Agilent E4418A Programming Guide

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Programming Guide

HP EPM E4418A/E4419A

(EPM-441A/442A)

Power Meters

HP Part no. E4418-90008

January 24, 1997

written permission is prohibited, except as allowed under the copyright laws.

Printed in the UK.

ii HP EPM-441A/442A Programming Guide

Legal Information

Notice

Information contained in this document is subject to change without notice. Hewlett-Packard makes no warranty of any kind with regard to this material, including, but not limited to, the implied warranties of merchantability and ﬁtness for a particular purpose. Hewlett-Packard shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishings, performance, or use of this material. No part of this document may be photocopied, reproduced, or translated to another language without the prior written consent of HP.

Certiﬁcation

Hewlett-Packard Company certiﬁes that this product met its published speciﬁcations at the time of shipment from the factory. Hewlett-Packard further certiﬁes that its calibration measurements are traceable to the United States National Institute of Standards and Technology, to the extent allowed by the Institute’s calibration facility, and to the calibration facilities of other International Standards Organization members.

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, Hewlett-Packard Company will at its option, either repair or replace products which prove to be defective. F or 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, duties, and taxes for products returned to HP from another country. HP warrants that its software and ﬁrmware 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, or ﬁrmware will be uninterrupted or error free.

HP EPM-441A/442A Programming Guide iii

Legal Information

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 modiﬁcation or misuse, operation outside of the environmental speciﬁcations for the product, or improper site preparation or maintenance. NO OTHER WARRANTY IS EXPRESSED OR IMPLIED . HP SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

Exclusive Remedies

THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES. HP SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.

iv HP EPM-441A/442A Programming Guide

Equipment Operation

Warnings and Cautions

This guide uses warnings and cautions to denote hazards.

WARNING A warning calls attention to a procedure, practice or the

like, which, if not correctly performed or adhered to, could result in injury or the loss of life. Do not proceed beyond a warning until the indicated conditions are fully understood and met.

Caution A caution calls attention to a procedure, practice or the like which,

if not correctly performed or adhered to, could result in damage to or the destruction of part or all of the equipment. Do not proceed beyond a caution until the indicated conditions are fully understood and met.

Personal Safety Considerations

WARNING This is a Safety Class I product (provided with a protective

earthing ground incorporated in the power cord). The mains plug shall only be inserted in a socket outlet provided with a protective earth contact. Any interruption of the protective conductor, inside or outside the instrument, is likely to make the instrument dangerous. Intentional interruption is prohibited. If this instrument is not used as speciﬁed, the protection provided by the equipment could be impaired. This instrument must be used in a normal condition (in which all means of protection are intact) only. No operator serviceable parts inside. Refer servicing to qualiﬁed personnel. To prevent electrical shock, do not remove covers. For continued protection against ﬁre hazard, replace the line fuse(s) only with fuses of the same type and rating (for example, normal blow, time delay, etc.). The use of other fuses or material is prohibited.

HP EPM-441A/442A Programming Guide v

General Safety Considerations

WARNING Before this instrument is switched on, make sure it has

been properly grounded through the protective conductor of the ac power cable to a socket outlet provided with protective earth contact. Any interruption of the protective (grounding) conductor, inside or outside the instrument, or disconnection of the protective earth terminal can result in personal injury.

Caution Any adjustments or service procedures that require operation of

the instrument with protective covers removed should be performed only by trained service personnel.

Markings

The CE mark shows that the product complies with all the relevant European legal Directives (if accompanied by a year, it signiﬁes when the design was proven.

GROUP 1

ISM

vi HP EPM-441A/442A Programming Guide

CLASS A

This is the symbol of an Industrial Scientiﬁc and Medical Group 1 Class A product.

The CSA mark is a registered trademark of the Canadian Standards Association.

External Protective Earth Terminal.

While this is a Class I product, provided with a protective earthing conductor in a power cord, an external protective earthing terminal has also been provided. This terminal is for use where the earthing cannot be assured. At least an 18AWG earthing conductor should be used in such an instance, to ground the instrument to an assured earth terminal.

