Agilent 8156A Operations Guide

Operating and Programming Guide

HP 8156A Attenuator

SERIAL NUMBERS

This guide applies to all instruments.

ABCDE

HP Part No. 08156-91011

Printed in the Federal Republic of Germany

First Edition

E1098

Notices

This document contains proprietary

information that is protected by

copyright. All rights are reserved.

No part of this document may be

photocopied, reproduced, or

translated to another language

without the prior written consent of

Hewlett-Packard GmbH.

c



Copyright 1996, 1998 by:

Hewlett-Packard GmbH

Herrenberger Str. 130

71034 Boeblingen

Germany

Subject Matter

The information in this document is

subject to change without notice.

Hewlett-Packard makes no warranty

of any kind with regard to this

printed material, including, but not

limited to, the implied warranties of

merchantability and tness for a

particular purpose.

Hewlett-Packard shall not be liable

for errors contained herein or for

incidental or consequential damages

in connection with the furnishing,

performance, or use of this material.

Printing History

New editions are complete revisions

of the guide reecting alterations in

the functionality of the instrument.

Updates are occasionally made to

the guide between editions. The

date on the title page changes when

an updated guide is published. To

nd out the current revision of the

guide, or to purchase an updated

guide, contact your Hewlett-Packard

representative.

Control Serial Number: First Edition

applies directly to all instruments.

Warranty

This Hewlett-Packard instrument

product is warranted against defects

in material and workmanship for a

period of one year from date of

shipment. During the warranty

period, HP will, at its option, either

repair or replace products that prove

to be defective.

For warranty service or repair, this

product must be returned to a service

facility designated by HP. Buyer shall

prepay shipping charges to HP and

HP shall pay shipping charges to

return the product to Buyer.

However, Buyer shall pay all shipping

charges, duties, and taxes for

products returned to HP from

another country.

HP warrants that its software and

rmware designated by HP for use

with an instrument will execute its

programming instructions when

properly installed on that instrument.

HP does not warrant that the

operation of the instrument,

software, or rmware will be

uninterrupted or error free.

Limitation of Warranty

The foregoing warranty shall not

apply to defects resulting from

improper or inadequate maintenance

by Buyer, Buyer-supplied software or

interfacing, unauthorized

modication or misuse, operation

outside of the environmental

specications for the product, or

improper site preparation or

maintenance.

No other warranty is expressed or

implied. Hewlett-Packard specically

disclaims the implied warranties of

Merchantability and Fitness for a

Particular Purpose.

First Edition : 1st January 1994 : 08156-91011 : E0194

: 1st June 1994 : 08156-91011 : E0694

: 1st March 1996 : 08156-91011 : E0396

: 1st June 1996 : 08156-91011 : E0696

: 1st October 1998 : 08156-91011 : E1098

Exclusive Remedies

The remedies provided herein are

Buyer's sole and exclusive remedies.

Hewlett-Packard shall not be liable

for any direct, indirect, special,

incidental, or consequential

damages whether based on contract,

tort, or any other legal theory.

Assistance

Product maintenance agreements

and other customer assistance

agreements are available for

Hewlett-Packard products.For any

assistance contact your nearest

Hewlett-Packard Sales and Service

Oce.

Certication

Hewlett-Packard Company certies

that this product met its published

specications at the time of

shipment from the factory.

Hewlett-Packard further certies

that its calibration measurements

are traceable to the United States

National Institute of Standards and

Technology, NIST (formerly the

United States National Bureau of

Standards, NBS) to the extent

allowed by the Institutes's

calibration facility, and to the

calibration facilities of other

International Standards Organization

members.

ISO 9001 Certication

Produced to ISO 9001 international

quality system standard as part of

our objective of continually

increasing customer satisfaction

through improved process control.

Safety Summary

The following general safety precautions must be observed during all phases

of operation, service, and repair of this instrument. Failure to comply with

these precautions or with specic warnings elsewhere in this manual violates

safety standards of design, manufacture

, and intended use of the instrument.

Hewlett-Packard Company assumes no liability for the customer's failure to

comply with these requirements.

General

This is a Safety Class 1 instrument (provided with terminal for

protective earthing) and has been manufactured and tested according to

international safety standards.

Operation - Before applying power

Comply with the installation section.

Additionally, the following shall be observed:

Do not remove instrument covers when operating.

Before the instrument is switched on, all protective earth terminals

, extension

cords, auto-transformers and devices connected to it should be connected to a

protective earth via a ground socket. Any interruption of the protective earth

grounding will cause a potential shock hazard that could result in serious

personal injury.

Whenever it is likely that the protection has been impaired, the instrument

must be made inoperative and be secured against any unintended operation.

Make sure that only fuses with the required rated current and of the specied

type (normal blow, time delay, etc.) are used for replacement. The use of

repaired fuses and the short-circuiting of fuseholders must be avoided.

Adjustments described in the manual are performed with power supplied to

the instrument while protective covers are removed. Be aware that energy at

many points may, if contacted, result in personal injury.

Any adjustments, maintenance, and repair of the opened instrument under

voltage should be avoided as much as possible, and when unavoidable, should

be carried out only by a skilled person who is aware of the hazard involved.

Do not attempt internal service or adjustment unless another person, capable

of rendering rst aid and resuscitation is present. Do not replace components

with power cable connected.

Do not operate the instrument in the presence of ammable gases or fumes.

Operation of any electrical instrument in such an enviroment constitutes a

denite safety hazard.

Do not install substitute parts or perform any unauthorized modication to

the instrument.

Be aware that capacitors inside the instrument may still be charged even if

the instrument has been disconnected from its source of supply.

v

Safety Symbols

The apparatus will be marked with this symbol when it is

necessary for the user to refer to the instruction manual in

order to protect the apparatus against damage.

Caution, risk of electric shock.

Frame or chassis terminal.

Protective conductor terminal.

Hazardous laser radiation.

Warning

Caution

The Models HP 8156A is a Class 1 instrument (that is, an instrument with an

exposed metal chassis directly connected to earth via the power supply cable).

The symbol used to show a protective earth terminal in the instrument is .

Before operation, review the instrument and guide, including the red safety

page, for safety markings and instructions. Consult the installation section. You

must follow these instructions and indications to ensure safe operation and to

maintain the instrument in safe condition.

The WARNING sign denotes a hazard. It calls attention to

a procedure, practice or the like, which, if not correctly

performed or adhered to, could result in injury or loss of

life. Do not proceed beyond a WARNING sign until the

indicated conditions are fully understood and met.

The CAUTION sign denotes a hazard. It calls attention to

an operating procedure, practice or the like, which, if not

correctly performed or adhered to, could result in damage to

or destruction of part or all of the equipment. Do not proceed

beyond a CAUTION sign until the indicated conditions are fully

understood and met.

vi

Warning

AC Line Power Requirements

To avoid hazardous electrical shock, do not operate the

instrument if there are any signs of damage to any portion

of the outer enclosure (covers, panels, etc.).

The HP 8156A can operate from any single-phase A

between 100V and 240V at a frequency in the range from 50 to 60Hz. The

maximum power consumption is 40VA with all options installed.

There is a fuse in this instrument. This is a T1A/250V (time-lag) (HP Part No.

2110-0007). See \Replacing the Fuse" in Appendix A for instructions on how to

change the fuse.

Line Power Cable

In accordance with international safety standards, this instrument has

a three-wire power cable. When connected to an appropriate AC power

receptacle, this cable earths the instrument cabinet. The type of power cable

shipped with each instrument depends on the country of destination. Refer to

Figure 0-1 for the part numbers of the power cables available.

C power source that supplies

Figure 0-1. Line Power Cables - Plug Identication

vii

Warning

To avoid the possibility of injury or death, you must

observe the following precautions before powering on the

instrument.

If this instrument is to be energized via an

autotransformer for voltage reduction, ensure that the

Common terminal connects to the earthed pole of the

power source.

Insert the power cable plug only into a socket outlet

provided with a protective earth contact. Do not negate

this protective action by the using an extension cord

without a protective conductor.

Before switching on the instrument, the protective

earth terminal of the instrument must be connected to a

protective conductor.You can do this by using the power

cord supplied with the instrument.

It is prohibited to interrupt the protective earth

connection intentionally.

The following work should be carried out by a qualied electrician. All local

electrical codes must be strictly observed:

If the plug on the cable does not t the power outlet, or if the cable is to be

attached to a terminal block, cut the cable at the plug end and rewire it.

The color coding used in the cable depends on the cable supplied. If you are

connecting a new plug, it should meet the local safety requirements and include

the following features:

Adequate load-carrying capacity (see table of specications).

Ground connection.

Cable clamp.

Warning

To avoid the possibility of injury or death, please note that

the HP 8156A does not have a oating earth.

viii

Warning

The HP 8156A is not designed for outdoor use.To prevent

potential re or shock hazard, do not expose the instrument

to rain or other excessive moisture.

ix

Contents

1. Getting Started

Using the Attenuator ..................... 1-1

Using the Modify Keys . . . . . . . . . . . . . . . . . . . . 1-2

Editing a Number ........ ...... ...... . 1-3

Editing a Non-Numeric Parameter ............. 1-3

Making an Attenuation Sweep .... ...... ..... .. 1-3

Making an Automatic Sweep ................. 1-3

The Manual Sweep . . . . . . . . . . . . . . . . . . . . . . .

Using your Attenuator as a Variable Back Reector ....... 1-4

Using the Through-Power Mode . . . . . . . . . . . . . . . . . 1-5

Selecting the Wavelength Calibration and Its Function ...... 1-6

2. Using the Attenuator

Setting Up the Hardware . . . . . . . . . . . . . . . . . . . . 2-1

Setting Up the Attenuation . . . . . . . . . . . . . . . . . . . 2-2

Entering the Attenuation Factor ...... ..... .... 2-2

Resetting the Attenuation Factor . . . . . . . . . . . . . . 2-3

Entering a Calibration Factor . . . . . . . . . . . . . . . . . 2-3

Editing the Calibration Factor ........ ...... . 2-3

Resetting the Calibration Factor ...... ..... .. 2-4

Transferring to the Calibration Factor . . . . . . . . . . . . 2-4

Entering the Wavelength . . . . . . . . . . . . . . . . . . . 2-4

Resetting the Wavelength ................. 2-5

Example, Setting the Calibration ...... ...... .... 2-5

1-4

3. Making an Attenuation Sweep

Conguring the Hardware ...... ...... ...... . 3-1

The Automatic Sweep ..................... 3-2

Setting Up an Automatic Sweep ...... ...... ... 3-2

Starting the Setting Up . . . . . . . . . . . . . . . . . . . 3-3

Editing the Parameters . . . . . . . . . . . . . . . . . . . 3-3

Resetting the Parameters . . . . . . . . . . . . . . . . . . 3-3

Contents-1

Executing the Automatic Sweep ............... 3-4

Repeating the Sweep . . . . . . . . . . . . . . . . . . . . 3-4

Restarting the Sweep ................... 3-4

The Manual Sweep . . . . . . . . . . . . . . . . . . . . . . . 3-5

Setting Up a Manual Sweep ...... ...... ..... 3-5

Starting the Setting Up . . . . . . . . . . . . . . . . . . . 3-5

Editing the Parameters . . . . . . . . . . . . . . . . . . . 3-5

Resetting the Parameters . . . . . . . . . . . . . . . . . . 3-6

Executing the Manual Sweep . . . . . . . . . . . . . . . . . 3-6

Changing the Attenuation in a Manual Sweep . . . . . . . . 3-7

Example,anAutomatic Attenuation Sweep .... ...... . 3-7

4. Using your Attenuator as a Variable Back Reector

Conguring the Hardware .. ...... ...... ..... 4-1

Setting Up the Software .................... 4-2

Editing the Setup ...................... 4-2

Resetting the Parameters . . . . . . . . . . . . . . . . . . 4-3

Executing the Back Reector Application . . . . . . . . . . . 4-3

Example, Setting a Return Loss . . . . . . . . . . . . . . . . . 4-4

5. Setting Up the System

Setting the HP-IB Address .. ...... ...... ..... 5-1

Resetting the HP-IB Address ................. 5-1

Selecting the HP-IB Command Set .. ...... ...... . 5-1

Resetting the Command Set .. ...... ...... ... 5-2

Selecting the Wavelength Calibration and Its Function ...... 5-2

Setting the Function of the Wavelength Calibration ...... 5-2

Resetting the Function of the Wavelength Calibration Data . . 5-3

Selecting the Wavelength Calibration Data . . . . . . . . . . . 5-3

Resetting the Wavelength Calibration Data Set . . . . . . . . 5-4

Selecting the Through-Power Mode ...... ..... .... 5-4

Deselecting the Through-Power Mode . . . . . . . . . . . . . 5-5

Resetting the Through-Power Mode . . . . . . . . . . . . . . 5-5

Setting the Display Brightness .. ...... ...... ... 5-6

Resetting the Display Brightness ............... 5-6

Selecting the Setting used at Power-On ............. 5-6

Resetting the Power-On Setting . . . . . . . . . . . . . . . . 5-6

5

Locking Out

Resetting the

4

Enb/Dis

...................... 5-7

5

4

Enb/Dis

Lock Out . . . . . . . . . . . . . . . . 5-7

Selecting the Shutter State at Power On . . . . . . . . . . . . . 5-7

Resetting the Shutter State at Power On ........... 5-7

Contents-2

Setting the Display Resolution .. ...... ...... ... 5-8

Resetting the Display Resolution ............... 5-8

6. Storing and Recalling Settings

Storing the Setting . . . . . . . . . . . . . . . . . . . . . . . 6-1

Recalling a Setting . . . . . . . . . . . . . . . . . . . . . . . 6-1

Resetting the Instrument . . . . . . . . . . . . . . . . . . . 6-1

Recalling a User Setting ................... 6-2

7. Programming the Attenuator

HP-IB Interface ........................ 7-1

Setting the HP-IB Address ...... ...... ...... . 7-3

Returning the Instrument to Local Control ........... 7-3

How the Attenuator Receives and Transmits Messages . . . . . . 7-3

How the Input Queue Works ................. 7-3

Clearing the Input Queue . . . . . . . . . . . . . . . . . . 7-4

The Output Queue . . . . . . . . . . . . . . . . . . . . . . 7-4

The Error Queue . . . . . . . . . . . . . . . . . . . . . . . 7-4

Some Notes about Programming and Syntax Diagram Conventions 7-5

Short Form and Long Form.................. 7-5

Command and Query Syntax ................. 7-5

8. Remote Commands

Units .............................

