates of all Revisions and Addenda created for this manual. The Revision Level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are released between Revisions, contain important change information that the user should incorporate immediately into the manual. Addenda are numbered sequentially. When a new Revision is created, all Addenda associated with the previous Revision of the manual are incorporated into the new Revision of the manual. Each new Revision includes B revised copy of this print history page.

Revision G (Document Number 220-901-01) Revision H (Document Number 220-901-01)

.............................................................. 1992

.................................................. August2000

Safety Precautions

The following safety precautions should be observed before using this product and any associated instrumentation. Although some instruments and accessories would normally be used with nonhazardous voltages, there are situations where hazardous conditions may be present.

This product is intended for use by qualified personnel who mcog-

nize shock hazards and are familiar with the safety precautions mquired to avoid possible injury. Read the operating information

carefully before using the product. The types of product users are: Responsible body is the individual or group responsible for the use

and maintenance of equipment. for ensuring that the equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained.

Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the instnmat. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform mutine procedures on the product to keep it operating, for example, setting the line voltage or replacing consumable materials. Maintenance procedures are described in the manual. The procedures explicitly state if the operator may perform them. Othenvise, they should be performed only by service p~~SONE1.

Service personnel are trained to work on live circuits, and perform safe installations and repairs of pmducts. Only properly trained service personnel may perform installation and service procedures.

Users of this product must be protected from electric shock at all times. The responsible body must ensure that users are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential human contact. Product users in these circumstances must be trained to protect themselves from the risk of electric shock. If the circuit is capable of operating at or above 1000 volts, no conductive part of the circuit may be exposed.

As described in the lntemational Electrotechnical Commission (IEC) Standard IEC 664, digital multimeter measuring circuits

(e.g., Keithley Models l75A, 199,2000,2001, 2002, and 2010) arc Installation Category II. All other instruments signal terminals are Installation Category I and must not be connected to mains.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance limited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit fault cormnt and voltage to the card.

Before operating an instrument, make sure the line cord is coonected to a properly grounded power receptacle. Inspect the connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

For maximum safety, do not touch the product, test cables, or any other insh’oments while power is applied to the circuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting cables or jump-

ers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test fixtures. The

American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than 30V RMS. 42.4V peak, or 60VDC are present. A good safety practice is to expect

that hazardous voltage is present in any unknown circuit before tllLXSU~i”g.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the voltage being measured.

The instrument and accessories must be used in accordance with its specifications and operating instructions or the safety of the equipment may be impaired.

The WARNING heading in a manual explains dangers that might result in personal injury or death. Always read the associated information very carefully before performing the indicated procedure.

Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and operating infonnadon, and as shown on the instrument or test fixture panels, or switching card.

When fuses are used in a product, replace with same type and rating for continued protection against fire hazard.

Chassis connections must only be used as shield connections for measuring circuits,

NOT

as safety earth ground connections.

If you are using a test fixture, keep the lid closed while power is a.pplied to the device under test. Safe operation requires the use of a lid interlock.

Ifa@ screw is present, connect it to safety earth ground using the wire recommended in the user documentation.

Then

symbol on an instrument indicates that the user should E-

fer to the operating instructions located in the manual.

me A.

symbol on an instrument shows that it can source or mea-

sure 1000 volts or more, including the combined effect of normal and common mode voltages. Use standard safety precautions to avoid personal contact with these voltages.

The CAUTION heading in a manual explains hazards that could damage the instrument. Such damage may invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.

Before performing any maintenance, disconnect the line cord and all test cables,

To maintain protection from electric shock and fire, replacement components in mains circuits, including the power transformer, test leads, and input jacks, must be purchased from Keithley Instnmats. Standard fuses, with applicable national safety approvals, may be used if the rating and type are the same. Other components that are not safety related may be purchased from other suppliers as long as they are equivalent to the original component. (Note that selected parts should be purchased only through Keithley Instruments to maintain accuracy and functionality of the product.) If you are un~tre about the applicability of a replacement component, call a Keithley Instruments office for information.

To clean an instrument, use a damp cloth or mild, water based cleaner. Clean the exterior of the instrument only. Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that consist of a circuit board with no case or chassis (e.g., data acquisition board for installation into a computer) should never require cleaning if handled according to in-

structions. If the board becomes contaminated and operation is affected, the hoard should be returned to the factmy for proper cleaning/setvicing.

Rev. IO/99

MODEL 220 SPECIFICATIONS

IEEE-488 BUS IMPLEMENTATION

TABLE OF CONTENTS

Paragraph

SECTION l-GENERAL INFORMATION

1.1 Introduction ....................................

1.2

1.3 Warranty Information ............................

1.4 ManualAddenda

1.5 Safety Symbols and Terms ........................

1.6 Unpacking and Inspection .........................

1.7 Repackaging For Shipment ........................

1.8 Specifications ...................................

1.9 Accessories .....................................

1.9.1

1.9.2

2.1 Introduction ...................................

2.2 Preparation For Use .............................

^^_ -

L.L.1

2.2.2

2.3

2.3.1

2.3.2

,2.3.3

2.3.4

2.3.5

2.4

2.4.1

2.4.2

2.5

2.5.1

2.5.2

2.5.3

3.1

3.2

3.3 RecommendedTestEquipment

3.4 El

3.5.2

3.5.3 1FA end lOOnA Range Verification.