General Safety Considerations

IEC 1010-1 Compliance

This instrument has been designed and tested in accordance with IEC Publication 1010-1 +A1:1992 Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory Use and has been supplied in a safe condition. The instruction documentation contains information and warnings which must be followed by the user to ensure safe operation and to maintain the instrument in a safe condition.

HP EPM-441A/442A Programming Guide vii

About this Guide

Chapter 1: Power Meter Remote Operation

This chapter describes the parameters which conﬁgure the power meter

and help you determine settings to optimize performance.

Chapter 2: Application Programs

This chapter provides several remote interface application programs to aid you in developing measurement programs.

Chapter 3: SCPI Command Reference

This chapter provides reference information to help you program the power meter over the remote interface using SCPI (Standard Commands for Programmable Instruments).

Chapter 4: Alternate Programming Language

This chapter provides information on how you can conﬁgure the HP EPM441A/442A Power Meter to accept and execute the commands of either the HP 437B Power Meter or the HP 438A Power Meter.

Chapter 6: IEEE488.2 Command Reference

This chapter contains information about the IEEE 488.2 Common (*) Commands that the power meter supports.

viii HP EPM-441A/442A Programming Guide

List of Related Publications

The HP EPM-441A User’s Guide and the HP EPM-442A User’s Guide are available in the following languages:

• English Language User’s Guide - Standard

• German Language User’s Guide - Option ABD

• Spanish Language User’s Guide - Option ABE

• French Language User’s Guide - Option ABF

• Italian Language User’s Guide - Option ABZ

• Japanese Language User’s Guide - Option ABJ

HP EPM-441A/442A Service Guide is available by ordering Option 915. HP 440A/442A CLIPs (Component Location and Information Pack) is

available by ordering E4418-90007. Useful information on SCPI (Standard Commands for Programmable

Instruments) can be found in:

• A Beginner’s Guide to SCPI, which is available by ordering HP Part Number 5010-7166.

• The SCPI reference manuals which are available from: SCPI Consortium, 8380 Hercules Drive, Suite P3, La Mesa, CA 91942, USA. Telephone: 619-697-4301 Fax: 619-697-5955

HP EPM-441A/442A Programming Guide ix

List of Related Publications

x HP EPM-441A/442A Programming Guide

Table of Contents

Page

Legal Information ........................................................................iii

Notice .....................................................................................iii

Certification...........................................................................iii

Warranty................................................................................iii

Limitation of Warranty......................................................... iv

Exclusive Remedies............................................................... iv

Equipment Operation................................................................... v

Personal Safety Considerations............................................. v

General Safety Considerations.................................................... vi

Markings................................................................................ vi

IEC 1010-1 Compliance........................................................ vii

About this Guide........................................................................viii

List of Related Publications ........................................................ ix

Power Meter Remote Operation...................................................... 1-1

Introduction................................................................................... 1-2

Configuring the Remote Interface................................................ 1-3

HP-IB Address........................................................................ 1-3

Programming Language Selection (HP EPM-441A only) .... 1-4

Zeroing and Calibrating the Power Meter................................... 1-8

Zeroing .................................................................................... 1-8

Calibration.............................................................................. 1-8

Setting the Reference Calibration Factor ............................. 1-10

Making Measurements................................................................. 1-11

Using MEASure?.................................................................... 1-12

Using the CONFigure Command .......................................... 1-17

Using the Lower Level Commands........................................ 1-26

Using Sensor Calibration Tables ................................................. 1-27

Overview................................................................................. 1-27

Editing Sensor Calibration Tables ........................................ 1-30

Selecting a Sensor Calibration Table.................................... 1-35

Enabling the Sensor Calibration Table System.................... 1-35

Making the Measurement...................................................... 1-36

Setting the Range, Resolution and Averaging ............................ 1-37

Range....................................................................................... 1-37

Resolution ...............................................................................1-38

HP EPM-440A/442A User’s Guide Contents-1

Averaging................................................................................ 1-38

Setting Offsets............................................................................... 1-41

Channel Offsets...................................................................... 1-41

Display Offsets........................................................................ 1-41

Example .................................................................................. 1-42