Command Summary ...................... 8-2

The Common Commands . . . . . . . . . . . . . . . . . . . . 8-5

Common Status Information ................. 8-5

SRQ, The Service Request ................. 8-6

*CLS ............................ 8-7

*ESE ............................ 8-7

*ESE? . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8

*ESR? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8

*IDN? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9

*OPC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

*OPC? ...... ...... ...... ...... .. 8-10

*OPT? .... ...... ...... ...... ..... 8-10

*RCL ............................ 8-11

*RST ............................ 8-11

*SAV ............................ 8-12

*SRE ............................ 8-13

*SRE? . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13

8-1

Contents-3

*STB? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14

*TST? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14

*WAI ...... ...... ...... ...... .... 8-15

DISPlay Commands ...................... 8-16

:DISPlay:BRIGhtness . . . . . . . . . . . . . . . . . . . . . 8-16

:DISPlay:ENABle ...................... 8-16

INPut Commands .. ...... ..... ...... .... 8-18

:INPut:ATTenuation ..................... 8-18

:INPut:LCMode ....................... 8-19

:INPut:OFFSet . . . . . . . . . . . . . . . . . . . . . . . . 8-19

:INPut:OFFSet:DISPlay . . . . . . . . . . . . . . . . . . . . 8-20

:INPut:WAVelength . . . . . . . . . . . . . . . . . . . . . . 8-20

OUTPut Commands ...... ...... ...... .... 8-22

:OUTPut:APMode ...................... 8-22

:OUTPut:POWer ....................... 8-23

:OUTPut:[:STATe] .... ...... ...... ...... 8-24

:OUTPut:[:STATe]:APOWeron . . . . . . . . . . . . . . . . . 8-25

STATus Commands . . . . . . . . . . . . . . . . . . . . . . . 8-26

:STATus:OPERation:CONDition? ............... 8-27

:STATus:OPERation:ENABle ................. 8-28

:STATus:OPERation[:EVENt]? . . . . . . . . . . . . . . . . . 8-28

:STATus:OPERation:NTRansition .... ...... ..... 8-29

:STATus:OPERation:PTRansition ...............

8-29

:STATus:QUEStionable:CONDition? .............. 8-30

:STATus:QUEStionable:ENABle . . . . . . . . . . . . . . . . 8-30

:STATus:QUEStionable[:EVENt]? ............... 8-30

:STATus:QUEStionable:NTRansition . . . . . . . . . . . . . . 8-31

:STATus:QUEStionable:PTRansition . . . . . . . . . . . . . . 8-31

:STATus:PRESet ...... ...... ...... ..... 8-32

SYSTem Commands ...... ...... ..... ..... 8-33

:SYSTem:ERRor? . . . . . . . . . . . . . . . . . . . . . . . 8-33

User Calibration Commands ...... ...... ...... 8-34

Entering the User Calibration Data .. ...... ...... 8-34

:UCALibration:STARt ................... 8-35

:UCALibration:STATe.................... 8-36

:UCALibration:STOP . . . . . . . . . . . . . . . . . . . . 8-36

:UCALibration:VALue ................... 8-37

Contents-4

9. Programming Examples

Example 1 - Checking Communication ............. 9-2

Example 2 - Status Registers and Queues ............ 9-3

Example 3 - Measuring and Including the Insertion Loss ..... 9-7

Example 4 - Running an Attenuation Sweep . . . . . . . . . . . 9-11

A. Installation

Safety Considerations ..................... A-1

Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . A-1

AC Line Power Supply Requirements ........ ...... A-2

Line Power Cable ...... ...... ..... ..... A-2

Replacing the Battery .................... A-3

Replacing the Fuse . . . . . . . . . . . . . . . . . . . . . . A-4

Operating and Storage Environment ........ ...... A-5

Temperature . . . . . . . . . . . . . . . . . . . . . . . . . A-5

Humidity .......................... A-6

Instrument Positioning and Cooling . . . . . . . . . . . . . . A-6

Switching on the Attenuator ...... ...... ...... A-6

Monitor Output .. ...... ...... ...... .... A-7

Optical Output . . . . . . . . . . . . . . . . . . . . . . . . . A-7

Disabling the Optical Output .... ...... ...... . A-7

HP-IB Interface ........................ A-8

Connector . . . . . . . . . . . . . . . . . . . . . . . . . .

HP-IB Logic Levels . . . . . . . . . . . . . . . . . . . . . .

Claims and Repackaging .................... A-9

Return Shipments to HP ................... A-9

A-8

A-9

B. Accessories

Instrument and Options .................... B-1

HP-IB Cables and Adapters . . . . . . . . . . . . . . . . . . . B-2

Connector Interfaces and Other Accessories . . . . . . . . . . . B-2

Straight Contact Connector . . . . . . . . . . . . . . . . . . B-2

Option 201, Angled Contact Connector ............ B-4

C. Specications

Denition of Terms .. ...... ...... ..... ... C-1

Specications ......................... C-3

Supplementary Performance Characteristics . . . . . . . . . . C-5

Operating Modes . . . . . . . . . . . . . . . . . . . . . . C-5

General . . . . . . . . . . . . . . . . . . . . . . . . . . C-6

Environmental ...................... C-6

Contents-5

Power: .... ...... ...... ...... .... C-7

Other Specications ...................... C-8

Declaration of Conformity ................... C-9

D. Performance Tests

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

Equipment Required . . . . . . . . . . . . . . . . . . . . . . D-1

Test Record .......................... D-3

Test Failure .......................... D-3

Instrument Specication .................... D-3

Performance Test .... ...... ...... ...... . D-4

I. Total Insertion Loss Test .................. D-4

II. Linearity/Attenuation Accuracy Test ............ D-7

III. Attenuation Repeatability Test .............. D-9

IV. Return Loss Test ...... ...... ...... ... D-9

Options 100, 101, and 121 .... ...... ...... . D-9

Options 201 and 221 . . . . . . . . . . . . . . . . . . . . D-12

V.Polarization Dependent Loss (PDL): Optional ......... D-15

Polarization Dependant Loss Test (Mueller method) ...... D-16

E. Cleaning Procedures

Cleaning Materials . . . . . . . . . . . . . . . . . . . . . . .

Cleaning Fiber/Front-Panel Connectors ............. E-2

Cleaning Connector Interfaces ................. E-2

Cleaning Connector Bushings . . . . . . . . . . . . . . . . . . E-3

Cleaning Detector Windows .................. E-3

Cleaning Lens Adapters ...... ...... ...... .. E-3

Cleaning Detector Lens Interfaces ............... E-4

E-1

F. HP-IB Overview

HP 8157A HP-IB Command Summary . . . . . . . . . . . . . . F-1

Dierences .......................... F-1

G. Error Messages

Display Messages ........ ...... ...... ... G-1

HP-IB Messages ........ ...... ...... .... G-2

Command Errors . . . . . . . . . . . . . . . . . . . . . . . G-2

Execution Errors ........ ...... ...... .. G-5

Device-Specic Errors .................... G-6

Query Errors ........................ G-7

Instrument Specic Errors .................. G-8

Contents-6

Index

Contents-7

Figures

0-1. Line Power Cables - Plug Identication ............ vii

1-1. The Attenuator Keys . . . . . . . . . . . . . . . . . . . . . 1-2

1-2. The Modify Keys . . . . . . . . . . . . . . . . . . . . . . . 1-2

1-3. The Parameters for an Automatic Sweep ........... 1-3

1-4. The Hardware Conguration for the Back Reector (Options 201

and 203) . . . . . . . . . . . . . . . . . . . . . . . . .

2-1. The Hardware Conguration for the Attenuator . . . . . . . .

2-2. The Attenuation Factor on the Display ...... ...... 2-2

2-3. The Calibration Factor on the Display . . . . . . . . . . . . .

2-4. The Wavelength on the Display . . . . . . . . . . . . . . . .

2-5. Hardware Conguration for Attenuation Example - A .... . 2-6

2-6. Hardware Conguration for Attenuation Example - B .. ... 2-7

3-1. The Hardware Conguration for the Attenuator . . . . . . . . 3-1

3-2. The Parameters for an Automatic Sweep ........... 3-2

3-3. Selecting the Automatic Sweep Application .......... 3-3

3-4. Running the Automatic Sweep ................ 3-4

3-5. Editing the

STOP

Parameter .. ...... ...... ... 3-5

3-6. Running the Manual Sweep . . . . . . . . . . . . . . . . . . 3-6

4-1. The Hardware Conguration for the Back Reector ...... 4-1

4-2. Editing the Value for the Reference Return Loss . . . . . . . . 4-3

4-3. Executing the Back Reector Application . . . . . . . . . . . 4-4

4-4. Hardware Conguration for Variable Return Loss ....... 4-4

5-1. The

5-2. The

LAMBDCAL

USERCAL

Indicator on the Display . . . . . . . . . . . . 5-3

Indicator on the Display .. ...... .... 5-4

5-3. The Display in Through-Power Mode ...... ...... . 5-5

6-1. The Display when Recalling the Default Setting ........ 6-2

8-1. Common Status Registers . . . . . . . . . . . . . . . . . . . 8-6

8-2. The Status Registers . . . . . . . . . . . . . . . . . . . . . 8-27

9-1. Hardware Conguration for Attenuation Example - A .... . 9-7

9-2. Hardware Conguration for Attenuation Example - B .. ... 9-8

A-1. Line Power Cables - Plug Identication ............ A-2

A-2. Rear Panel Markings . . . . . . . . . . . . . . . . . . . . . A-3

1-4

2-1

2-3

2-5

Contents-8

A-3. Releasing the Fuse Holder .................. A-4

A-4. The Fuse Holder . . . . . . . . . . . . . . . . . . . . . . . A-5

A-5. Correct Positioning of the Attenuator . . . . . . . . . . . . . A-6

A-6. HP-IB Connector . . . . . . . . . . . . . . . . . . . . . . . A-8

B-1. Straight Contact Connector Conguration . . . . . . . . . . . B-3

B-2. Angled Contact Connector Conguration ........... B-4

D-1. Total Insertion Loss Test Setup 1, Options 100, 101, 121 .... D-5

D-2. Total Insertion Loss Test Setup 1, Options 201, 221 . . . . . . . D-5

D-3. Total Insertion Loss Test Setup 1, Option 350 ......... D-6

D-4. Total Insertion Loss Test Setup 2, Options 100, 101, 121 .... D-6

D-5. Total Insertion Loss Test Setup 2, Options 201, 221 . . . . . . . D-7

D-6. Total Insertion Loss Test Setup 2, Option 350 ......... D-7

D-7. Return Loss Test Setup 1 (see also the text above), Options 100,

101, 121 . . . . . . . . . . . . . . . . . . . . . . . . . D-10

D-8. Return Loss Test Setup 2, Options 100, 101 ...... .... D-11

D-9. Return Loss Test Setup 2, Option 121 ............. D-12

D-10. Return Loss Test Setup 1 (see also the text above), Options 201,

221 .... ...... ...... ...... ..... D-12

D-11. Return Loss Test Setup 2, Option 201 ............. D-14

D-12. Return Loss Test Setup 2, Option 221 ............. D-14

D-13. PDL Test Setup 1: Reference Measurement .......... D-16

D-14. PDL Test Setup 2: Power after DUT . . . . . . . . . . . . . . D-22

Contents-9

Tables

7-1. HP-IB Capabilities .. ...... ...... ...... .. 7-2

8-1. Units and Allowed Mnemonics ................ 8-1

8-2. Common Command Summary . . . . . . . . . . . . . . . . . 8-2

8-3. Command List . . . . . . . . . . . . . . . . . . . . . . . . 8-3

8-4. Reset State (Default Setting) ................. 8-12

A-1. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . A-5

C-1. ............................... C-3

C-2. Monitor Output Options ................... C-4

C-3. Multimode Options . . . . . . . . . . . . . . . . . . . . . .