3.5.4

Features ........................................

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

Optional Accessories Supplied Accessories.

SECTION 2-OPERATION

vower-up ............................................................................

Warm-Up

Operating Instructions

Environmental Conditions Front Panel Control Descriptions AearPanelDescriptions

OutputConnector .....................................................................

InductiveLoads .......................................................................

Operation Of The Model 220.

Model 220 General Operating Procedure ExampleofOperation

Applications

Calibradon ............................................................................

ResistivityMeasurement

Diode Characterization .................................................................

SECTION 3-PERFORMANCE VERIFICATION Introduction Environmentalconditions

InitialCondltlons Performance Verification Procedure

lOOmA to 1mA Range Verification 1004 to 1OlA Range Verification

1OnA and 1nA Range Verification

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Title Page

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l-l l-l l-l 1-l 1-l l-l l-l l-l 1-2 1-2 1-2

2-1 2-1 2-l 2-l 2-l 2-1 2-1

;=t 2-4 2-5

2-5 2-5 2-9 2-9 2-9

3-l 3-l 3-l 3-1 3-1 3-1 3-2 3-2 33

4.1

4.2

4.3

4.4

4.5

4.6

SECTION 4-THEORY OF OPERATION

Introduction ..................................................................................

BlockDiagrams ................................................................................

PowerSupply .................................................................................

AnalogBoard.. Digital Board (Microcomputer).

DisplaVCircuit .................................................................................

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4-1 41 4-l 41 4-4 4-4

TABLE OF CONTENTS (CONT.1

Paragraph

SECTION S-MAINTENANCE

5.1

5.2

5.2.1

5.2.2

5.2.3

5.2.4

5.2.5

5.3

5.4

5.5

5.6

5.7 Special Handling of Static Sensitive Devices

5.8 Troubleshooting

5.8.1

5.8.2 Digital Self Test .......................

6.1

6.2

6.3

6.4

6.5 Schematic Diagrams and Component Location Drawings

Introduction Calibration

Recommended Test Equipment ..........

Environmental Conditions ...............

Warm-Up .............................

Calibration Fixtures ....................

Calibration Adjustments ................

Fuse Replacement

Line Voltage Selection Disassembly Fan Filter Maintenance

Servicing High Impedance Circuitry. ......

SECTION B-REPLACEABLE PARTS

Introduction ._.,,.......,..___......_..........._._..._._....._....._.......................... 6-l

PartsList.....................................................................................

Ordeilnglnformation...................................................................,,......, 6-l

FactoryService..........................................................................,...,.. 6-l

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Title Page

. . .

.5-l

. ...5-1

5-2 5-2 5-3

6-l

Table

2-1 2-2

3-1

3-2 5-1 5-2 5-3 54 5-5 5-6 5-7 5-8 5-9

5-10 5-11 6-l 6-2 6-3 6-4

6-5

LIST OF TABLES

Title

LineVoltageSetting Error Message Conditions

Recommended Test Equipment

lOOmA to 1mA Verification Recommended Test Equipment Calibration Fuse Replacement, 3AG Size Fuse Replacement, 5mm Size Line Voltage Selection Model 220 Static Sensitive Devices Power Supply Checks

AnalogBoardChecks

DigitalCircuitry DisplayChecks IEEE-488 Interface Board Checks Index of Modal 220 Schematic and Component Layouts Mother Board 220-103, Parts List. Display Board 220-l 13, Parts List. Analog Board 220-123, Parts List. IEEE Interface Board, 220-133. Parts List

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Page

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2-1 2-5 3-1 3-2 5-1 5-2

E 2

5-7

6-l

6-4 6-6 6-7

6-10

LIST OF ILLUSTRATIONS

Figure

l-l 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11

3-1 3-2 3-3

4-1

-i-i 4-3 5-l 5-2 5-3 5-4 6-l 6-2 6-3

6-4 6-5 6-6 6-7 6-8 6-9 6-10

Title Page

Instrument Packaging .......................................

FrontandRearPanel OutputConnector

Limiting Inductive Reaction Voltage ...........................

lOmAto2mASquareWave

Using the Model 220 External Trigger ..........................

Guarding ..................................................

Connections es a Current Sink with Resistive Load Model 220 Recommended Operating Limits Resistivity Measurement Using the Model 220 end the Model 614 Diode Characterization DiodeCurves

lOOmA to 1mA Range Verification

Test Fixture..

lFA-1nARangeVerification

Analog Circuitry Block Diagram ..................................................................