Setting Measurement Limits ....................................................... 1-43

Checking for Limit Failures................................................... 1-44

Measuring Pulsed Signals............................................................ 1-46

Making the Measurement...................................................... 1-46

Triggering the Power Meter......................................................... 1-49

Idle State................................................................................. 1-51

Initiate State........................................................................... 1-52

Event Detection State ............................................................ 1-52

Trigger Delay.......................................................................... 1-53

Getting the Best Speed Performance.......................................... 1-54

Speed....................................................................................... 1-54

Trigger Mode........................................................................... 1-54

Output Format........................................................................ 1-56

Units........................................................................................ 1-56

Command Used ...................................................................... 1-56

200 Readings/Sec.................................................................... 1-56

Dual Channel Considerations................................................ 1-57

How Measurements are Calculated............................................. 1-58

Status Reporting........................................................................... 1-59

The General Status Register Model...................................... 1-60

How to Use Registers............................................................. 1-62

Status Register....................................................................... 1-68

Using the Operation Complete Commands .......................... 1-78

Saving and Recalling Power Meter Configurations.................... 1-80

How to Save and Recall a Configuration............................... 1-80

Example Program................................................................... 1-80

Using Device Clear to Halt Measurements................................. 1-81

An Introduction to the SCPI Language....................................... 1-82

Syntax Conventions................................................................ 1-84

SCPI Data Types.................................................................... 1-84

Input Message Terminators................................................... 1-90

Quick Reference............................................................................ 1-91

MEASurement Commands.................................................... 1-92

CALCulate Subsystem........................................................... 1-93

CALibration Subsystem......................................................... 1-93

DISPlay Subsystem................................................................ 1-94

FORMat Subsystem ............................................................... 1-94

MEMory Subsystem............................................................... 1-95

Contents-2 HP EPM-440A/442A User’s Guide

OUTPut Subsystem................................................................ 1-95

[SENSe] Subsystem................................................................ 1-96

STATus Subsystem ................................................................ 1-97

SYSTem Subsystem ............................................................... 1-98

TRIGger Subsystem ...............................................................1-98

UNIT Subsystem.................................................................... 1-98

SCPI Compliance Information ..................................................... 1-99

MEASurement Instructions.............................................................. 2-1

MEASurement Instructions......................................................... 2-2

CONFigure[1|2]?.......................................................................... 2-6

CONFigure[1|2] Commands........................................................ 2-8

CONFigure[1|2][:SCALar][:POWer:AC] [<expected_value>

[,<resolution>[,<source list>]]]..................................................... 2-9

CONFigure[1|2][:SCALar][:POWer:AC]:RELative

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-11

CONFigure[1|2][:SCALar][:POWer:AC]:DIFFerence

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-13

CONFigure[1|2][:SCALar][:POWer:AC]:DIFFerence:RELative

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-15

CONFigure[1|2][:SCALar][:POWer:AC]:RATio

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-17

CONFigure[1|2][:SCALar][:POWer:AC]:RATio:RELative

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-19

FETCh[1|2] Queries..................................................................... 2-21

FETCh[1|2][:SCALar][:POWer:AC]? [<expected_value>

[,<resolution>[,<source list>]]]..................................................... 2-22

FETCh[1|2][:SCALar][:POWer:AC]:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-24

FETCh[1|2][:SCALar][:POWer:AC]:DIFFerence?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-27

FETCh[1|2][:SCALar][:POWer:AC]:DIFFerence:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-29

FETCh[1|2][:SCALar][:POWer:AC]:RATio?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-31

FETCh[1|2][:SCALar][:POWer:AC]:RATio:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-33

READ[1|2] Commands................................................................. 2-35

READ[1|2][:SCALar][:POWer:AC]? [<expected_value>

[,<resolution>[,<source list>]]]..................................................... 2-36

READ[1|2][:SCALar][:POWer:AC]:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-38

HP EPM-440A/442A User’s Guide Contents-3

READ[1|2][:SCALar][:POWer:AC]:DIFFerence?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-41

READ[1|2][:SCALar][:POWer:AC]:DIFFerence:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-43