D-1. Equipment for the PDL test .. ...... ...... ... D-15

D-2. Performance Test HP 8156A ................. D-24

F-1. Settings (Listener Function) ................. F-2

F-2. Interrogating Settings (Talker Function) . . . . . . . . . . . . F-3

F-3. Status and Error Reporting (Talker Function) .... ..... F-4

F-4. Universal Commands . . . . . . . . . . . . . . . . . . . . . F-5

C-5

Contents-10

Getting Started

This chapter introduces the features of the HP 8156A. More detail is given on

these features in the following chapters.

The main features of the HP 8156A, other than its use as an attenuator, are its

built-in sweep and back reector applications, its through-power mode (which

displays the power at the output of the instrument, rather than the amount of

attenuation set) and its selection of wavelength calibration possibilities

Using the Attenuator

.

1

1

Note

Set the attenuation of the lter using

and

4

5

(calibration factor).

Cal

Before using the instrument, you should make sure that it is

properly warmed up. The instrument is properly warmed up

when it has been switched on for a minimum of 45 minutes.

Failure to do this can cause errors of up to 0.04dB in the

attenuation.

5

(attenuation factor),

4

Att

45

(wavelength),

Getting Started 1-1

1

Figure 1-1. The Attenuator Keys

The attenuation factor and the calibration factor set the position of the lter.

The calibration factor allows you to oset the value of the attenuation factor.

Att(dB)=Cal(dB)+Attenuation

5

In addition, you can use

the calibration factor.

Using the Modify Keys

There are four modify keys on the front panel of the attenuator.

4

Disp!Cal

Figure 1-2. The Modify Keys

to transfer the current attenuation factor to

lter

(dB)

1-2 Getting Started

Editing a Number

Use

4(5

and

4)5

to move the cursor from digit to digit when editing a number.

Use

4*5

and

4+5

to change the value of a digit when editing a number.

Editing a Non-Numeric Parameter

Use

Use

4*5or4)5

4+5or4(5

to increment the parameter.

to decrement the parameter.

Making an Attenuation Sweep

There are two types of attenuation sweep, automatic and manual.

Making an Automatic Sweep

An automatic sweep is one where stepping from one attenuation factor to the

next is done by the instrument.

1

To select the automatic sweep press

AUTO

. By pressing

the sweep.

START

4

5

repeatedly you view and can edit the parameters for

Swp

is the attenuation factor at which the sweep begins,

the attenuation factor that ends the sweep,

factor change, and

DWELL

is the time taken for each attenuation factor.

4

5

, and make sure that

Swp

STEP

Figure 1-3. The Parameters for an Automatic Sweep

If you have set up your sweep, then you press

SWEEP

is set to

is the size of the attenuation

5

to run it.

4

Exec

Getting Started 1-3

STOP

is

1

The Manual Sweep

A manual sweep is one where stepping from one attenuation factor to the next

is done by the user

To select the manual sweep press

MANUAL

. By pressing

for the sweep.

STOP

is the attenuation factor that ends the sweep, and

.

START

5

, and make sure that

4

Swp

5

repeatedly you can view and edit the parameters

4

Swp

SWEEP

is set to

is the attenuation factor at which the sweep begins,

STEP

is the size of the

attenuation factor change.

If you have set up your sweep, then you press

next attenuation factor in the sweep, press

attenuation factor in the sweep, press

4

+

5or4

4

5

Exec

4*5or4)5

5

.

(

to run it. To go to the

.To go to the previous

Using your Attenuator as a Variable Back Reector

Note

Before using the instrument, you should make sure that it is

properly warmed up. The instrument is properly warmed up

when it has been switched on for a minimum of 45 minutes.

Failure to do this can cause errors of up to 0.04dB in the

attenuation.

To use the attenuator as a back reector, you need to set up the hardware as

shown in the gure below.

Figure 1-4.

The Hardware Conguration for the Back Reector (Options 201 and 203)

Press

4

Back Re

measured values for the insertion loss of the attenuator (

5

to start operation as a back reector.You need to enter

INS LOSS

), the return

1-4 Getting Started

1

loss of the attenuator (

(

RL REF

RL(dB)=0

). The return loss (RL) is calculated according to the equation

10log(10

RL INPUT

0

RLInput(dB

10

), and the reference return loss you are using

0

(2(

)

+(1010

0

RLInput(dB

10

)

)10

Att(dB)+InsLoss(dB

10

))+

RLRef(dB

You edit the value for the return loss while the application is running.

Using the Through-Power Mode

Note

Before using the instrument, you should make sure that it is

properly warmed up. The instrument is properly warmed up

when it has been switched on for a minimum of 45 minutes

.

Failure to do this can cause errors of up to 0.04dB in the

attenuation.

In the through-power mode, the instrument shows the power that gets through

the attenuator on the display (that is the power at the output) rather than the

attenuation.

When you select the through-power mode the attenuation factor (in dB)

becomes the value for the through-power (in dBm).

Set the calibration factor (see \Entering a Calibration Factor" in Chapter 2) to

get the attenuation factor to the value of the through-power

.

))

)

After measuring and setting this base power value, press

until

THRUPOWR

is shown at the bottom of the display. SelectONto select the

through-power mode.

Edit the through-power factor by pressing

4

5

, and then the Modify keys.

Att

4

Syst

5

repeatedly

Getting Started 1-5

1

Selecting the Wavelength Calibration and Its Function

The attenuation at any point on the lter is wavelength dependent. This

dependence is measured and stored in the instrument, and is used, with

the value for the wavelength entered by the user to compensate for the

dependence. This is the wavelength calibration data.

There are two ways in which this data can be used:

to reposition the lter so that the attenuation stays constant, or

to change the attenuation factor on the display to show the wavelength

dependence.You use this to set the wavelength for an unknown source (you

alter the wavelength until the displayed attenuation matches the measured

attenuation).

To set the function of the calibration data press

is shown at the bottom of the display. Set

LAMBDCALtoOFF

calibration data to reposition the lter, and set

repeatedly until

4

Syst

to use the

LAMBDCALtoON

LAMBDCAL

to use the

5

calibration data to change the attenuation factor.

As well as the wavelength calibration data measured for and stored in your

instrument in the factory, there is space reserved in memory for a set of your

own user calibration data. (You load this data into the instrument over the

HP-IB. See \User Calibration Commands" in Chapter 8)

Press

4

5

repeatedly until

Syst

OFF

selects the factory-made wavelength calibration data.

USERCAL

is shown at the bottom of the display.

wavelength calibration data.

1-6 Getting Started

ON

selects the user

Using the Attenuator

This chapter describes the use of the HP 8156A as an attenuator. There is an

example given at the end of this chapter.

Setting Up the Hardware

To use the attenuator, you need to set up the hardware as shown in the gure

below.

2

2

Figure 2-1. The Hardware Conguration for the Attenuator

Note

The connector interface you need depends on the connector type you are using

(see \Connector Interfaces and Other Accessories" in Appendix B).

If you have option 121, then the Monitor Output provides a signal for

monitoring the power getting through the attenuator. The signal level is

approximately 5% of the output power level. For the most accurate results,

Before using the instrument, you should make sure that it is

properly warmed up. The instrument is properly warmed up

when it has been switched on for a minimum of 45 minutes.

Failure to do this can cause errors of up to 0.04dB in the

attenuation.

Using the Attenuator 2-1

2

you should measure the coupling ratio, and its wavelength dependence, for the

Monitor Output yourself.

Setting Up the Attenuation

The attenuation can be set in two dierent ways. This section describes how to

set the attenuation by specifying the attenuation factor and an oset (called a

calibration factor).

\Selecting the Through-Power Mode" in Chapter 5 describes how to set the

attenuation by specifying the power that gets through.

Entering the Attenuation Factor

The attenuation factor is shown at the top left of the display

.

Figure 2-2. The Attenuation Factor on the Display

Edit the attenuation factor using the modify keys.

The lter attenuation is changed while you edit the attenuation factor according

to the equation:

Att

lter

(dB)=

Att(dB)0

Cal(dB

) (1)

To edit the attenuation factor,

5

1. press

4

Att

, and

2. edit the factor using the Modify keys (see \Using the Modify Keys" in

Chapter 1).

2-2 Using the Attenuator

Resetting the Attenuation Factor

To reset the attenuation factor, press and hold

4

5

until the value resets (this

Att

takes approximately two seconds). The attenuation factor resets so that the

lter attenuation is zero, that is

2

Att(dB)=Cal(dB

)

Entering a Calibration Factor

The calibration factor is shown at the bottom left of the display

Figure 2-3. The Calibration Factor on the Display

This factor does not aect the lter attenuation. It is used to oset the values

for the attenuation factor.

There are two ways of entering the calibration factor.

by editing, and

by transferring

Editing the Calibration Factor

You would use this, for example, to enter an oset to compensate for the

insertion loss (attenuation) of your hardware setup.

The lter attenuation stays constant while you edit the calibration factor.

This means that the attenuation factor, shown on the display, changes according

to the formula below (from equation (1)):

Att

NEW

(dB)=

Att

lter

(dB)+

Cal

NEW

(dB)=

Att

(dB)0Cal

OLD

OLD

(dB)+

Cal

NEW

(dB)

To edit an external calibration factor,

1. press

4

Cal

5

, and

2. edit the factor using the Modify keys (see \Using the Modify Keys" in

Chapter 1).

Using the Attenuator 2-3

2

Resetting the Calibration Factor.

hold

4

5

until the value resets to zero (this takes approximately two seconds).

Cal

To reset the calibration factor, press and

The calibration factor resets to zero.

Transferring to the Calibration Factor

You can transfer the attenuation factor shown on the display into the calibration

factor, so that the attenuation factor is reset to zero.

You would use this, for example, after you have set the power through the

attenuator at a specic level. When you have reset the attenuation factor, you

can edit it to get a relative attenuation.

The lter attenuation stays constant when you transfer to the calibration factor.

This means that the new calibration factor is calculated from the attenuation

factor and the old calibration factor according to the formula below (from

equation (1)):

Cal

To transfer to the calibration factor, press

(dB)=0Att

NEW

lter

(dB)=

Cal

OLD

4

Disp!Cal

(dB)0Att

5

.

OLD

(dB)

Entering the Wavelength

The attenuation at any point on the lter is wavelength dependent.

This dependence is measured and stored in the instrument, and is used, with

the value for the wavelength entered by the user, to compensate for the

dependence. This is the wavelength calibration data.

Note

There are two ways of using the wavelength calibration data,

to reposition the lter so that the attenuation stays

constant, or

to change the attenuation factor on the display to show the

wavelength dependence.You use this to set the wavelength

for an unknown source (you alter the wavelength until the

displayed attenuation matches the measured attenuation).

There are two sets of wavelength calibration data, one made

in the factory, individually, for your instrument. The user

denes the other.

2-4 Using the Attenuator

For more details on these topics, see \Selecting the Wavelength

Calibration and Its Function" in Chapter 5.

2

The wavelength is shown at the top right of the display

Figure 2-4. The Wavelength on the Display

Edit the wavelength using the modify keys.

To edit the wavelength,

5

1. press

2. edit the value using the Modify keys (see \Using the Modify Keys" in

Chapter 1).

Resetting the Wavelength

To reset the wavelength, press and hold

approximately two seconds). The wavelength resets to 1310nm.

4



, and

4

5

until the value resets (this takes

Att

.

Example, Setting the Calibration

This example uses the HP 8156A Attenuator, with a HP 8153A multimeter with

one source and one sensor. The connectors for this system are all HMS-10.

We set up the hardware, and measure the insertion loss of the system and use

this value to set a calibration factor.

1. Congure the hardware as shown in the gure below, making sure that all

the connectors are clean:

Using the Attenuator 2-5

2

Figure 2-5. Hardware Conguration for Attenuation Example - A

a. Make sure that the power sensor is installed in the multimeter mainframe

in channel A, and the source is in channel B.

b. Connect both instruments to the electric supply.

c. Switch on both instruments.

Note

Under normal circumstances you should leave the instruments

to warmup. (The multimeter needs around 20 minutes to

warmup. The attenuator needs around 45 minutes with the

shutter open to warmup.) Warming up is necessary for accuracy

of the sensor, and the output power of the source.

d. Connect a patchcord from the source to the input of the sensor.

2. Measure the insertion loss of the Hardware setup:

a. On the multimeter:

i. Set the wavelength for the sensor to that of the source.

ii. Activate the source, by pressing the gray button on its front panel.

iii. Start the loss application (press

4

Mode

5

and then

4

Loss

5

b. Recongure the hardware to include the attenuator:

i. Disconnect the source from the sensor, and connect it to the input of

the attenuator.

, and

4

Exec

5

).

2-6 Using the Attenuator

Figure 2-6. Hardware Conguration for Attenuation Example - B

ii. Connect a patchcord from the output of the attenuator to the sensor.

c. Set the wavelength on the attenuator to that of the source:

5

i. Press

.

4



ii. Use the modify keys to edit the value for the wavelength.

2

d. Reset the calibration factor, by pressing and holding

e. Reset the attenuation factor, by pressing and holding

f. Enable the output of the attenuator (press

4

Enb/Dis

4

5

for two seconds.

Cal

5

for two seconds.

4

Att

5

so that the LED lights).

g. Note the value for the loss read by the multimeter.

3. Enter the insertion loss of the hardware setup.

a. Press

4

Cal

5

.

b. Edit the calibration factor so that it has the value shown on the

multimeter display, using the modify keys.