Digital Circuitry Block Diagram

MemonlMap CalibrationSetup.. Calibration Fixture

l~tolnACalibration...................................................:

MemoryChipNumberAssignment Model220ExplodedView Model220FanAssembly Display Board, Component Location Drawing. Dwg. No. 220-l 10 Mother Board, Component Location Drawing, Dwg. No. 220-100 Analog Board, Component Location Drawing, Dwg. No. 220-120 IEEE Interface Board, Component Location Drawing, Dwg. No. 220-130 Display Board, Schematic Diagram, Dwg. No. 220-l 16 Digital Circuitry, Schematic Diagram, Dwg. No. 220-106. Analog Board, Schematic Diagram, Dwg. No. 220-126 IEEE Interface Board, Schematic Diagram, Dwg. No. 220-136

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1-2 2-2

2-4 2-5 2-8 2-8 2-9 2-9 2-9 2-10 Z-10 2-10

3-2 3-3

3-3 4-2 4-3 5-4 5-1 5-2 5-2 5-5 6-2 6-3 6-11 6-13 6-17 6-21

6-23 6-25 6-29 6-33

iii/iv

SECTION 1

GENERAL INFORMATION

1.1 INTRODUCTION The Model 220 is a programmable current source with full

range current from 2nA to 100mA. The Model 220 has a selectable voltage compliance of up to 105V in one volt increments. The 100 memory locations allow up to 100 storage points for programming source, V-limit, end dwell time. The Model 220 can be used with any measurement system that uses the IEEE-488 interface bus. For detailed operating instructions of the Model 220 end the IEEE-488 bus, refer to the Model 220/230 Programming Manual.

1.2 FEATURES

The Model 220 includes the following features:

100 point buffer that is capable of storing up to 100 points of an output waveform. Programmable dwell time between the data points in the buffer when used in the single or continuous program modes. Input end output connections for external triggering located on the rear panel. Selectable voltage compliance allows operator to select the required voltage compliance. 4% digit display with appropriate exponent and decimal point.

Program modes that control the sequence between the buffer points. This is for either single, step or continuous

sequencing.

Data keyboard to enter data (V-limit, dwell time, source, etc.1 into the buffer.

Program control that has a start, stop end reset control

for the buffer end program mode.

. OPERATE button that holds the source in standby until

programmed into operate.

IEEE-488 interface bus operation isstandard. Thisenables

the Model 220 to be incorporated into a system that uses

programmed control through the IEEE-488 bus.

1.3 WARRANTY INFORMATION

Warranty information is provided on the inside front cover

of this manual. If there is a need to exercise the warranty, contact the Keithley representative in your area to determine the proper action to be taken. Keithley maintains cornplete repair and calibration facilities in the United States,

West Germany, Great Britain, France, the Netherlands,

Switzerland end Austria. Information concerning the application, operation or service of your instrument may be directed to the applications engineer et any of the above locations. Check the inside front cover of this manual for addresses.

1.4 MANUAL ADDENDA Improvements or changes to this manual will be explained

on en addendum included with this manual.

1.5 SAFETY SYMBOLS AND TERMS Safety symbols used in

The symbol

this manual are as follows:

on the instrument denotes that

the user should refer to the operating instructions. The symbol

on the instrument denotes that

1OOOV or more may be present on the terminal(s).

The WARNING used in this manual explains dangers that could result in personal injury or death.

The CAUTION used in this manual explains hazards that

could damage the instrument.

1 .6 UNPACKING AND INSPECTION

The Model 220 is inspected both mechanically and electrically before shipment. Upon receiving the Model 220 unpack all items from the shipping container and check for any obvious damage that may have occurred during transit.

Report any damage to the shipping agent. Retain end use the original packaging materials if reshipment is necessav. The following items are shipped with all Model 220 orders:

*Model 220 Programmable Current Source *Model 220 Instruction Manual *Model 6011 Triaxial Test Lead *Model 220/230 Programming Manual *Optional accessories per request.

1.7 REPACKAGING FOR SHIPMENT

The Model 220 should be packed in its original carton using the packaging method shown in Figure l-l. Before packaging, wrap the instrument in plastic. After it is placed in the

box, surround the instrument with Styrofoam packaging

material.

If the Model 220 is to be returned to Keithley Instruments for calibration or repair, include the following:

*ATTENTION REPAIR DEPARTMENT on the address label.

*Warranty status of the instrument.

*Completed service form.

1.8 SPECIFICATIONS For Model 220 detailed specifications, refer to the specifica-

tions that precede this section.

l-l

1.9 ACCESSORIES

1.9.1 Optional Accessories

INSTRUCTION

‘ROTECTIVE :ARDSOARD

rap

MODEL 220

PROTECTIVE CARDBOARD BOHOM

The following optional accessories are available from Keithley Instruments to enhance the capabilities of the Model 220.

Model 1019A Universal Rack Mounting Kit-The Model 1019A Universal Rack Mounting Kit can accomodate one or

two Model 220’s. The dimensions are 133mm x 483mm

(5%in. x 19in.I. Model 8167 Guarded Adapter-The Model 8167 Guarded

Adapter reduces effective cable capacity by driving the in-

ner shield of a triaxial cable at guard potential.

Model 7008-3 IEEE-468 Cable-The Model 7008-3 is a three foot I1 meter) IEEE488 Cable. The cable has 24 stranded wire conductors and is terminated with IEEE-488 standard connectors.

Model 70089 IEEE-488 Cable-The Model 7008-6 is a six foot I2 meter) IEEE-488 Cable. The cable has 24 stranded wire conductors and is terminated with IEEE-488 standard connectors.

Model 7010 Cable Adapter-The Model 7010 is a IEEE-488 cable adapter. The adapter extends the IEEE-488 connector

by one connector width for easy access connections.

1.9.2 Supplied Accessories

CARDBOARD STRIP

-7 CARDBOARD BOX ,

!FIL

YROFOAM PACKAGING

4TERIAL

Figure 1-l. Instrument Packaging

The following accessory is supplied with each Model 220.