READ[1|2][:SCALar][:POWer:AC]:RATio? [<expected_value>

[,<resolution>[,<source list>]]]..................................................... 2-45

READ[1|2][:SCALar][:POWer:AC]:RATio:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-47

MEASure[1|2] Commands........................................................... 2-49

MEASure[1|2][:SCALar][:POWer:AC]? [<expected_value>

[,<resolution>[,<source list>]]]..................................................... 2-50

MEASure[1|2][:SCALar][:POWer:AC]:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-52

MEASure[1|2][:SCALar][:POWer:AC]:DIFFerence?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-54

MEASure[1|2][:SCALar][:POWer:AC]:DIFFerence:RELative?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-56

MEASure[1|2][:SCALar][:POWer:AC]:RATio?

[<expected_value>[,<resolution>[,<source list>]]]...................... 2-58

MEASure[1|2][:SCALar][:POWer:AC]:RATio:RELa-

tive?[<expected_value>[,<resolution>[,<source list>]]] .............. 2-60

CALCulate Subsystem........................................................................ 3-1

CALCulate Subsystem.................................................................. 3-2

The CALCulate[1|2]:GAIN Node ................................................ 3-3

CALCulate[1|2]:GAIN[:MAGNitude] <numeric_value>............ 3-4

CALCulate[1|2]:GAIN:STATe <Boolean>.................................. 3-6

The CALCulate[1|2]:MATH Node............................................... 3-7

CALCulate[1|2]:MATH[:EXPRession] <string>......................... 3-8

CALCulate[1|2]:MATH[:EXPRession]:CATalog?....................... 3-10

The CALCulate[1|2]:RELative Node .......................................... 3-11

CALCulate[1|2]:RELative[:MAGNitude]:AUO<Boolean>

|ONCE .......................................................................................... 3-12

CALCulate[1|2]:RELative:STATe <Boolean>............................ 3-14

CALibration Subsystem..................................................................... 4-1

CALibration Subsystem ............................................................... 4-2

CALibration[1|2][:ALL]............................................................... 4-3

CALibration[1|2][:ALL]?.............................................................. 4-5

CALibration[1|2]:AUTO <Boolean>|ONCE............................... 4-7

CALibration[1|2]:RCFactor <numeric_value>........................... 4-9

CALibration[1|2]:ZERO:AUTO <Boolean>|ONCE ................... 4-11

Contents-4 HP EPM-440A/442A User’s Guide

DISPlay Subsystem............................................................................. 5-1

DISPlay Subsystem ...................................................................... 5-2

DISPlay:CONTrast <numeric_value>......................................... 5-3

DISPlay:ENABle <Boolean>........................................................ 5-5

DISPlay[:WINDow[1|2]] Node..................................................... 5-6

DISPlay[:WINDow[1|2]]:FORMat <character_data>................ 5-7

DISPlay[:WINDow[1|2]]:METer Node........................................ 5-9

DISPlay[:WINDow[1|2]]:METer:LOWer <numeric_value> ...... 5-10

DISPlay[:WINDow[1|2]]:METer:UPPer <numeric_value> ....... 5-12

DISPlay[:WINDow[1|2]]:RESolution <numeric_value>............ 5-14

DISPlay[:WINDow[1|2]]:SELect................................................. 5-16

DISPlay[:WINDow[1|2]][:STATe] <Boolean>............................. 5-17

FORMat Subsystem ............................................................................ 6-1

FORMat Subsystem...................................................................... 6-2

FORMat[:READings]:BORDer NORMal|SWAPped.................. 6-3

FORMat[:READings][:DATA] <Type>......................................... 6-4

MEMory Subsystem............................................................................ 7-1

MEMory Subsystem...................................................................... 7-2

MEMory:CATalog Node................................................................ 7-3

MEMory:CATalog[:ALL]?............................................................. 7-4

MEMory:CATalog:STATe? ........................................................... 7-6

MEMory:CATalog:TABLe?........................................................... 7-7

MEMory:CLEar Node................................................................... 7-9

MEMory:CLEar[:NAME] <string> .............................................. 7-10

MEMory:CLEar:TABLe................................................................ 7-11