You should notice that the value for the attenuation factor changes, and always

has the same value as that for the calibration factor. This is because the

lter attenuation stays at zero (you should also notice that the display on the

multimeter does not change).

The attenuator now shows its full attenuation (including its own insertion loss)

on the display.

Using the Attenuator 2-7

3

Making an Attenuation Sweep

This chapter describes how to make an attenuation sweep with the HP 8156A

Attenuator. An example is given at the end of the chapter.

Conguring the Hardware

To use the attenuator for a sweep, you need to set up the hardware as shown

in the gure below. (This is the conguration as given for simple attenuation in

chapter 2).

Figure 3-1. The Hardware Conguration for the Attenuator

Note

Before using the instrument, you should make sure that it is

properly warmed up. The instrument is properly warmed up

when it has been switched on for a minimum of 45 minutes.

Failure to do this can cause errors of up to 0.04dB in the

attenuation.

3

The connector interface you need depends on the connector type you are using

(see \Connector Interfaces and Other Accessories" in Appendix B).

If you have option 121 (the monitor output), then the Monitor Output provides a

signal for monitoring the power getting through the attenuator. The signal level

is approximately 5% of the output power level. For the most accurate results,

Making an Attenuation Sweep 3-1

you should measure the coupling ratio, and its wavelength dependence, for the

Monitor Output yourself.

3

The Automatic Sweep

An automatic sweep is one where stepping from one attenuation factor to the

next is done by the instrument.

Setting Up an Automatic Sweep

There are four parameters for the automatic sweep

START

STOP

If

is the attenuation factor at which the sweep begins

is the attenuation factor that ends the sweep.

START

and

STEP

are such that the sweep does not end exactly at

.

STOP

,

then the sweep ends at the immediately previous value.

STEP

is the size of the attenuation factor change. This value is always

positive, even for a sweep of decreasing attenuation factor.

set to a value greater than the dierence between

DWELL

Note

is the time taken for each attenuation factor.

The dwell time includes the time it takes for the lter

START

and

STEP

STOP

cannot be

.

attenuation to change. The time taken to change depends on

the size of the attenuation factor change, and is in the range 20

to 400ms (typical value is 200ms).

Figure 3-2. The Parameters for an Automatic Sweep

3-2 Making an Attenuation Sweep

Starting the Setting Up

To select the automatic sweep

1. Press

2. If it is not already set, use

4

Swp

5

.

4*5or4+5

Figure 3-3. Selecting the Automatic Sweep Application

Editing the Parameters

To edit the value of the parameters

3. Press

4. Edit the value of

5. Press

6. Edit the value of

7. Press

8. Edit the value of

9. Press

4

Swp

4

Swp

4

Swp

4

Swp

5

5

5

5

again to get

START

again to get

STOP

again to get

STEP

again to get

START

with the Modify keys.

STOP

.

with the Modify keys.

STEP

.

with the Modify keys.

DWELL

to set

SWEEPtoAUTO

.

3

.

.

10. Edit the value of

DWELL

with the Modify keys.

See \Using the Modify Keys" in Chapter 1 for information on editing with the

Modify keys.

Resetting the Parameters

To reset any of the sweep parameters, press and hold

4

5

until the value resets

Swp

(this takes approximately two seconds).

START

and

STOP

reset so that the lter attenuation (inside the instrument) is

zero, that is

Start=Cal

or

Making an Attenuation Sweep 3-3

Stop=Cal

See \Entering a Calibration Factor" in Chapter 2 for information about setting

the calibration factor, Cal.

STEP

resets to zero.

3

DWELL

resets to 0.2 seconds.

Executing the Automatic Sweep

If you have just set up your sweep, then you only need to press

4

Exec

5

to run the

application.

If you have already set up the sweep, and are currently operating the

instrument as an attenuator,

5

1. Press

2. Press

, and then,

4

Swp

5

4

Exec

.

Figure 3-4. Running the Automatic Sweep

If there is something wrong with a parameter (if

STEP

is zero, for example), this

parameter is shown on the display for editing. Edit the parameter, and press

4

5

again.

Exec

Repeating the Sweep

When the sweep is nished (

display), you can press

SWEEP READY

4

5

to start it again.

Exec

is shown at the bottom of the

Restarting the Sweep

To restart the sweep at any time while it is running, press

3-4 Making an Attenuation Sweep

4

Exec

5

.

The Manual Sweep

A manual sweep is one where stepping from one attenuation factor to the next

is done by the user

.

Setting Up a Manual Sweep

There are three parameters for a manual sweep

START

STOP

If

is the attenuation factor at which the sweep begins.

is the attenuation factor that ends the sweep.

START

and

STEP

are such that the sweep does not end exactly at

then the sweep ends at the immediately previous value.

STEP

is the size of the attenuation factor change. This value is always

positive, even for a sweep of decreasing attenuation factor.

set to a value greater than the dierence between

START

Starting the Setting Up

To select the manual sweep

1. Press

2. If it is not already set, use the modify keys to set

4

Swp

5

.

SWEEPtoMANUAL

Editing the Parameters

To edit the value of the parameters

3. Press

4. Edit the value of

4

Swp

5

again to get

START

START

.

with the Modify keys.

and

STEP

STOP

STOP

,

cannot be

.

.

3

5. Press

4

Swp

5

again to get

6. Edit the value of

STOP

.

STOP

with the Modify keys.

Figure 3-5. Editing the

STOP

Parameter

Making an Attenuation Sweep 3-5

7. Press

4

Swp

5

again to get

STEP

.

8. Edit the value of

STEP

with the Modify keys.

See \Using the Modify Keys" in Chapter 1 for information on editing with the

Modify keys.

3

Resetting the Parameters

To reset any of the sweep parameters, press and hold

4

5

until the value resets

Swp

(this takes approximately two seconds).

START

and

STOP

reset so that the lter attenuation (inside the instrument) is

zero, that is

Start=Cal

or

Stop=Cal

See \Entering a Calibration Factor" in Chapter 2 for information about setting

the calibration factor, Cal.

STEP

resets to zero.

Executing the Manual Sweep

If you have just set up your sweep, then you only need to press

4

Exec

5

to run the

application.

If you have already set up the sweep, and are currently operating the

instrument as an attenuator,

1. Press

2. Press

4

5

, and then,

Swp

4

5

Exec

.

Figure 3-6. Running the Manual Sweep

3-6 Making an Attenuation Sweep

If there is something wrong with a parameter (if

STEP

is zero, for example), this

parameter is shown on the display for editing. Edit the parameter, and press

4

5

again.

Exec

Changing the Attenuation in a Manual Sweep

To go to the next attenuation factor in the sweep, press

To go to the previous attenuation factor in the sweep, press

4*5or4)5

4+5or4(5

.

.

Example,anAutomatic Attenuation Sweep

This example uses the HP 8156A Attenuator on its own.

We set up the instrument to sweep from 5dB to 0dB with an interval of 0.5dB,

dwelling for a second at each attenuation factor.

1. First we want to reset the instrument.

Note

If someone else is using this instrument, please check with them

before resetting, or store their setting for later recall.

a. Press

b. Press

4

Recall

4

Exec

5

.

5

.

2. Start the automatic sweep application.

a. Press

4

Swp

5

.

3

b. If the sweep parameter is set to

3. Set the start attenuation factor.

5

a. Press

b. Use the Modify keys to set

4

Swp

.

START

4. Set the attenuation factor step size.

a. Press

4

5

, to get the stop parameter.We do not need to edit this

Swp

parameter.

b. Press

4

5

to get the step parameter.

Swp

MANUAL

, press

to 5.000dB.

4*5

,or

4+5

to set it to

AUTO

Making an Attenuation Sweep 3-7

.

c. Use the Modify keys to set

STEP

to 0.500dB.

5. Set the dwell time

a. Press

4

Swp

b. Use the Modify keys to set

3

6. Execute the sweep

a. Press

4

Swp

b. Make sure the output is enabled (press

c. Press

4

Exec

.

5

.

DWELL

5

.

5

.

to 1.00s.

4

Enb/Dis

5

until the LED lights).

3-8 Making an Attenuation Sweep

4

Using your Attenuator as a Variable Back

Reector

This chapter describes how you can use your attenuator as a variable back

reector. An example using the back reector kit (option 203 with option 201) is

given at the end of the chapter.

Conguring the Hardware

To use the attenuator as a back reector, you need to set up the hardware as

shown in the gure below.

4

Note

Note

If this your rst time to use the attenuator as a back reector

you rst need to make some measurements. These require other

setups before setting up the hardware as shown below (see

\Setting Up the Software").

Figure 4-1. The Hardware Conguration for the Back Reector

Before using the instrument, you should make sure that it is

properly warmed up. The instrument is properly warmed up

when it has been switched on for a minimum of 45 minutes.

Failure to do this can cause errors of up to 0.04dB in the

attenuation.

Using your Attenuator as a Variable Back Reector 4-1

,

If you are not using option 201, the connector interfaces you need depends on

the connector type you are using. Option 121 (the monitor output) is of no

use when using the attenuator as a back reector. The disruption to the back

reection performance by leaving this output open is negligible, though you may

want to terminate it to eliminate any small eect it might have.

Setting Up the Software

There are four factors that inuence the back reection of the attenuator.

4

These are

1. the insertion loss of the attenuator (

INS LOSS

),

2. the return loss of the attenuator (

3. the reference return loss you are using (

RL INPUT

RL REF

),

), and

4. the lter attenuation.

The return loss (RL) is calculated according to the equation

RL(dB)=0

10log(10

0

RLInput(dB

10

)

+(1010

0

RLInput(dB

10

)

)10

Att(dB)+InsLoss(dB

))+

RLRef(dB

10

0

(2(

You edit the values for the insertion loss, the reference return loss, and the

return loss of the attenuator while you are setting up the application.

You edit the value for the return loss while the application is executing. The

instrument calculates and sets the required value for the lter attenuation.

Editing the Setup

Before you start setting up the back reector application, you may need to

measure the following values, if you do not already know them:

The insertion loss of the instrument (see \Example, Setting the Calibration"in

Chapter 2,

The return loss of the instrument (with the output properly terminated), and

The reference return loss value.

To start setting up the Back Reector application

))

)

1. Press

After pressing this the rst parameter (

4

Back Re

5

.

INS LOSS

4-2 Using your Attenuator as a Variable Back Reector

) is ready to for editing.

2. Edit the value insertion loss with the Modify keys.

3. Press

4

Back Re

5

.

4. Edit the value reference return loss with the Modify keys.

Figure 4-2. Editing the Value for the Reference Return Loss

5

5. Press

4

Back Re

.

6. Edit the value attenuator return loss with the Modify keys.

See \Using the Modify Keys" in Chapter 1 for information on editing with the

Modify keys.

Resetting the Parameters

To reset any of the back reector parameters, press and hold

4

Back Re

5

until the

value resets (this takes approximately two seconds).

INS LOSS

RL REF

resets to 2.000dB.

resets to 14.700dB (the return loss for the glass/air interface at an open

connector)

4

RL INPUT

resets to 60.000dB.

Executing the Back Reector Application

If you have just set up the application, then you only need to press

4

Exec

5

the application.

If you have already set up the application, and are currently operating the

instrument as an attenuator,

5

5

.

, and then,

1. Press

2. Press

4

Back Re

4

Exec

Using your Attenuator as a Variable Back Reector 4-3

to run

Figure 4-3. Executing the Back Reector Application

The value shown at the top left of the display is the return loss of the

instrument. You can edit the value of the return loss with the Modify keys.

4

Example, Setting a Return Loss

This example uses the HP 8156A Attenuator with options 201, and 203.

Assuming an insertion loss of 2.00dB and a return loss of 60.000dB for the

instrument we set up the instrument to have a return loss of 20dB.

1. Congure the hardware as shown in the gure below:

Figure 4-4. Hardware Conguration for Variable Return Loss

a. Connect the instrument to the electric supply.

b. Switch on the instrument.

2. Reset the instrument.

4-4 Using your Attenuator as a Variable Back Reector

Note

a. Press

b. Press

If someone else is using this instrument, please check with them

before resetting, or store their setting for later recall.

5

.

4

Recall

5

.

4

Exec

3. Set the return loss reference value for the HP 81000BR reference reector

a. Press

4

Back Re

twice to select the

RL REF

parameter.

5

b. Edit the value, with the Modify keys to set it to 0.180dB

4. Press

4

5

to start the application

Exec

5. Edit the return loss value, with the Modify keys, to set it to 20.000dB.

.

4

Using your Attenuator as a Variable Back Reector 4-5

Setting Up the System

This chapter describes how to set the various system parameters for your

attenuator.

Setting the HP-IB Address

To set the HP-IB address of the attenuator

5

1. Press

4

Syst

.

5

5

2. Edit the value for

ADDRESS

using the Modify keys.

Resetting the HP-IB Address

To reset

ADDRESS

, press and hold

4

5

until the value resets (this takes

Syst

approximately two seconds).

ADDRESS

resets to 28.

Selecting the HP-IB Command Set

The instrument has two command sets for programming over the HP-IB. The

rst one based on the Standard Commands for Programmable Instruments

(SCPI). The second simulates the command set of the HP 8157A Optical

Attenuator.