Model 8011 Triax Input Cable-The Model 8011 is a three

foot (1 meter1 low noise triax cable terminated with alligator

clips at one end and a Teflon0 insulated triax connector at

the other end.

I-2

SECTION 2

OPERATION

2.1 INTRODUCTION This section includes operating instructions such as: prepara-

tion for use, environmental conditions, front and rear panel control descriptions, output connections and several examples of uass and applications of the Model 220. For Model 220 front and rear panel illustrations refer to Figure 2-l.

2.2 PREPARATION FOR USE

2.2.1 Power-Up Plug the Model 220 into the proper power receptacle in accor-

danca with Table 2-l. For fuss replacement or line switch lS102j setting refer to the maintenance section.

WARNING Ground the instrument through a properly aarth grounded racaptacla before operation. Failure to ground the instrument can result in severe injury or death in the avant of short circuit or malfunction.

Table 2-1. Line Voltage Setting

Input Voltage Switch Setting Fuse IFlOlj

5102

105V-125V I15VAC

21OV25OV 230VAC

9ov-1lOV’

18OV22OV’ 230VAC

“For instrumenta equipped with low voltage transformer

TR-187.

Immediately after turning on the Model 220 via the power switch, the display will indicate the followfng for several seconds:

116VAC ‘%A, 25OV. 3AG

%A. 25OV. 3AG %A, 25OV. 3AG

%A, 25OV. 3AG

After the software revision level is displayed, the Model 220

will display ths primary address of the instrument for approx-

imately one second. The primary address of the Model 220 is

factory set at 12.

Example:

j f

2.2.2 Warm-Up To achieve rated accuracy the Model 220 requires one hour for

warm-up.

2.3 OPERATING INSTRUCTIONS

2.3.1 Environmental Conditions Operation of the Model 220 should ba at an ambient

temperature within the range of O°C to 5O’C. up to 35°C at 70% noncondensing relative humidity. Environmental conditions for storage are from -25OC to +70°C.

2.3.2 Front Panel Controls Description Power On/Dff switch operates on the push-push principle.

Depressing this button turns the instrument on. Pushing the button again heleasingl turns the instrument off.

Display-There are four operating functions in the display

group. They are deacribad as follows.

SOURCE

Scala range of the available source current is 1.9995nA to lOl.OOmA. The source current is displayed as a 4% digit number with a single digit exponent. The least significant digit of the 4’% digit diiplay is truncated to a “0” or a “5” when the ENTER button is pressed. When a 1,2,3 or 4 is entersd ss the least Signifiwnt digit, it is truncated to a zero when the ENTER button is praaaed. When a 6, 7,8 or 9 is entered as the least

significant digit, it is truncated to a five when the ENTER button is pressed.

button selecta the source data for display. The full

1. This ia a diiplay teat. The opsretor can nota inoperative diiplay aegmenh by comparing the Model 220’s display wfth tha figure above.

2. In addition, the push button and the TALK, LISTEN, REMOTE indicators will light. All indicators will light

simultaneously if operating correctiy.

After ths display teat is complete the Model 220 will dkplay the software revision level for approximately ona second.

Emmp’e: /

During the entry of source data onto the display (cursor is

flashing), pressing the SOURCE button reverta the display to

the prekus source data. A different source current can be programrr& for each of the 100 memory locations.

V-LIMfT bumn selecta the voltage compliance for display. The compliance voltage ranges from 1V to 105V in 1V increments. The voltage compliance is displayed as a thrss digit number. The three digit number is right justified when a one or two digit number is entered and the ENTER button is pressed. The voltage compliance limiting is bipolar.

The vokage limit accuracy for output current (I,,) greater than

1nA and Issa than 1004 is f 3%1+05V). For lDyt greater than

Or equal to 1OOfi there is an additional error of 1V in the seme

2-1

2-2

Figure 2-1. Model 220 Front and Rear Panels

polarity of lout. For IOU, less than or equal to 1nA there is an additional error of 0.5V with the opposite polarity of laut

A different compliance voltage limit can be programmed for each of the 100 memory locations. During the entry of V-limit data onto the display, lcuraor is flashing) pressing the V-LIMIT button reverts the display to the previous V-limit data.

DWELL TIME button selects the dwell time data for display. Dwell time is defined as the programmed time the Model 220

spends on a specific memory location when in the single or

continuous program modes. The range of the dwell time is

3msec to SSS.%?c. The dwell time is displayed as a 4% digit

number with a single digit exponent. After the data is entered onto the display and the ENTER button is presaad, the exponent is displayed as a -3 or a 0 depending on the data entered.

An entry of zero for the dwell time, in any memory location ex-

cept the first will be interpreted as a reset in the step or con-

tinuous program modes to permit short cycling of the pro

grammed memory locations it will be interpreted as a stop in the single program mode. The dwell time accuracy listed in the

specifications requires that the IEEE-488 bus to be inactive.

A different dwell time can be programmed for each of the 100

memory locations. During the entry of dwell time data onto the

displaY (cursor is flashing), pressing the DWELL TIME button

reverts the display to the previous dwell time data. MEMORY button selects the present memory location

number for display. There are 100 available memory locations.

They start at memory location 1 and range up to Iscation 100.