The MEMory:FREE Node............................................................. 7-12

MEMory:FREE[:ALL]?................................................................. 7-13

MEMory:FREE:STATe?................................................................ 7-14

MEMory:FREE:TABLe?............................................................... 7-15

MEMory:NSTates?........................................................................ 7-16

The MEMory:STATe Node ........................................................... 7-17

MEMory:STATe:CATalog? ........................................................... 7-18

MEMory:STATe:DEFine <string>,<numeric_value>................. 7-19

MEMory:TABLe Node .................................................................. 7-21

MEMory:TABLe:FREQuency <numeric_value>

{,<numeric_value>}....................................................................... 7-22

MEMory:TABLe:FREQuency:POINts?........................................ 7-25

MEMory:TABLe:GAIN[:MAGNitude]

<numeric_value>{,<numeric_value>}.......................................... 7-26

MEMory:TABLe:GAIN[:MAGNitude]:POINts?.......................... 7-28

MEMory:TABLe:MOVE <string>,<string>................................. 7-29

MEMory:TABLe:SELect <string>................................................ 7-30

HP EPM-440A/442A User’s Guide Contents-5

OUTput Subsystem............................................................................. 8-1

OUTPut Subsystem...................................................................... 8-2

OUTPut:ROSCillator[:STATe] <Boolean> .................................. 8-3

SENSe Subsystem................................................................................ 9-1

[SENSe] Subsystem...................................................................... 9-2

[SENSe[1]]|SENSe2:AVERage Node.......................................... 9-4

[SENSe[1]]|SENSe2:AVERage:COUNt <numeric_value>........ 9-5

[SENSe[1]]|SENSe2:AVERage:COUNt:AUTO <Boolean>

|ONCE .......................................................................................... 9-7

[SENSe[1]]|SENSe2:AVERage[:STATe] <Boolean>.................. 9-10

[SENSe[1]]|SENSe2:CORRection Node...................................... 9-11

[SENSe[1]]|SENSe2:CORRection:CSET Node........................... 9-12

[SENSe[1]]|SENSe2:CORRection:CSET[:SELect] <string>...... 9-13

[SENSe[1]]|SENSe2:CORRection:CSET:STATe <Boolean>..... 9-15

[SENSe[1]]|SENSe2:CORRection:DCYCle|GAIN3 Node......... 9-17

[SENSe[1]]|SENSe2:CORRection:DCYCle|GAIN3[:INPut]

[:MAGNitude] <numeric_value>.................................................. 9-18

[SENSe[1]]|SENSe2:CORRection:DCYCle|GAIN3:STATe

<Boolean>...................................................................................... 9-21

[SENSe[1]]|SENSe2:CORRection:GAIN[1|2] Node .................. 9-23

[SENSe[1]]|SENSe2:CORRection:CFACtor|GAIN[1|2]

[:INPut][:MAGNitude] <numeric_value>.................................... 9-24

[SENSe[1]]|SENSe2:CORRection:GAIN2:STATe <Boolean> ... 9-27

[SENSe[1]]|SENSe2:CORRection:LOSS2 Node......................... 9-29

[SENSe[1]]|SENSe2:CORRection:LOSS2[:INPut]

[:MAGNitude] <numeric_value>.................................................. 9-30

[SENSe[1]]|SENSe2:CORRection:LOSS2:STATe <Boolean> ... 9-32 [SENSe[1]]|SENSe2:FREQuency[:CW|:FIXed]

<numeric_value>........................................................................... 9-34

The [SENSe[1]]|SENSe2:LIMit:CLEar Node............................. 9-36

[SENSe[1]]|SENSe2:LIMit:CLEar:AUTO <Boolean>

|ONCE .......................................................................................... 9-37

[SENSe[1]]|SENSe2:LIMit:CLEar[:IMMediate]........................ 9-39

[SENSe[1]]|SENSe2:LIMit:FAIL?............................................... 9-40