To select the command set to use

5

1. Press

repeatedly until

4

Syst

2. Select the command set using the Modify keys.(

command set;

8157SIM

COMMANDS

is shown at the bottom of the display.

is the 8157 simulation.)

8156SCPI

is the SCPI

Setting Up the System 5-1

3. You need to cycle the power (switch the instrument o, and then back on

again) for the chosen command set to become active.

Resetting the Command Set

To reset

COMMANDS

, press and hold

4

5

until the value resets (this takes

Syst

approximately two seconds).

You need to cycle the power (switch the instrument o, and then back on again)

for the chosen command set to become active.

COMMANDS

resets to

8156SCPI

.

Selecting the Wavelength Calibration and Its Function

The attenuation at any point on the lter is wavelength dependent. This

5

dependence is measured and stored in the instrument, and is used, with

the value for the wavelength entered by the user to compensate for the

dependence. This is the wavelength calibration data.

As well as the wavelength calibration data measured for and stored in your

instrument in the factory, there is space reserved in memory for a set of your

own user calibration data.

There are two choices concerning the use of wavelength calibration data.

Whether or not the data should be used to position the lter to compensate

for wavelength dependence.

Whether the factory-made wavelength calibration data is used, or the data

entered by the user.

Setting the Function of the Wavelength Calibration

This compensation can be used

to reposition the lter so that the attenuation stays constant, or

to change the attenuation factor on the display to show the wavelength

dependence.You use this to set the wavelength for an unknown source (you

alter the wavelength until the displayed attenuation matches the measured

attenuation).

To set the function of the wavelength calibration data

5-2 Setting Up the System

1. Press

4

5

repeatedly until

Syst

LAMBDCAL

is shown at the bottom of the display.

2. Select the wavelength calibration data function using the Modify keys.

Set

LAMBDCALtoOFF

so that the function of the wavelength calibration data

is not visible to the user. This keeps the attenuation value xed, and alters

the lter position.

Set

LAMBDCALtoON

to keep the lter position xed, and for the function of

the wavelength calibration data to be visible to the user.

While it isON,

is shown if the

LAMBDCAL

USERCAL

is shown at the bottom left of the display (

is also on).

Figure 5-1. The

LAMBDCAL

U/L-CAL

Indicator on the Display

Resetting the Function of the Wavelength Calibration Data

To reset

LAMBDCAL

, press and hold

4

5

until the value resets (this takes

Syst

approximately two seconds).

LAMBDCAL

resets to

OFF

.

Selecting the Wavelength Calibration Data

You enter the user wavelength calibration data over the HP-IB (see \User

Calibration Commands" in Chapter 8).

Using your own wavelength calibration data, you can use the attenuator

to compensate for the total wavelength dependence of your hardware

conguration.

5

Note

If you are using the instrument in an environment where the

temperature changes, you should not use the user wavelength

calibration data, as it lacks correction for temperature changes.

To select the wavelength calibration data to use

1. Press

4

5

repeatedly until

Syst

USERCAL

is shown at the bottom of the display.

Setting Up the System 5-3

2. Select the wavelength calibration data using the Modify keys

OFF

means that the instrument uses the factory-made wavelength

calibration data

ON

means that the user wavelength calibration data is used.

.

While it isON,

(

U/L-CAL

5

Resetting the Wavelength Calibration Data Set

To reset

USERCAL

USERCAL

is shown if the

Figure 5-2. The

, press and hold

is shown at the bottom left of the display

LAMBDCAL

USERCAL

4

Syst

is also on).

Indicator on the Display

5

until the value resets (this takes

approximately two seconds).

USERCAL

resets to

OFF

.

Selecting the Through-Power Mode

In the through-power mode, the instrument shows the power that gets through

the attenuator on the display (that is the power at the output) rather than the

attenuation.

When you select the through-power mode the attenuation factor (in dB)

becomes the value for the through-power (in dBm).

That is, if the attenuation factor is at 32.000dB, and you switch the absolute

power mode on, then the base value for the through-power is 32.000dBm.

Measure the power at the output of the attenuator, and then use the calibration

factor (see \Entering a Calibration Factor" in Chapter 2) to set the attenuation

factor to the required value for use as the base value for the through-power

0

Cal

New

=(

ThroughPower

Base

Att)+Cal

Current

After setting the calibration factor,

5-4 Setting Up the System

1. Press

4

5

repeatedly until

Syst

THRUPOWR

is shown at the bottom of the display.

2. SelectONto switch on the through-power mode.

The through-power factor is shown at the upper left on the display, and you can

edit it by pressing

4

5

, and using the Modify keys (see \Using the Modify Keys"

Att

in Chapter 1).

Figure 5-3. The Display in Through-Power Mode

Deselecting the Through-Power Mode

When you switch the through-power mode o, the last set calibration factor

becomes active, and the attenuation factor is set so that the lter attenuation

does not change.

1. Press

2. Select

4

5

repeatedly until

Syst

OFF

to switch o the through-power mode.

THRUPOWR

is shown at the bottom of the display.

Resetting the Through-Power Mode

To reset

THRUPOWR

, press and hold

4

5

until the value resets (this takes

Syst

approximately two seconds).

THRUPOWR

resets to

OFF

.

5

Setting Up the System 5-5

Setting the Display Brightness

This parameter sets the brightness of the display

5

1. Press

repeatedly until

4

Syst

2. Use Modify keys to set the brightness

BRIGHT

is shown at the bottom of the display.

.

.To set the brightness,

Resetting the Display Brightness

5

To reset

BRIGHT

, press and hold

until the value resets (this takes

4

Syst

approximately two seconds).

BRIGHT

5

Selecting the Setting used at Power-On

resets to full brightness.

This parameter selects the instrument setting that is used at power-on.

1. Press

repeatedly until

4

Syst

P ON SET

is shown at the bottom of the display.

5

2. Use Modify keys to select the setting.

LAST

is the setting that was in use when the instrument was switched o.

DEFAULT

is the default setting.

a number is the number of the setting location where the user has saved a

setting.

Resetting the Power-On Setting

To reset

PONSET

press and hold

4

Syst

5

approximately two seconds).

PONSET

is reset to

LAST

.

5-6 Setting Up the System

until the value resets (this takes

Locking Out

4

Enb/Dis

5

This selects how the shutter enabling and disabling key operates while the

instrument is being operated over the HP-IB

5

1. Press

repeatedly until

4

Syst

SHUTTER

.

is shown at the bottom of the display.

2. Use Modify keys to select the setting.

NORMAL

4

Enb/Dis

LOCKOUT

means that the shutter can be enabled and disabled as usual with

5

.

means that the shutter cannot be enabled or disabled (Local Lock

Out) while the instrument is being operated over the HP-IB.

Resetting the

To reset

SHUTTER

4

Enb/Dis

5

Lock Out

, press and hold

5

until the value resets (this takes

4

Syst

approximately two seconds).

SHUTTER

resets to

NORMAL

.

Selecting the Shutter State at Power On

This selects whether the shutter is open or closed at power-on.

1. Press

4

5

repeatedly until

Syst

SHUTTER@ PON

is shown at the bottom of the

display.

2. Use Modify keys to select the setting.

DIS

means that the shutter is disabled at power-on.

LAST

means that the shutter is the set to the state that was in use when

the instrument was switched o.

5

Resetting the Shutter State at Power On

5

To reset

SHUTTER@ PON

press and hold

until the value resets (this takes

4

Syst

approximately two seconds).

SHUTTER@ PON

resets to

LAST

.

Setting Up the System 5-7

Setting the Display Resolution

This parameter sets the resolution of the attenuation factor and the calibration

factor on the screen.

5

1. Press

2. Use Modify keys to select the setting.

repeatedly until

4

Syst

RESOLUT

is shown at the bottom of the display.

1/100

1/1000

Resetting the Display Resolution

To reset

approximately two seconds).

RESOLUT

5

sets a resolution of 0.01.

sets a resolution of 0.001.

RESOLUT

resets to

, press and hold

1/100

.

4

5

until the value resets (this takes

Syst

5-8 Setting Up the System

6

Storing and Recalling Settings

This chapter describes how to store instrument settings to memory, and how to

recall them.

A setting consists of the wavelength, calibration and attenuation factors, all the

application parameters, and the system parameters with the exceptions of the

display resolution, the power on setting, and the HP-IB address and command

set.

Storing the Setting

To store the current instrument setting

5

1. Press

2. Select the location where you want to store the setting, using the

4+5

.

4

Store

.

4*5

or the

6

3. Press

4

Exec

5

.

Recalling a Setting

Resetting the Instrument

To reset the instrument, you should recall the default setting

1. Press

4

Recall

DEFAULT

location is shown on the display.

5

. The

Storing and Recalling Settings 6-1

Figure 6-1. The Display when Recalling the Default Setting

2. Press

Recalling a User Setting

To recall a setting that is stored

1. Press

2. Select the location from which you want to recall the setting, using the

3. Press

6

the

4

+

4

Exec

4

Recall

5

.

4

Exec

5

.

5

.

4*5

or

5

.

6-2 Storing and Recalling Settings

Programming the Attenuator

This chapter gives general information on how to control the attenuator

remotely. Descriptions for the actual commands for the attenuator are given

in the following chapters. The information in these chapters is specic to the

attenuator, and assumes that you are already familiar with programming the

HP-IB.

HP-IB Interface

7

The interface used by the attenuator is the HP-IB (Hewlett-P

ackard Interface

Bus).

This is the interface used for communication between a controller and an

external device, such as the attenuator. The HP-IB conforms to IEEE standard

488-1978, ANSII standard MC 1.1 and IEC recommendation 625-1.

If you are not familiar with the HP-IB, then refer to the following books:

Hewlett-Packard Company.

Bus

, 1987.

The International Institute of Electrical and Electronics Engineers.

Tutorial Description of Hewlett-Packard Interface

IEEE

Standard 488.1-1987, IEEE Standard Digital Interface for Programmable

Instrumentation

The International Institute of Electrical and Electronics Engineers.

. New York, NY, 1987

IEEE

Standard 488.2-1987, IEEE Standard Codes,Formats, Protocols and Common

Commands For Use with ANSI/IEEE Std 488.1-1987

. New York, NY, 1987

To obtain a copy of either of these last two documents, write to:

The Institute of Electrical and Electronics Engineers, Inc.

345 East 47th Street

New York, NY 10017

USA.

Remote Operation 7-1

7

In addition, the commands not from the IEEE-488.2 standard, are dened

according to the Standard Commands for Programmable Instruments (SCPI).

For an introduction to SCPI, and SCPI programming techniques, refer to the

following documents:

Hewlett-Packard Press (Addison-Wesley Publishing Company, Inc).

Beginners Guide to SCPI

The SCPI Consortium.

Published periodically by various publishers.To obtain a copy of this manual,

contact your Hewlett-Packard representative.

The attenuator interfaces to the HP-IB as dened by the IEEE Standards 488.1

and 488.2. The table shows the interface functional subset that the attenuator

implements.

Mnemonic Function

SH1 Complete source handshake capability

AH1 Complete acceptor handshake capability

T6 Basic talker; serial poll; unaddressed to talk if addressed to listen

L4 Basic listener; unaddressed to listen if addressed to talk; no listen only

SR1 Complete service request capability

RL1 Complete remote/local capability

PP0 No parallel poll capability

DC1 Device clear capability

7

DT0 No device trigger capability

C0 No controller capability

. Barry Eppler. 1991.

Standard Commands for Programmable Instruments

Table 7-1. HP-IB Capabilities

A

.

7-2 Remote Operation

Setting the HP-IB Address

You can only set the HP-IB address from the front panel. See \Setting the HP-IB

Address" in Chapter 5.

The default HP-IB address is 28.

Returning the Instrument to Local Control

If the instrument has been operated in remote the only keys you can use are

NNNNNNNNNNNNNNNN

N

Local

NNNNNNNNNNNNNNNN

N

Local

a and

4

does not operate if local lockout has been enabled.

Enb/Dis

5

. The

disables the output from the attenuator.

set to

LOCKOUT

(see \Locking Out

NNNNNNNNNNNNNNNN

N

Local

key returns the instrument to local control.

5

enables and

SHUTTER

4

Enb/Dis

5

4

Enb/Dis

5

" in Chapter 5).

does not operate if

4

Enb/Dis

is

How the Attenuator Receives and Transmits Messages

The attenuator exchanges messages using an input and an output queue. Error

messages are kept in a separate error queue.

How the Input Queue Works

The input queue is a FIFO queue (rst-in rst-out). Incoming bytes are stored in

the input queue as follows:

1. Receiving a byte:

a. Clears the output queue.

b. Clears Bit 7 (MSB).

2. No modication is made inside strings or binary blocks. Outside strings and

binary blocks, the following modications are made:

7

a. Lower-case characters are converted to upper-case.

b. The characters 0016to 0916and 0B16to 1F16are converted to spaces

(2016).

c. Two or more blanks are truncated to one.

Remote Operation 7-3

3. An EOI (End Or Identify) sent with any character is put into the input queue

as the character followed by a line feed (LF,0A

only one LF is put into the input queue.

4. The parser starts if the LF character is received or if the input queue is full.

Clearing the Input Queue

Switching the power o, or sending a Device Interface Clear signal, causes

commands that are in the input queue, but have not been executed to be lost.