The memory location is displayed es a thraa digit number. The three digit display is right justified when a one or two digit number is enterned onto the display or upon actuation of the RESET button the Model 220 selects memory location 1 as the present memory location.

Each memory location contains the source current data, V-limit data, dwell time data and tha number of the memory location. To display any of these parameters contained in a particular

memory location simply press the appropriate button (eg.

SOURCE, V-LIMIT, DWELL TIME or MEMORY). The data of

each of these parameters can vary for each memory location. This means the Model 220 can store up to 100 different values

of source current, compliance voltage or dwell time

During the entry of memory location data onto the display

(cursor is flashing), pressing the MEMORY button reverts the

display to the previously displayed memory location.

NOTE The contents of all the msmon/ locations are lost when the power to the Model 220 is turned off.

Data Entry-The three buttons contained in the data entry

group consist of the COPY, ENTER and EXPONENT buttons.

The three buttons and their functions are described as follows:

EXPONENT button allows entry of exponent data onto the display. The 5XPONENT button is active only in the source and dwell time display modes. Once the single digit exponent

data has bean entered onto the display and the ENTER button is pressed, the Model 220 places the data and the exponent into the proper notation For example, if 520.0-7 is entered on the display, it is displayed as 52.00-6 after the ENTER button is

pressed. ENTER button loads the displayed data into the present

memory location.

COPY button duplicates the source, V-limit, and dwell time data from one memory location into the next memory location. The COPY button is active only in the memory display mode.

Refer to example 5.

OUTPUT button is an alternate action control which places

the instrument in the displayed output mode. In the operate

mode, the OUTPUT LED is turned on and the source data in the present memory location is present at the output connector on the rear panel. When the instrument is not in the operate

mode, the output is programmed to .0000-S amps.

Additionally if the compliance voltage was programmed to

>32V it will be reduced (without changing displayed value) to 32V.

Program Mode-The three buttons contained in the program mode group consist of the SINGLE, CONTINUOUS and STEP

buttons. These three buttons select the possible modes of scanning the internal 100 memory locations. The bunons are described as follows:

STEP button selects the step program mode. The step program mode allows the user to manually step through the pro-

grammed memory locations using the START/STOP button. When the Model 220 is in the step program mode the STEP

LED is turned on. SINGLE button selects the single program mode. The single

program mode cycles through the programmed memory loca tions one time upon the actuation of the START/STOP button. When the Model 220 is in the single program mode the

SINGLE LED is turned on.

CONTINUOUS button selects the continuous program mode. The continuous program mode cycles through the programmed memory locations continuously upon the actuation of the

START/STOP button. When the Model 220 is in the continuous program mode ths CONTINUOUS LED is tumad on.

Program Control-The two buttons contained in the program control group are the RESET and START/STOP buttons. These two bunons control the use of the single, continuous and step program modes. The two buttons are described as follows:

RESET button is a momentary control that sets the presently displayed memory location back to memory location 1. If the Model 220 is in the operate mode, pressing the RESET button sets the output to tha source data located in memory location

1. Pressing the RESET button during the entry of data onto the

display in the Source, V-limit, dwell time or memory display

modes sets the display back to the previous displayed data. Once the data is entered onto the display and the ENTER button is pressed, pressing the RESET button reverts the instru-

ment back to the conditions in memory location 1.

2-3

START/STOP button is an alternate action control that serves two functions. The two functions are described as follows:

1. When the START/STOP button is pressed the selected pro .gram mode (step, single or continuous) is initiated.

2. When the START/STOP button is pressed a second time the START/STOP and the action of the selected program mode is stopped.

3. The START/STOP LED will be on continuously during the execution of the single of continuous program mode. In the step program mode the LED will be on the duration of the programmed dwell time.

NOTE

When the instrument is in the standby mode

(OPERATE LED is turned off), and either single or

continuous programming mode, the START/

STOP button continues to control the buffer with no output present on the Model 220. In the step mode, the START/STOP LED turns on for the

duration of the programmed dwell time.

DATA-The 12 buttons in the Data group allow entry of numerical data from 0 to 9 including with decimal point and polarity onto the display,

The TALK, LISTEN and REMOTE LED’s identify the present status of the IEEE-488 bus. For more information con-

cerning the Model 220 and the IEEE-488 bus refer to the Model 220/230 Programming Manual.

2.3.3 Rear Panel Description OUTPUT connector is Teflon@ insulated female triax con-

nector.

DIGITAL l/O port consists of four input end four output lines as well as IEEE-488 common and +5VDC. The outputs will drive one TTL load. The instrument can be programmed to generate an SRQ upon any change in the 4 bit input data.*

EXTERNAL TRIGGER INPUT initiates the selected program mode in the same manner as the START/STOP button upon receiving a TTL level negative transition with a minimum pulse

width of lO@ec.

EXTERNAL TRIGGER OUTPUT provides a negative TTL level pulse of greater than lO@ec at the completion of the programmed dwell time.

The line power fuse is rated as shown in Tables 52 and 53. The line plug mates with a 3-wire line cord which provides UL

approved connections to line power.

*For more information concerning the IEEE488 connector,

digital I/D port and primary address switches refer to the

Model 220/230 Programming Manual.