[SENSe[1]]|SENSe2:LIMit:FCOunt?.......................................... 9-41

[SENSe[1]]|SENSe2:LIMit:LOWer[:DATA] <numeric_value>. 9-43

[SENSe[1]]|SENSe2:LIMit:STATe <Boolean>........................... 9-45

[SENSe[1]]|SENSe2:LIMit:UPPer[:DATA] <numeric_value>.. 9-46

[SENSe[1]]|SENSe2:POWer:AC:RANGe <numeric_value>...... 9-48

[SENSe[1]]|SENSe2:POWer:AC:RANGe:AUTO <Boolean> ..... 9-49

[SENSe[1]]|SENSe2:SPEed <numeric_value>........................... 9-51

Contents-6 HP EPM-440A/442A User’s Guide

STATus Subsystem............................................................................ 10-1

STATus Subsystem..................................................................... 10-2

Status Register Set Commands ................................................. 10-4

Device Status Register Sets ....................................................... 10-8

Operation Register Sets.............................................................. 10-10

STATus:OPERation.................................................................... 10-11

STATus:OPERation:CALibrating[:SUMMary]......................... 10-12

STATus:OPERation:LLFail[:SUMMary]................................... 10-13

STATus:OPERation:MEASuring[:SUMMary].......................... 10-14

STATus:OPERation:SENSe[:SUMMary] .................................. 10-15

STATus:OPERation:TRIGger[:SUMMary]................................ 10-16

STATus:OPERation:ULFail[:SUMMary].................................. 10-17

STATus:PRESet.......................................................................... 10-18

Questionable Register Sets......................................................... 10-19

STATus:QUEStionable............................................................... 10-20

STATus:QUEStionable:CALibration[:SUMMary].................... 10-21

STATus:QUEStionable:POWer[:SUMMary]............................. 10-22

SYSTem Subsystem........................................................................... 11-1

SYSTem Subsystem.................................................................... 11-2

SYSTem:COMMunicate:GPIB[:SELF]:ADDRess

<numeric_value>......................................................................... 11-3

SYSTem:ERRor? ......................................................................... 11-4

SYSTem:LANGuage <character_data>..................................... 11-5

SYSTem:PRESet......................................................................... 11-6

SYSTem:VERSion? ..................................................................... 11-9

TRIGger Subsystem.......................................................................... 12-1

TRIGger Subsystem.................................................................... 12-2

ABORt[1|2]................................................................................. 12-3

INITiate Node .............................................................................12-4

INITiate[1|2]:CONTinuous <Boolean>..................................... 12-5

INITiate[1|2][:IMMediate]......................................................... 12-7

TRIGger Node .............................................................................12-8

TRIGger[1|2]:DELay:AUTO <Boolean>................................... 12-9

TRIGger[1|2][:IMMediate]......................................................... 12-11

TRIGger[1|2]:SOURce BUS|IMMediate|HOLD..................... 12-12

UNIT Subsystem................................................................................ 13-1

UNIT Subsystem......................................................................... 13-2

UNIT[1|2]:POWer <amplitude_unit>....................................... 13-3

UNIT[1|2]:POWer:RATio <ratio_unit>..................................... 13-6

HP EPM-440A/442A User’s Guide Contents-7

IEEE488.2 Command Reference.................................................... 14-1

IEEE-488 Compliance Information............................................ 14-2

Universal Commands ................................................................. 14-3

DCL....................................................................................... 14-3

GET....................................................................................... 14-3

GTL ....................................................................................... 14-3

LLO ....................................................................................... 14-4

PPC........................................................................................ 14-4

PPD ....................................................................................... 14-4

PPE........................................................................................ 14-4

PPU....................................................................................... 14-5

SDC ....................................................................................... 14-5

SPD........................................................................................ 14-6

SPE........................................................................................ 14-6

*CLS ............................................................................................ 14-7

*DDT <arbitrary block program data>|<string program

data>............................................................................................ 14-8

*ESE <NRf>................................................................................ 14-10

*ESR?........................................................................................... 14-11

*IDN?........................................................................................... 14-12

*OPC............................................................................................ 14-13

*OPT? .......................................................................................... 14-14

*RCL <NRf>................................................................................ 14-15

*RST ............................................................................................ 14-16

*SAV <NRf>................................................................................ 14-17

*SRE <NRf>................................................................................ 14-18

*STB?........................................................................................... 14-20

*TRG............................................................................................ 14-22

*TST?........................................................................................... 14-23

*WAI............................................................................................ 14-24

Contents-8 HP EPM-440A/442A User’s Guide

HP EPM-440A/442A User’s Guide Contents-9

List of Figures

Page

1-1 Sensor Calibration Tables......................................................... 1-28