The Output Queue

The output queue contains responses to query messages. The attenuator

transmits any data from the output queue when a controller addresses the

instrument as a talker.

Each response message ends with a LF (0A16), with EOI=TRUE. If no query is

received, or if the query has an error, the output queue remains empty.

The Message Available bit (MAV, bit 4) is set in the Status Byte register

whenever there is data in the output queue.

The Error Queue

The error queue is 30 errors long. It is a FIFO queue (rst-in rst-out). That is,

the rst error read is the oldest error to have occurred. A new error is only put

into the queue if it is not already in it.

). If EOI is sent with a LF,

16

If more than 29 errors are put into the queue, the message '-350<Queue

7

Overow>' is placed as the last message in the queue.

7-4 Remote Operation

Some Notes about Programming and Syntax Diagram

Conventions

A program message is a message containing commands or queries that you send

to the attenuator. The following are a few points about program messages:

You can use either upper-case or lower-case characters.

You can send several commands in a single message. Each command must be

separated from the next one by a semicolon (;).

You end a program message with a line feed (LF) character, or any character

sent with End-Or-Identify (EOI).

You can use any valid number/unit combination.

Example

1500nm, 1.5m and 1.5e-6m are all equivalent.

If you do not specify a unit, then the default unit is assumed. The default

unit for the commands are given with command description in the next

chapter.

Short Form and Long Form

The instrument accepts messages in short or long forms

message

message is

:INPUT:WAVELENGTH 1313

:INP:WAV 1313

.

is in long form, the short form of this

.For example, the

In this manual the messages are written in a combination of upper and lower

case. Upper case characters are used for the short form of the message.For

example, the above command would be written

:INPut:WAVelength

.

The rst colon can be left out for the rst command or query in your message.

That is, the example given above could also be sent as

INP:WAV 1313

.

Command and Query Syntax

All characters not between angled brackets must be sent exactly as shown.

The characters between angled brackets (<...>) indicate the kind of data that

you send, or that you get in a response.You do not type the angled brackets in

the actual message. Descriptions of these items follow the syntax description.

The most common of these are:

7

string is ascii data. A string is contained between a " at the start and the

end, or a ' at the start and the end.

Remote Operation 7-5

value is numeric data in integer (12), decimal (34.5) or exponential format

(67.8E-9).

wsp is a white space.

Other kinds of data are described as required.

The characters between square brackets ([ . . . ]) show optional information that

you can include with the message.

The bar (j) shows an either-or choice of data, for example,ajbmeans eitheraor

b

, but not both simultaneously.

Extra spaces are ignored; they can be inserted to improve readability.

7

7-6 Remote Operation

8

Remote Commands

This chapter gives a list of the remote commands, for use with the HP-IB.

Besides this command set, the HP 8156A can simulate the command set of

the HP 8157A. A summary of the commands for the HP 8157A is given in

Appendix F. How to select the command set is described in \Selecting the HP-IB

Command Set" in Chapter 5.

In the remote command descriptions the parts given in upper-case characters

must be given. The parts in lower-case characters can also be given, but they

are optional.

Units

The units and all the allowed mnemonics are given in the table below.

Table 8-1. Units and Allowed Mnemonics

Unit Default Allowed Mnemonics

deciBel

deciBel/1mW

meter

DB DB

DBM DBM DBMW

M PM,NM,UM,MM,M

Where units are specied with a command, only the Default is shown, by the

full range of mnemonics can be used.

Remote Commands 8-1

8

Command Summary

Table 8-2. Common Command Summary

Command Parameter/Response Min Max Function

*CLS

*ESE

*ESE?

*ESR?

*IDN?

*OPC

*OPC?

*OPT?

*RCL

*RST

*SAV

*SRE

*SRE?

*STB?

*TST?

*WAI

<

value

<

value

<

value

<

string

<

value

<

string

<

location

<

location

<

value

<

value

<

value

<

value

Clear Status Command

>

>

>

>

0 255 Standard Event Status Enable Command

0 255 Standard Event Status Enable Query

0 255 Standard Event Status Register Query

Identication Query

Operation Complete Command

>

>

>

0 9 Recall Instrument Setting

Operation Complete Query

Options Query

Reset Command

>

>

>

>

>

1 9 Save Instrument Setting

0 255 Service Request Enable Command

0 255 Service Request Enable Query

0 255 Read Status Byte Query

0 65535 Self Test Query

Wait Command

8

8-2 Remote Commands

Table 8-3. Command List

Command Parameter

:DISPlay

:BRIGhtness

:BRIGhtness?

<

<

:DISPlay

:ENABle OFFjONj0j1

:ENABle? 0j1

value

value

Response

>

>

Unit Min Max Default

0 1

:INPut

:ATTenuation

:ATTenuation?

:ATTenuation? MIN

:ATTenuation? DEF

:ATTenuation? MAX

<

<

<

<

<

:INPut

:LCMode OFFjONj0j1

:LCMode? 0j1

:INPut

:OFFSet

<

:DISPlay

:OFFSet?

:OFFSet? MIN

:OFFSet? DEF

:OFFSet? MAX

<

<

<

<

:INPut

:WAVelength

:WAVelength?

:WAVelength? MIN

:WAVelength? DEF

:WAVelength? MAX

<

<

<

<

<

:OUTPut

:APMode OFFjONj0j1

:APMode? 0j1

:OUTPut

:POWer

:POWer?

:POWer? MIN

:POWer? DEF

:POWer? MAX

<

<

<

<

<

value>j

value

>

value

>

value

>

value

>

value>j

value

>

value

>

value

>

value

>

value>j

value

>

value

>

value

>

value

>

value>j

value

>

value

>

value

>

value

>

MINjDEFjMAX DB

DB

DB

DB

DB

MINjDEFjMAX DB

DB

DB

DB

DB

MINjDEFjMAX M

M

M

M

M

MINjDEFjMAX DBM

DBM

DBM

DBM

DBM

0.000dBy60.000dBy0.000dB

-99.999dB 99.999dB 0.000dB

1200nm 1650nm 1310nm

y

0.000dB

60.000dBy0.000dB

y

8

y

Remote Commands 8-3

Table 8-3. Command List (continued)

Command Parameter

:OUTPut

[

:STATe

[

:STATe?

]

]

OFFjONj0j1

0j1

:APOWeron DISjLASTj0j1

:APOWeron? 0j1

:STATus

:OPERation

[

:EVENt]?

:CONDition?

:ENABle

:ENABle?

:NTRansition

:NTRansition?

:PTRansition

:PTRansition?

<

<

<

<

<

<

<

<

value

value

value

value

value

value

value

value

:QUEStionable

[

:EVENt]?

:CONDition?

:ENABle

:ENABle?

:NTRansition

:NTRansition?

:PTRansition

:PTRansition?

<

<

<

<

<

<

<

<

value

value

value

value

value

value

value

value

:PRESet

Response

Unit Min Max Default

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

:SYSTem

:ERRor?

<

value

>

-32768 32767

:UCALibration

:STARt

:STARt?

<

start value>,<step value>M,M

<

start value>,<step value>,<no of steps

1200nm,0.01nm

z

>

M,M

:STATe OFFjONj0j1

:STATe? 0j1

8

:STOP

:VALue

:VALue?

y

These are specied minimum and maximum values, with the calibration factor

(

:INPut:OFFSet

<

value

<

value

>

>

DB

-99.999dB 99.999dB

DB

) set to zero.Actual values depend on the instrument, and the

calibration factor.

8-4 Remote Commands

z

These values are interdependent

1650

nm

The Common Commands

The IEEE 488.2 standard has a list of reserved commands, called common

commands. These are the commands that start with an asterisk. Some of these

commands must be implemented by any instrument using the standard, others

are optional. This section describes the implemented commands.

Common Status Information

There are four registers for the common status information. Two of these are

status-registers and two are enable-registers. These registers conform to the

IEEE Standard 488.2-1987

under \*ESE", \*ESR?", \*SRE", and \*STB?".

The following gure shows how the registers are organized.

.You can nd further descriptions of these registers

start value

+((

number of step01)2step val ue)

Remote Commands 8-5

8

Figure 8-1. Common Status Registers

*

The questionable and operation status trees are described in \STATus

Commands".

Note

8

SRQ, The Service Request

A service request (SRQ) occurs when a bit in the Status Byte register goes from

0!1

The Request Service (RQS) bit is set to1at the same time that the SRQ is

caused. This bit can only be reset by reading it by a serial poll. The RQS bit is

8-6 Remote Commands

AND the corresponding bit in the Service Request Enable Mask is set.

Unused bits in any of the registers return 0 when you read

them.

not aected by the condition that caused the SRQ. The serial poll command

transfers the value of the Status Byte register to a variable.

*CLS

Syntax

Denition

Example

*ESE

Syntax

Denition

*CLS

The *CLS command clears the following:

Error queue

Standard event status register (ESR)

Status byte register (STB)

After the

*CLS

command the instrument is left waiting for the

next command. The instrument setting is unaltered by the

command, though

If the

*CLS

command occurs directly after a program message

*OPC/*OPC?

actions are canceled.

terminator, the output queue and MAV, bit 4, in the status byte

register are cleared, and if condition bits 2-0 of the status byte

register are zero, MSS, bit 6 of the status byte register is also

zero.

OUTPUT 728;"*CLS"

*ESE<wsp><value

>

0value255

The

*ESE

command sets bits in the standard event status enable

register (ESE) that enable the corresponding bits in the standard

event status register (ESR).

The register is cleared:

At power-on

By sending a value of zero

The register is not changed by the

*RST

and

*CLS

commands.

Remote Commands 8-7

8

*ESE?

BIT MNEMONIC BIT VALUE

7 Power On 128

6 User Request 64

5 Command Error 32

4 Execution Error 16

3 Device dependent Error 8

2 Query Error 4

1 Request Control 2

0 Operation Complete 1

The Event Status Enable Register

The standard event status enable query returns the contents of

the standard event status enable register.

Example

*ESR?

Syntax

Denition

8

8-8 Remote Commands

OUTPUT 728;"*ESE 21"

OUTPUT 728;"*ESE?"

ENTER 728; A$

*ESR?

The standard event status register query returns the contents of

the standard event status register. The register is cleared after

being read.

0contents255

BITS MNEMONICS BIT VALUE

7 Power On 128

6 User Request 64

5 Command Error 32

4 Execution Error 16

3 Device Dependent Error 8

2 Query Error 4

1 Request Control 2

0 Operation Control 1

The Standard Event Status Register

Example

*IDN?

Syntax

Denition

Example

OUTPUT 728;"*ESR?"

ENTER 728; A$

*IDN?

The identication query commands the instrument to identify

itself over the interface.

Response:

HEWLETT-PACKARD, HP8156A, mmmmmmmmmm, n.nn

HEWLETT-PACKARD

HP8156A

mmmmmmmmmm

: manufacturer

: instrument model number

: serial number (not supplied)

n.nn

: rmware revision level

DIM A$ [100]

OUTPUT 728;"*IDN?"

ENTER 728; A$

8

Remote Commands 8-9

*OPC

Syntax

Denition

*OPC?

Example

*OPT?

Syntax

Denition

*OPC

The instrument parses and executes all program message units

in the input queue and sets the operation complete bit in the

standard event status register (ESR). This command can be used

to avoid lling the input queue before the previous commands

have nished executing.

This query causes all the program messages in the input queue

to be parsed and executed. Once it has completed it places an

ASCII '1' in the output queue. There is a short delay between

interpreting the command and putting the '1' in the queue.

OUTPUT 728;"*CLS;*ESE 1;*SRE 32"

OUTPUT 728;"*OPC"

OUTPUT 728;"*CLS;*ESE 1;*SRE 32"

OUTPUT 728;"*OPC?"

ENTER 728;A$

*OPT?

This query returns a string with the options installed in the

attenuator. There are three elds, separated by commas.Ifan

option is not present in the instrument, the corresponding eld

returns a

"0"

.

The three elds are

High Return Loss

High Performance, Monitor Output,

.For example, if you have option 201 (High

performance, high return loss version), the string returned is

8

Example

High Performance, 0, High Return Loss

OUTPUT 728;"*OPT?"

.

ENTER 728;A$

8-10 Remote Commands

*RCL

Syntax

Denition

Example

*RST

Syntax

Denition

*RCL<wsp

><

location

>

0location9

An instrument setting from the internal RAM is made the actual

instrument setting (this does not include HP-IB address or

parser, the attenuation resolution or the power on setting).

You recall user settings from locations 1-9. See \*SAV". Location

0 contains the default setting, which is the same as that

obtained by

*RST

.

OUTPUT 728;"*RCL 3"

*RST

The reset setting (default setting) stored in ROM is made the

actual setting.

Instrument state: the instrument is placed in the idle state

awaiting a command.

The following are not changed:

HP-IB (interface) state

Instrument interface address

Output queue

Service request enable register (SRE)

Standard event status enable register (ESE)

The commands and parameters of the reset state are listed in

the following table.