2.3.4 Output Connector The output connector is a Teflon@ insulated triax connector

which is located on the rear panel. The maximum allowable voltage potential between the HI terminal and the LO terminal is f 1OOV. The maximum allowable common mode voltage between the HI input terminal and the chassis common is 25OVrms DC to 60Hz. See Figure 2-2.

GUARD terminal provides a low impedance voltage source which is equal to the output compliance voltage. The maximum load oapcitence for the guard output is O.OlhF. The maximum load current which includes guard and output is not to exceed 106mA. The accuracy of the guard output is f 1mV excluding output lead IR voltage drops.

NOTE The guard voltage will not equal the output voltage when the instrument is at the programm-

ed V-limit overcompliance level.

OUTPUT COMMON terminal provides easy access to output common which is also the inner shield of the output connector.

mvenient connec-

IEEE-W INTERFACE connector provides bus connection to the Model 220. The connector mates with the Model 70083 and 70066 IEEE cables.*

AYY~CJJ swrcnes are use0 10 program me r ADDRESS switches are used to program the primary address

for the IEEE-488 interface bus operation. The c for the IEEE-488 interface bus operation. The primary address

is “dated only ,._^_ - -...__ .._ *

is updated only upon power-up.*

CAUTION Do not exceed the maximum common mode voltage. Instrument damage may occur.

Figure 2-2. Output Connector

23.5 Inductive Loads In general, the output load connected to the Model 220 should

be resistive. However, a small amount of inductance in the load can be tolerated but only if the inductive reaction voltage L&is limited to less than 105V. Refer to Figure 2-3 for a suggested method of limiting the inductive reaction voltage.

If the output load connected to the Model

220 is inductive, limit the inductive reaction

voltage to lass than 106V. Otherwise instrument damage may occur.

2-4

8. Program the Output to the operate mode by pressing the pressing the START/STOP

TWO SACK TO BACK LENER

DIODES. MOTOROLA ,hl,20ZS,a

Figure 2-3. Limiting inductive Reaction Voltage

2.4 OPERATION OF THE MODEL 220 The Model 220 has several diierent operating parameters.

These parameters (step, single continuous, source, V-limit, dwell time etc) are to be programmed using the following general procedure. Several examples of exact programming are given after the following.

2.4.1 Model 220 General Operating Procedure NOTE

Upon power up or upon actuation of the RESET

button the Model 220 is set to memory location 1.

1. Turn on the Model 220 and allow one hour for warm up for rated accuracy operation.

2. Select memory location.

A. Press MEMORY.

B. Press the number(s) of the desired memory location (1 to

100).

C. Press ENTER.

3. Program the desired source. A. Press SOURCE.

6. Press the numbarks) of the desired source current (.0000-9mA to lOl.OOmAI. Note that upon power-up the source is sat to .OOOO-9.

C. Press ENTER.

4. Program the appropriate V-limit. A. Press V-limit. B. Press the number(s) of the appropriate compliance

voltage limit (1 to 105V in one volt increments). Upon power-up the V-limit is set to 1V.

C. Press ENTER.

5. Program the desired dwell time.

A. Press DWELL TIME.

B. Press the number(s) of the appropriate dwell time

13msec to 999.9sec in 1 msec increments.) Upon powerup the dwell time of memory location 1 is set to 3.000-3 sec.

C. Press ENTER.

6. Select the desired program mode Istep, single or con-

tinuousl.

7. Connect appropriate load. NOTE

The output load must be noninductive. A small amount of inductance in the load can be tolerated

if the inductive reaction voltage L# is limited to less than 105V. Refer to paragraph 2.3.5.

2.4.2 Examples of Operation The following examples depict several operating levels and

conditions. Example 1 Error Message-The Model 220 will display an

error message if it is programmed into a parameter value that is outside of the range of the instrument. Table 2-2 lists the conditions that cause an error message. For example program the Model 220 for memon/ location 102.

1. Press MEMORY.

2. Press 1, 0, 2.

3. Press ENTER. After the ENTER button is pressed, the Model 220 displays the

following for approximately one second. Then the Model 220 returns to the previous display of the memory location,

Table 2-2. Erroi Message Conditions

Parameters Limits

Source

-Limit

Dwell time

/ Greater than 101 .OOmA

Greater than 105V or an entrY of 000. Greater than 999.9sec. less than 3msec.

Memory Greater than 100 or an entry of 000.

Example 2-In this example the Model 220 will be programmed to output a current of 1OmA with a 1OV compliance limit,

Required Outpur: 1OmA with 1OV compliance. Use the following procedure to program the Model 220 to out-

put the preceding parameters.

1. Select a memory location, if memory location 1 is not desired.

2. Press SOURCE, 1, 0, EXPONENT, 3. ENTER. (Programs a source value of 10mA.J

3. Press V-LIMIT, 1, 0, ENTER. (Programs 1OV V-Limit.)

4. Connect load.

5. Press OPERATE.

NOTE

If the ENTER button is not pressed in the sequence indicated, the display data will not be programmed into the appropriate marnon/ location

Upon the actuation of step 5 the Model 220 outputs 1OmA

with a 1OV compliance limit. Press the SOURCE button to

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verifY that the 1OmA was actually programmed into the Model

220. Press the V-LIMIT button to verify that the 1OV limit was actually programmed into the Model 220.

Example 3-In this example the Model 220 will be programmed to output three separate currents, three separate compliance limits, three separate dwell times and three separate memory locations. The three memory locations will be programmed in the step program mode.