1-2 Averaged Readings.................................................................... 1-39

1-3 Averaging Range Hysteresis..................................................... 1-39

1-4 Limits Checking Application..................................................... 1-43

1-5 Limits Checking Results ...........................................................1-43

1-6 Pulsed Signal ............................................................................. 1-46

1-7 Trigger System........................................................................... 1-51

1-8 How Measurements are Calculated.......................................... 1-58

1-9 Generalized Status Register Model.......................................... 1-60

1-10 Typical Status Register Bit Changes........................................ 1-61

1-11 Status System............................................................................ 1-68

3-1 CALCulate Block .......................................................................3-2

9-1 Averaged Readings.................................................................... 9-7

HP EPM-440A/442A User’s Guide Contents-10

List of Tables

Page

1-1 HP 437B Command Summary.................................................. 1-5

1-2 MEASure? and CONFigure Preset States ............................... 1-11

1-3 Bit Definitions - Status Byte Register...................................... 1-69

1-4 Bit Definitions - Standard Event Register............................... 1-71

5-1 Measurement Units................................................................... 5-10

5-2 Measurement Units................................................................... 5-12

10-1 Status Data Structure............................................................. 10-2

11-1 Preset Settings......................................................................... 11-6

14-1 PPD Mapping........................................................................... 14-4

14-2 PPE Mapping........................................................................... 14-5

14-3 *ESE Mapping......................................................................... 14-10

14-4 *ESR? Mapping........................................................................ 14-11

14-5 *SRE Mapping......................................................................... 14-18

14-6 *STB? Mapping........................................................................ 14-20

HP EPM-440A/442A User’s Guide Contents-11

Contents-12 HP EPM-440A/442A User’s Guide

Power Meter Remote Operation

Introduction

This chapter describes the parameters which conﬁgure the power meter and help you determine settings to optimize performance. It contains the following sections:

“Conﬁguring the Remote Interface”, on page 1-3. “Zeroing and Calibrating the Power Meter”, on page 1-8. “Making Measurements”, on page 1-11. “Using Sensor Calibration Tables”, on page 1-27. “Setting the Range, Resolution and Averaging”, on page 1-37. “Setting Offsets”, on page 1-41. “Setting Measurement Limits”, on page 1-43. “Measuring Pulsed Signals”, on page 1-46. “Triggering the Power Meter”, on page 1-49. “Getting the Best Speed Performance”, on page 1-54. “How Measurements are Calculated”, on page 1-58. “Status Reporting”, on page 1-59. “Saving and Recalling Power Meter Conﬁgurations”, on page 1-80. “Using Device Clear to Halt Measurements”, on page 1-81. “An Introduction to the SCPI Language”, on page 1-82. “Quick Reference”, on page 1-91. “SCPI Compliance Information”, on page 1-99.

1-2 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Configuring the Remote Interface

Conﬁguring the Remote Interface

This section describes how to conﬁgure the remote interface.

HP-IB Address

Each device on the HP-IB (IEEE-488) interface must have a unique address. You can set the power meter’s address to any value between 0 and 30. The address is set to 13 when the power meter is shipped from the factory.

The address is stored in non-volatile memory, and does not change when the power meter is switched off, or after a remote interface reset.

Your HP-IB bus controller has its own address. Avoid using the bus controller’s address for any instrument on the interface bus. Hewlett-Packard controllers generally use address 21.

To set the HP-IB address from the front panel:

1. Press , . The current HP-IB address is displayed on the softkey.

System Inputs

HP-IB Addr

2. To change this setting press . The power meter displays the address in a pop up window on the measurement screen. Modify this address (see below) as desired.

■ Use or to modify the digit on which the cursor is

currently positioned.

■ Use or to move to other digits.