Remote Commands 8-11

8

Table 8-4. Reset State (Default Setting)

Parameter Reset Value

Attenuation Factor 0dB

Calibration Factor 0dB

Wavelength 1310nm

Sweep Manual

Start 0.00dB

Stop 0.00dB

Step 0.00dB

Dwell 0.2s

Back Re. Ins. Loss 2.00dB

RL Ref 14.70dB

RL-Input 60.00dB



Cal O

User Cal O

Through Power Mode O

Display Brightness Full

Power On Setting Last

Shutter enable under HP-IB Normal

Shutter at Power ON Disabled

Resolution 1/100

Example

OUTPUT 728;"*RST"

*SAV

Syntax

*SAV<wsp

><

location

>

1location9

Denition

The instrument setting is stored in RAM. You can store settings

in locations 1-9. The scope of the saved setting is identical with

the scope of the standard setting described in \*RST".

8

Example

OUTPUT 728;"*SAV 3"

8-12 Remote Commands

*SRE

Syntax

Denition

*SRE<wsp

><

value

>

0value255

The service request enable command sets bits in the service

request enable register that enable the corresponding status

byte register bits.

The register is cleared:

At power-on

By sending a value of zero.

The register is not changed by the

*RST

and

*CLS

commands.

BITS MNEMONICS BIT VALUE

7 Operation Status 128

6 Request Status 64

5 Event Status Byte 32

4 Message Available 16

3 Questionable Status 8

2 Not used 0

1 Not used 0

0 Not used 0

Note

*SRE?

The Service Request Enable Register

Bit 6 cannot be masked.

8

The service request enable query returns the contents of the

service request enable register.

Remote Commands 8-13

Example

*STB?

OUTPUT 728;"*SRE 48"

OUTPUT 728;"*SRE?"

ENTER 728; A$

Syntax

Denition

Example

*STB?

The read status byte query returns the contents of the status

byte register.

0contents255

BITS MNEMONICS BIT VALUE

7 Operation Status 128

6 Request Service 64

5 Event Status Byte 32

4 Message Available 16

3 Questionable Status 8

2 Not used 0

1 Not used 0

0 Not used 0

The Status Byte Register

OUTPUT 728;"*STB?"

ENTER 728; A$

8

*TST?

Syntax

Denition

*TST?

The self-test query commands the instrument to perform a

self-test and place the results of the test in the output queue.

Returned value: 0value65535. This value is the sum of

the results for the individual tests

8-14 Remote Commands

BITS MNEMONICS BIT VALUE

8 Counter 256

7 Analog to Digital Converter 128

6 General DSP Hardware 64

5 DSP Timeout 32

4 DSP Communications 16

3 Calibration Data Corrupt 8

2 Keypad 4

1 Battery RAM 2

0 Calibration Data

Not Present/ Checksum Fail 1

The Self Test Results

So 16 would mean that the DSP (Digital Signal Processor)

Communications had failed, 18 would mean that the DSP

Communications had failed, and so had the Battery RAM. A

value of zero indicates no errors.

No further commands are allowed while the test is running.

Example

*WAI

Syntax

Denition

Example

The instrument is returned to the setting that was active at the

time the self-test query was processed.

The self-test does not require operator interaction beyond

sending the

*TST?

query.

OUTPUT 728;"*TST?"

ENTER 728; A$

*WAI

The wait-to-continue command prevents the instrument from

executing any further commands, all pending operations are

completed.

OUTPUT 728;"*WAI"

Remote Commands 8-15

8

DISPlay Commands

:DISPlay:BRIGhtness

Syntax

Description

:DISPlay:BRIGhtness<wsp

This command sets the brightness of the display. The brightness

is a oating point number in the range 0 (least bright) to 1

(brightest). There are seven possible levels of intensity. The

value input for the brightness is rounded to the closest of these

seven values.

The default brightness is 1.

:DISPlay:BRIGhtness?

Syntax

Description

:DISPlay:BRIGhtness?

The query returns the brightness of the display, where 0 means

least brightness, and 1 means full brightness.

Example

OUTPUT 728;":DISP:BRIG 0.5"

OUTPUT 728;":DISP:BRIG?"

ENTER 728;A$

:DISPlay:ENABle

Syntax

Description

:DISPlay:ENABle<wsp>OFFjONj0j1

This command enables or disables the front panel display.

Set the state to

toONor1to switch the display on. The default is for the

display to be on.

OFFor0

><

value

>

to switch the display o, set the state

8

:DISPlay:ENABle?

Syntax

Description

:DISPlay:ENABle?

The query returns the current state of the display.

A returned value of0indicates that the display is o. A

returned value of1indicates that the display is on.

Example

OUTPUT 728;":DISP:ENAB ON"

8-16 Remote Commands

OUTPUT 728;":DISP:ENAB?"

ENTER 728;A$

:DISPlay:ENABle

Remote Commands 8-17

8

INPut Commands

:INPut:ATTenuation

Syntax

Description

:INPut:ATTenuation<wsp

This command sets the attenuation factor for the instrument.

The attenuation factor is used, with the calibration factor (see

\:INPut:OFFSet") to set the lter attenuation.

Attenuation

You set the attenuation factor by sending a value (default units

are dB), or by sending

minimum, default and maximum values for the attenuation

factor.

The minimum value and the default value are those values for

which

The maximum value is that value for which

at its greatest.

:INPut:ATTenuation?

Syntax

Description

:INPut:ATTenuation?[<

The query returns the current attenuation factor,indB.

Att(dB)=Attenuation

By sending

default or maximum value possible for the attenuation factor is

returned.

lter

Attenuation

MIN,DEF

><

(dB)=

Att(dB)0

MIN,DEForMAX

=0dB.

lter

wsp>MINjDEFjMAX

lter

,or

MAX

with the query the minimum,

value>[DB]jMINjDEFjMAX

Cal(dB

)

, which specify the

Attenuation

]

(dB)+

Cal(dB

)

lter

is

Example

OUTPUT 728;":INP:ATT 32.15"

OUTPUT 728;":INP:ATT?"

8

ENTER 728;A$

8-18 Remote Commands

:INPut:LCMode

:INPut:OFFSet

Syntax

Description

:INPut:LCMode<wsp>OFFjONj0j1

This command sets the function of the wavelength calibration.

That is, whether the wavelength calibration data is to be used

to reposition the lter to keep the attenuation factor constant,

or to alter the attenuation factor with the lter kept in a xed

position.

Switch the mode on (using

value xed, and alter the lter position.

Switch the mode o (usingONor1) to keep the lter position

xed, and alter the attenuation factor.

:INPut:LCMode?

Syntax

Description

:INPut:LCMode?

The query returns the current function of the wavelength

calibration.

0

xed, and altering the lter position.

1

and altering the attenuation factor.

Example

OUTPUT 728;":INP:LCM ON"

OUTPUT 728;":INP:LCM?"

ENTER 728;A$

OFFor0

) to keep the attenuation

indicates that the instrument is keeping the attenuation value

indicates the instrument is keeping the lter position xed,

:INPut:OFFSet

Syntax

Description

:INPut:OFFSet<wsp

This command sets the calibration factor for the instrument.

This factor does not aect the lter attenuation. It is

used to oset the values for the attenuation factor. The

calibration factor is used, with the attenuation factor (see

\:INPut:ATTenuation") to set the attenuation of the lter.

Attenuation

lter

><

value>[DB]jMINjDEFjMAX

(dB)=

Att(dB)0

Cal(dB

8

)

Remote Commands 8-19

:INPut:OFFSet

You set the calibration by sending a value (default units are dB),

or by sending

default and maximum values for the calibration factor.

The minimum value for the calibration factor is -99.999dB.

The default value is 0dB.

The maximum value is 99.999dB.

:INPut:OFFSet?

MIN,DEForMAX

, which specify the minimum,

Syntax

Description

:INPut:OFFSet?[<

The query returns the current calibration factor,indB.

By sending

MIN,DEF

default or maximum value possible for the calibration factor is

returned.

Example

OUTPUT 728;":INP:OFFS 32.15"

OUTPUT 728;":INP:OFFS?"

ENTER 728;A$

:INPut:OFFSet:DISPlay

Syntax

Description

:INPut:OFFSet:DISPlay

This command sets the calibration factor for the instrument

from the current attenuation factor. The lter attenuation is

not aected. The oset is set so that the attenuation factor

becomes zero.

Cal

Example

(dB)=0Att

NEW

OUTPUT 728;":INP:OFFS:DISP"

OUTPUT 728;":INP:OFFS?"

ENTER 728;A$

wsp>MINjDEFjMAX

,or

MAX

with the query the minimum,

lter

(dB)=

Cal

(dB)0Att

OLD

]

(dB)

OLD

8

:INPut:WAVelength

Syntax

Description

:INPut:WAVelength<wsp

><

value>[DB]jMINjDEFjMAX

This command sets the wavelength for the instrument. The

value is used to make the compensation for the wavelength

dependence of the lter, using the wavelength calibration data.

8-20 Remote Commands

:INPut:WAVelength

Note

There are two sets of wavelength calibration data, one is made

in the factory, individually, for your instrument. The other is

left for the you to dene.

Using your own wavelength calibration data, you can use the

attenuator to compensate for the total wavelength dependence

of your hardware conguration.

For more details on this topic

Calibration and Its Function" in Chapter 5.

You set the wavelength by sending a value (default units are

meters), or by sending

minimum, default and maximum values for the wavelength.

The minimum value for the wavelength is 1200nm.

The default value is 1310nm.

The maximum value is 1650nm.

:INPut:WAVelength?

Syntax

Description

:INPut:WAVelength?[<

The query returns the current wavelength, in meters.

By sending

default or maximum value possible for the wavelength is

returned.

MIN,DEF

, see \Selecting the Wavelength

MIN,DEForMAX

wsp>MINjDEFjMAX

,or

MAX

with the query the minimum,

, which specify the

]

Example

OUTPUT 728;":INP:WAV 1550nm"

OUTPUT 728;":INP:WAV?"

ENTER 728;A$

8

Remote Commands 8-21

OUTPut Commands

:OUTPut:APMode

Syntax

Description

Note

:OUTPut:APMode<wsp>OFFjONj0j1

This command sets the whether you set the attenuation factor,

or the through-power to alter the attenuation of the lter.

When you are switching the absolute power modeON, the

attenuation factor (in dB) becomes the base value for the

through-power (in dBm), at the time at which this command is

processed.

That is, if the attenuation factor is set to 32.000dB, and the

absolute power mode is switched on, then the base value for

the through-power is set to 32.000dBm.

Use the calibration factor (see \:INPut:OFFSet") to set the

attenuation factor to the required value for use as the base

value for the through-power

Cal

When you switch the absolute power mode

New

=(

Through0Power

Base

0

Att)+Cal

Current

OFF

, the last set

calibration factor becomes active, and the attenuation factor is

set so that the lter attenuation does not change. That is

Att(dB)=Attenuation

Using any of the

any of the

:INPut:OFFSet

(dB)+

lter

:INPut:ATTenuation

commands or queries, switches the

Cal(dB

)

commands or queries,or

absolute power mode o automatically.

See \:OUTPut:POWer" for information on setting the

through-power.

8

Switch the mode o (using

OFFor0

) to set the attenuation of

the lter by specifying the attenuation and calibration factors.

Switch the mode on (usingONor1) to set the attenuation of the

lter by specifying the through-power.

8-22 Remote Commands

:OUTPut:APMode?

:OUTPut:POWer

Syntax

Description

:OUTPut:APMode?

The query returns whether the attenuation of the lter is

set by the attenuation and calibration factors, or by the

through-power.

0

indicates the instrument sets the attenuation of the lter from

the attenuation and calibration factors.

1

indicates that the instrument sets the attenuation of the lter

from the through-power.

Example

OUTPUT 728;":INP:ATT?"

ENTER 728; Att

OUTPUT 728;":INP:OFFS?"

ENTER 728; Cal

Newcal = Basepow - Att + Cal

OUTPUT 728;":INP:OFFS ";Newcal

OUTPUT 728;":OUTP:APM ON"

OUTPUT 728;":OUTP:APM?"

ENTER 728;A$

:OUTPut:POWer

Syntax

Description

:OUTPut:POWer<wsp

This command sets the through-power for the instrument. The

through-power is used to set the attenuation of the lter.

><

value>[

DBM]j

MINjDEFjMAX

Att

lter

(dB)=

ThroughPower

Base

(

dBm)0

ThroughPower(dBm)+Att

lter@Base

You set the through-power by sending a value (default units

are dBm), or by sending

MIN,DEForMAX

, which specify the

minimum, default and maximum values for the through-power.

The maximum value and the default value are those values for

which

The minimum value is that value for which

Attenuation

lter

=0dB.

Attenuation

lter

its greatest.

For example, if you have set

then switched

INP:APM ON

INP:ATT 10

and

INP:OFFS 2

and

, then the through power is set to

12dBm. The maximum through power, and the default through

power, in this case is 22dBm. The minimum through power in

this case is -38dBm.

Remote Commands 8-23

(dB)

8

is at

:OUTPut:POWer

:OUTPut:POWer?

Syntax

Description

:OUTPut:POWer?[<

The query returns the current through-power, in dBm.

ThroughPower(dBm)=ThroughPower

By sending

MIN,DEF

default or maximum value possible for the through-power is

returned.

Example

OUTPUT 728;":OUTP:POW 32.15"

OUTPUT 728;":OUTP:POW?"

ENTER 728;A$

:OUTPut:[:STATe]

Syntax

Description

:OUTPut[:STATe]<wsp>OFFjONj0j1

This command sets the state of the output shutter, that is,

whether it is open or closed.