Required Output: lOOpA, 1OV V-limit, 1 second dwell time,

memory location 1. ImA, 20V V-limit, 1OOmsec dwell time, memory location 2. lOmA, 30V V-limit, 2.5 second dwell time, memon/ location 3.

1. Press MEMORY, 1, ENTER. (Selects memory location 1 .I

2. Press SOURCE, 1, 0, 0, 5XPONENT. 6, ENTER. (Programs memory location 1 source for 10Oj~A.j

3. PressV-LIMIT, 1, 0, ENTER. (Programs memory location 1

V-limit for 1OV.l

4. Press DWELL TIME, 1, 5XPONENT. 0, ENTER. (Programs memory location 1 dwell time for one second.)

5. Press MEMORY, 2, ENTER (Selects memory location 2.)

6. Press SOURCE, 1, 5XPONENT. 3, ENTER. (Programs memory location 2 source for ImA.

7. Press V-LIMIT, 2,0, ENTER. (Programs memory location 2

V-limit for 2OV.j

8. Press DWELL TIME, 1, 0, 0, EXPONENT, + /-, 3, ENTER. (Programs memory location 2 dwell time for 100msec.j

9. Press MEMORY, 3, ENTER. (Selects memory location 3.1

10. Press SOURCE, 1, 0, 5XPONENT. 3, ENTER. (Programs memory location 3 source for lOmA.)

11. Press V-LIMIT, 3,0, ENTER. (Programs memon/ location 3

V-limit for 30V.J

12. Press DWELL TIME, 2, ., 5, EXPONENT, 0, ENTER. (Pro-

grams memory location 3 dwell time for 2.5sec.)

13. Press STEP. (Selects the step program mode.)

After completing step 13 the Model 220 is programmed into the parameters stated. To display any of the three programmad source values, select the desired source value’s memon/

location and press the SOURCE button. To output any of the three source values select the desired source value’s memory location, and press the OUTPUT bunon. Pressing the START/

STOP button advances the Model 220 to the next channel.

Notice that the START/STOP LED turns on for the program-

mad dwell time and then turns off. Note that actuation of

START/STOP at memory location 3 will put instrument to location 1.

Example 4-In this example the Model 220 will be programm-

ed to output five separate currents, five separate compliance

limits, five separate dwell times and five separate memon/ loca-

tions.

Required Output: lOOnA, 5V V-limit, 0.5 second dwell time,

memory location 1. lfi, 1OV V-limit, 1 second dwell time, memory location 2.

lOti, 15V V-limit, 1.5 second dwell time, memory location 3. loo@!, 20V V-limit, 2 second dwell time, memon/ location 4. lmA, 25V V-limit, 2.5 second dwell time, memory location 5.

1. Press MEMORY, 1, ENTER. (Selects memory location 1.)

2. Press SOURCE, 1, 0, 0, EXPONENT, 9, ENTER. (Programs memonl location 1 soume for lOOnA.

3. Press V-LIMIT, 5, ENTER. (Programs memory location 1 V-limit for 5V.I

4. Press DWELL TIME, .,

5, 5XPONENT. 0, ENTER. (Pro-

grams memory location 1 dwell time for 0.5 seconds.)

5. Press MEMORY, 2, ENTER. (Selects memory location 2.)

6. Press SOURCE, 1, D(PONENT, 6, ENTER. (Programs memory location 2 source for 1fi.j

7. Press V-LIMIT, 1, 0, ENTER. (Programs memory location 2

V-limit for 1OV.j

8. Press DWELL TIME, 1, 5XPONENT. 0, ENTER. (Programs

memon/ location 2 dwell time for one second.)

9. Press MEMORY, 3, ENTER. (Selects memory location 3.1

10. Press SOURCE, 1, 0, EXPONENT, 6, ENTER. (Programs memory location 3 soume for lOti.)

11. Press V-LIMIT, 1,5, ENTER. (Programs memon/ location 3 V-limit for 16V.l

12. Press DWELL TIME, 1, .,

5, D(PONENT, 0, ENTER. (Pro-

grams memory location 3 dwell time for 1.5 seconds.)

13. Press MEMORY, 4, ENTER. (Selects memory location 4.)

14. Press SOURCE, 1, 0, 0, 5XPONENT. 6, ENTER. (Programs memory location 4 soume for loo&)

15. Press V-LIMIT, 2,0, ENTER. (Programs memory location 4 V-limit for 2OV.)

16. Press DWELLTIME, 2,5XPONENT, 0, ENTER. (Programs memory location 4 dwell time for 2 seconds.)

17. Press MEMORY, 5, ENTER. (Selects memory location 5.)

19. Press SOURCE, 1, EXPONENT, 3, ENTER. (Programs memory location 5 soume for ImA.)

19. Press V-LIMIT, 2,5, ENTER. (Programs memory location 5

V-limit for 25V.)

20. Press DWELL TIMEI, ., 5, EXPONENT, 0, ENTER. (Programs memon/ location 5 dwell time for 2.5 seconds.)

After completing step 20 the Model 220 is programmed into

the parameters stated. To display any of the parameters of any memory location select the desired memory location and then select the desired parameter. To output any of the source

valuas select the desired source value’s memory location end

press the OUTPUT button.