OFFor0

ONor1

closes the shutter, and no power gets through.

opens the shutter, and power gets through.

:OUTPut[:STATe]?

Syntax

:OUTPut[:STATe]?

wsp>MINjDEFjMAX

(

dBm)+Att

Base

,or

MAX

with the query the minimum,

]

lter@Base

(dB)0Att

lter

(dB)

Description

Example

The query returns whether the output shutter is open or closed.

0

indicates the shutter is closed (no power is getting through).

1

indicates that the shutter is open (power is getting through).

OUTPUT 728;":OUTP ON"

OUTPUT 728;":OUTP?"

ENTER 728;A$

8

8-24 Remote Commands

:OUTPut:[:STATe]:APOWeron

:OUTPut:[:STATe]:APOWeron

Syntax

Description

:OUTPut[:STATe]:APOWeron?

Syntax

Description

Example

:OUTPut[:STATe]:APOWeron<wsp>DISjLASTj0j1

This command sets the state of the output shutter at power on,

that is, whether it is closed, or takes the state at power-o.

DISor0

through.

LASTor1

:OUTPut[:STATe]:APOWeron?

The query returns whether the output shutter is closed at

power on, or set to the state at power-o.

0

indicates the shutter is closed (no power is getting through).

1

indicates that the shutter is set to the state at power-o.

OUTPUT 728;":OUTP:APOW OFF"

OUTPUT 728;":OUTP:APOW?"

ENTER 728;A$

closes the shutter at power on, and no power gets

sets the shutter to the state at power-o.

Remote Commands 8-25

8

STATus Commands

There are two `nodes' in the status circuitry

The OPERation node indicates things that can happen during normal operation.

The QUEStionable node indicates error conditions

Each node of the status circuitry has ve registers:

A condition register (CONDition), which contains the current status.This

register is updated continuously. It is not changed by having its contents read.

The event register (EVENt), which contains the output from the transition

registers. The contents of this register are cleared when it is read.

A positive transition register (PTRansition), which, when enabled, puts a 1

into the event register, when the corresponding bit in the condition register

goes from 0 to 1.

The power-on condition for this register is for all the bits to be disabled.

A negative transition register (NTRansition), which, when enabled, puts a 1

into the event register, when the corresponding bit in the condition register

goes from 1 to 0.

The power-on condition for this register is for all the bits to be disabled.

The enable register (ENABle), which enables changes in the event register to

aect the Status Byte.

The status registers for the attenuator are organized as shown:

.

.

8

8-26 Remote Commands

:STATus:OPERation:CONDition?

Figure 8-2. The Status Registers

:STATus:OPERation:CONDition?

Syntax

Description

Example

:STATus:OPERation:CONDition?

This query reads the contents of the OPERation:CONDition

register. Only three bits of the condition register are used:

Bit 1, which is 1 when the motor that positions the attenuator

lter is settling.

Bit 3, which is 1 while the instrument is performing an

attenuation sweep.

Bit 7, which is 1 after the instrument has repositioned the

attenuator lter due to a change in temperature.

OUTPUT 728;":STAT:OPER:COND?"

ENTER 728;A$

8

Remote Commands 8-27

:STATus:OPERation:ENABle

Syntax

Description

:STATus:OPERation:ENABle<wsp

This command sets the bits in the ENABle register that

enable the contents of the EVENt register to aect the Status

Byte (STB). Setting a bit in this register to 1 enables the

corresponding bit in the EVENt register to aect bit 7 of the

Status Byte.

:STATus:OPERation:ENABle?

Syntax

Description

:STATus:OPERation:ENABle?

This query returns the current contents of the

OPERation:ENABle register.

Example

OUTPUT 728;":STAT:OPER:ENAB 138"

OUTPUT 728;":STAT:OPER:ENAB?"

ENTER 728;A$

:STATus:OPERation[:EVENt]?

Syntax

Description

:STATus:OPERation[:EVENt]?

This query reads the contents of the OPERation:EVENt register.

Only three bits of the event register are used (whether these

bits contain information depends on the transition register

conguration):

><

value

>

Bit 1, which is 1 when the motor that positions the attenuator

lter is settling.

Bit 3, which is 1 while the instrument is performing an

attenuation sweep.

Bit 7, which is 1 after the instrument has repositioned the

8

Example

attenuator lter due to a change in temperature.

OUTPUT 728;":STAT:OPER?"

ENTER 728;A$

8-28 Remote Commands

:STATus:OPERation:NTRansition

:STATus:OPERation:PTRansition

Syntax

Description

:STATus:OPERation:NTRansition<wsp

This command sets the bits in the NTRansition register. Setting

a bit in this register enables a negative transition (1!0) in the

corresponding bit in the CONDition register to set the bit in the

EVENt register.

:STATus:OPERation:NTRansition?

Syntax

Description

:STATus:OPERation:NTRansition?

This query returns the current contents of the

OPERation:NTRansition register.

Example

OUTPUT 728;":STAT:OPER:NTR 138"

OUTPUT 728;":STAT:OPER:NTR?"

ENTER 728;A$

:STATus:OPERation:PTRansition

Syntax

Description

:STATus:OPERation:PTRansition<wsp

This command sets the bits in the PTRansition register. Setting

a bit in this register enables a positive transition (0!1) in the

corresponding bit in the CONDition register to set the bit in the

EVENt register.

><

><

value

value

>

>

:STATus:OPERation:PTRansition?

Syntax

Description

:STATus:OPERation:PTRansition?

This query returns the current contents of the

OPERation:PTRansition register.

Example

OUTPUT 728;":STAT:OPER:PTR 138"

OUTPUT 728;":STAT:OPER:PTR?"

ENTER 728;A$

8

Remote Commands 8-29

:STATus:QUEStionable:CONDition?

Syntax

Description

:STATus:QUEStionable:CONDition?

This query reads the contents of the QUEStionable:CONDition

register. Only one bit of the condition register is used:

Bit 8, which is 1 when the wavelength is not within the range

of the user wavelength calibration data.

Example

OUTPUT 728;":STAT:QUES:COND?"

ENTER 728;A$

:STATus:QUEStionable:ENABle

Syntax

Description

:STATus:QUEStionable:ENABle<wsp

This command sets the bits in the ENABle register that

enable the contents of the EVENt register to aect the Status

Byte (STB). Setting a bit in this register to 1 enables the

corresponding bit in the EVENt register to aect bit 3 of the

Status Byte.

:STATus:QUEStionable:ENABle?

Syntax

Description

:STATus:QUEStionable:ENABle?

This query returns the current contents of the

QUEStionable:ENABle register.

><

value

>

Example

OUTPUT 728;":STAT:QUES:ENAB 256"

OUTPUT 728;":STAT:QUES:ENAB?"

ENTER 728;A$

:STATus:QUEStionable[:EVENt]?

8

Syntax

Description

:STATus:QUEStionable[:EVENt]?

This query reads the contents of the QUEStionable:EVENt

register. Only one bit of the event register is used (whether

these bits contain information depends on the transition register

conguration):

Bit 8, which is 1 when the wavelength is not within the range

of the user wavelength calibration data.

8-30 Remote Commands

:STATus:QUEStionable:PTRansition

Example

OUTPUT 728;":STAT:QUES 256"

OUTPUT 728;":STAT:QUES?"

ENTER 728;A$

:STATus:QUEStionable:NTRansition

Syntax

Description

:STATus:QUEStionable:NTRansition<wsp

This command sets the bits in the NTRansition register. Setting

a bit in this register enables a negative transition (1!0) in the

corresponding bit in the CONDition register to set the bit in the

EVENt register.

:STATus:QUEStionable:NTRansition?

Syntax

Description

:STATus:QUEStionable:NTRansition?

This query returns the current contents of the

QUEStionable:NTRansition register.

Example

OUTPUT 728;":STAT:QUES:NTR 256"

OUTPUT 728;":STAT:QUES:NTR?"

ENTER 728;A$

:STATus:QUEStionable:PTRansition

><

value

>

Syntax

Description

:STATus:QUEStionable:PTRansition<wsp

This command sets the bits in the PTRansition register. Setting

a bit in this register enables a positive transition (0!1) in the

corresponding bit in the CONDition register to set the bit in the

EVENt register.

:STATus:QUEStionable:PTRansition?

Syntax

Description

:STATus:QUEStionable:PTRansition?

This query returns the current contents of the

QUEStionable:PTRansition register.

Example

OUTPUT 728;":STAT:QUES:PTR 256"

OUTPUT 728;":STAT:QUES:PTR?"

ENTER 728;A$

><

value

>

Remote Commands 8-31

8

:STATus:PRESet

Syntax

Description

Example

:STATus:PRESet

This command presets all the enable registers and transition

lters for both the OPERation and QUEStionable nodes.

All the bits in the ENABle registers are set to 0

All the bits in the PTRansition registers are set to 1

All the bits in the NTRansition registers are set to 0

OUTPUT 728;":STAT:PRES"

8

8-32 Remote Commands

SYSTem Commands

:SYSTem:ERRor?

:SYSTem:ERRor?

Syntax

Description

Example

:SYSTem:ERRor?

This query returns the next error from the error queue (see

\The Error Queue" in Chapter 7). Each error consists of the

error code and a short description of the error, separated by a

comma, for example

in the range -32768 and +32767. Negative error numbers are

dened by the SCPI standard. Positive error numbers are device

dependent. The errors are listed in Appendix G

OUTPUT 728;":SYST:ERR?"

ENTER 728;A$

0, "No error"

. Error codes are numbers

Remote Commands 8-33

8

User Calibration Commands

Entering user calibration data can only be done over the HP-IB

using the commands described here

.

. This is done

Entering the User Calibration Data

To enter the data for the user calibration data, you will need a power meter,a

tunable laser source and the attenuator. If you are going to use the attenuator

to compensate for some other device, this should be included in the setup as

well.

The steps to enter the user calibration data are

1. Set up the hardware.

The following steps can be programmed to make the procedure easy

, as the

calibration values must be entered using the HP-IB anyway.

2. Disable the tunable laser source.

3. Execute a zero on the power meter.

4. Set the attenuation to 0.

5. Set the wavelength on the tunable laser source, the attenuator and the

power meter to the start wavelength.

6. Enable the tunable laser source and the attenuator.

7. Set the power meter to dB, and execute a Display-to-Reference.

8. Set the desired attenuation on the attenuator.

9. Start the user calibration (with the data for the start wavelength and the

wavelength stepsize).

This is done with the

10.=

8

11. Repeat the following steps until



Start

:UCALibration:STARt

>

Stop

.

command

a. Seton the tunable laser source, the attenuator and the power meter.

b. Read the power (

c.

Power=0

d. Set the user calibration value to

Power

Power

.

).

Power

.

8-34 Remote Commands

:UCALibration:STARt

This is done with the

e.=+



Stepsize

12. Stop the user calibration.

This is done with the

:UCALibration:STOP

:UCALibration:STARt

Syntax

Description

:UCALibration:STARt<wsp

This command starts the entering of the user calibration data.

You must send two values with this command, the wavelength

of the rst calibration point, and the spacing between the

calibration points. The default units for both values are meters.

The minimum value for the start wavelength is 1200nm, and the

minimum value for the step size is 0.1nm, the maximum value

for the step size is 10nm.

Other than this, the start and step values must satisfy the

formula

start value

+((

number of step01)2step value)

where the number of steps must be in the range 10 to 401.

The error -221 indicates that there is a conict inherent in

the start parameters for the user calibration. That is, the

start value and/or step value is invalid.

:UCALibration:VALue

command

><

start value>,<step value

command

1650

>

nm

The error 201 indicates that the user calibration is currently

on, and calibration data cannot be changed. Switch the user

calibration state o (see \:UCALibration:STATe") and try again.

:UCALibration:STARt?.

Syntax

Description

:UCALibration:STARt?

The query starts returning the data for the user wavelength

calibration.

Three values are returned in response to this query.

1. The wavelength value for the rst calibration data point (in

meters).

2. The step-size between the data calibration points (in meters).

8

Remote Commands 8-35

:UCALibration:STARt

3. The number of data points that have been stored for the full

calibration.

:UCALibration:STATe

Syntax

Description

:UCALibration:STATe<wsp>OFFjONj0j1

This command selects the wavelength calibration to be used.

The choice is the factory made calibration for the instrument,

or the calibration data entered into the instrument by the user

(see \Selecting the Wavelength Calibration and Its Function"in

Chapter 5).

Switch the state o (using

calibration.

Switch the state on (usingONor1) to use the user calibration

data.

Note

If you are using the instrument in an environment where the

temperature changes, you should not use the user wavelength

calibration data, as it lacks correction for temperature changes

:UCALibration:STATe?.

Syntax

Description

:UCALibration:STATe?

The query returns the current wavelength calibration state.

0

indicates the instrument is using the factory-made wavelength

calibration data.

1

indicates that the instrument is using the user calibration

data.

OFFor0

) to use the factory-made

.

Example

OUTPUT 728;":UCAL:STAT ON"

OUTPUT 728;":UCAL:STAT?"

ENTER 728;A$

8

:UCALibration:STOP

Syntax

Description

:UCALibration:STOP

This command ends the entering of the user calibration data.

The error 203 indicates that entering the data points cannot be

stopped, because it has not been started.

8-36 Remote Commands