To scan the five memory locations use the following pro-

cedure:

1. Select the program mode of scanning. (Select Single, Continuous, or Step.1

2. Select desired display mode. (Source, V-limit, dwell time or memory.)

3. Press the START/STOP bunon.

2-6

In the step program mode the user can manually step through

the programmed memory locations one at a time. Each time it

is desired to advance to the next programmed memory loca-

tion the user presses the START/STOP button. The START/

STOP LED turns on for the duration of the programmed dwell

time. When the last programmed memory location is selected

fmemory location 5 in this example) pressing the START/ STOP button reverts the instrument to memory location 1.

In the single program mode the Model 220 cycles through all the programmed memory locations one time. To start the single program mode press the START/STOP button. Once the single program mode is activated, the Model 220 starts from the present memory location and advances to each programmed memory location. The instrument remains at each memory location for the programmed dwell time and then advances to the next programmed memory location. After the

dwell time of the last programmed location the START/STOP LED turns off and the single program mode is ended. The Model 220 remains at the last programmed location until power is turned off, RESET is pressed, memory location is changed or the single or continuous program modes are ac-

tivated.

NOTE An entry of zero for the dwell time for any memory location is interpreted as a reset in the step, single and continuous program modes.

In the continuous program mode the Model 220 cycles through all the programmed mernor~ locations continuously. To start the continuous program mode press the START/

STOP button. To stop the continuous program mode press the START/STOP button a second time. When the START/

STOP button is pressed the second time the continuous program mode is stopped at the present memory location. Once the continuous program mode is activated, the Model 220 starts from the present memory location and advances to the next memory location. The instrument remains at the present memory location for the programmed dwell time (dwell time can vary for each memory location) and then advances to the next memory location. The cycle continues up to and including

the last programmed memory location and then reverts to

memarY location 1. At this point the cycle starts over again and keeps repeating until the START/STOP button is pressed, power to the instrument is turned off or the single or step prs

gram modes are selected.

Example 5-In this example the COPY button will be used to

duplicate the data of memory location 1 into memory locations 2, 3, 4 and 5. The COPY button function, when used in the memory display mode, duplicates the source, V-limit, and dwell time data of one memory location, into the next memory location. Program the following parameters into memory location 1 and use the procedure to duplicate these parameters into memory locations 2, 3, 4 and 5.

Required Parameters:

1. 10.05mA Source

2. 25V V-limit

3. 525msec Dwell Time

1. Press MEMORY, 1, ENTER. (Selects memory location 1.1

2. Press SOURCE, 1. 0. ., 0, 5, EXPONENT, 3, ENTER. (Programs memory location 1 source for 10.05mA.I

3. Press V-LIMIT, 2, 5, ENTER. (Programs memory location 1

V-limit for 25V.j

4. Press DWELL TIME, 5. 2, 5, EXPONENT, 3, ENTER. (Pro-

grams marnon/ location 1 dwell time for 525msec.j

5. Press MEMORY, COPY, COPY, COY, COPY.

The parameters specified were programmed into the Model

220 by steps 1 through 4. The parameters of memory location

1 were duplicated into metnon/ locations 2, 3, 4 and 5 by step

5. To verify that the data was duplicated into the other memory

locations select each memon/ location and select each parameter for each memory location. For example: To verii that

10.05mA was duplicated into memon/ location 3 use the

following two steps.

1. Press MEMORY, 3. ENTER. (Selects memory location 3.)

2. Press SOURCE. (Displays memory location 3 source data.) Example 6 Fabricating Output Waveforms-The Model

220 is capable of fabricating output waveforms. With the 100

memory locations the Model 220 can fabricate waveforms

with up to 100 individual steps. The following procedure is an example of programming the Model 220 to output a square wave of 1OmA to 2mA at 100Hz.

Required Output: 1OmA to 2mA square wave at 1OOHz with a

V-limit of 1OV.

NOTE

Cycle power to the instrument before starting this example to avoid confusion of previously programmed memory locations.

1. Press MEMORY, 1, ENTER. (Selects memory location 1,)

2. Press SOURCE, 1, 0, EXPONENT, 3, ENTER. (Programs memon/ location l’s V-limit for lOV.1

3. Press V-LIMIT, 1, 0, ENTER. fPrograms memory location l’s V-limit for 1OV.)

4. Press DWELL TIME, 5. EXPONENT, 3, ENTER. (Programs

memory locetion 1 dwell time for 5msec.)

5. Press MEMORY, 2, ENTER. ISelects memory location 2.)

6. Press SOURCE, 2, EXPONENT, 3, ENTER. (Programs

memory location 2 source for 2mAj.b

7. Press V-LIMIT, 1, 0, ENTER. (Programs memory location 2 V-limit for 1OV.)

6. Press DWELL TIME, 5. + I-, EXPONENT, 3, ENTER. (Programs memory location 2 dwell time for 5msec.j

9. Press CONTINUOUS, OPERATE, START/STOP.

Upon completion of step 9 the Model 220 outputs a 1OmA to

2mA 1OOHr square wave as shown in Figure 2.4.

NOTE When fabricating output wavefons ObseNe the response time specifications of the Model 220. Also, consider the affect of load imoedance on the waveform to be fabricated.

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