3. To conﬁrm your choice press .

HP-IB

HP-IB Addr

Enter

To set the HP-IB address from the remote interface use the:

• SYSTem:COMMunicate:GPIB:ADDRess command.

To query the HP-IB address from the remote interface use the;

• SYSTem:COMMunicate:GPIB:ADDRess? query.

HP EPM-441A/442A Programming Guide 1-3

Power Meter Remote Operation

Configuring the Remote Interface

Programming Language Selection (HP EPM-441A only)

You can select one of two languages to program the power meter from the remote interface. The language is SCPI when the power meter is shipped from the factory. The other language is the HP 437B programming language.

The language selection is stored in non-volatile memory, and does not change when power has been off or after a remote interface reset.

To select the interface language from the front panel:

1. Press , , .

System Inputs

2. Select the language you require from and .

To select the interface language from the remote interface use the:

• SYSTem:LANGuage command.

To query the interface language from the remote interface use the:

• SYSTem:LANGuage? query.

HP-IB Command Set

HP 437B SCPI

Table 1-1 details all the HP 437B commands that the HP EPM-441A supports and their function. For a detailed description of these commands refer to the HP 437B Power Meter Operating Manual. In addition the SYST:LANG SCPI command allows you to return to using the SCPI programming language when in the HP 437B mode.

1-4 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Configuring the Remote Interface

Table 1-1: HP 437B Command Summary

Command Description

*CLS

CS CT

DC0 DC1

Calibrate Clear all status registers Clear the status byte Clear sensor table All display segments on

Duty Cycle off Duty Cycle on

DD Display disable DE Display enable DF

DY EN

ERR?

*ESR?

*ESE

*ESE?

ET EX FA FH FM

FR GT0 GT1 GT2

*IDN?

Display enable Down arrow key

Display user message Enter duty cycle

Enter Device error query Event status register query Set event status register mask Event status register mask query Edit sensor table Exit Automatic ﬁlter selection Filter hold Manual ﬁlter selection Enter measurement frequency Ignore GET bus command Trigger immediate response to GET Trigger with delay response to GET Gigahertz Hertz Identiﬁcation query Identiﬁcation query Enter measurement cal factor

HP EPM-441A/442A Programming Guide 1-5

Power Meter Remote Operation

Configuring the Remote Interface

Command Description

KZ LG LH

LL LM0 LM1

LN LP2

MZ OC0 OC1

OD OF0 OF1

OS PCT

RH RL0 RL1 RL2

*RST

Kilohertz Log units (dBm/dB) Enter high (upper) limit Enter low (lower) limit Disable limits checking Enable limits checking Linear units (watts/%) Learn mode Left arrow key

Megahertz Reference oscillator off Reference oscillator on Output display Offset off Offset on Enter offset value Percent Preset Auto range Recall instrument conﬁguration Set display resolution Enter sensor table reference calibration factor Range hold Exit from relative mode Enter relative mode (take new reference) Enter relative mode (use last reference) Set measurement range Reset Right arrow key

Read service request mask Select sensor calibration table Status message Enter sensor identiﬁcation/serial number

1-6 HP EPM-441A/442A Programming Guide

Configuring the Remote Interface

Command Description

SPD 20|40

*SRE

*SRE?

*STB?

SYST:LANG SCPI

TR0 TR1 TR2 TR3

*TST?

ZE @1 @2

Special

Set the service request mask Service request mask query Store (save) power meter conﬁguration Read status byte

Selects SCPI language Trigger hold

Trigger immediate Trigger with delay Trigger free run Self test query Up arrow key

Zero Preﬁx for status mask Learn mode preﬁx Percent

Power Meter Remote Operation

1. This command is accepted but has no active function.

2. This command is not an original HP 437B command. However , it can be used to set the measurement speed to 20 or 40 readings/sec in HP 437B mode. See SENSE:SPEED for more details.

3. This command is not an original HP 437B command. However , it can be used to terminate the HP 437B language and select the SCPI language. Note that it is recommended that the instrument is Preset following a language switch.

4. Always returns 0000 in HP 437B language.

HP EPM-441A/442A Programming Guide 1-7

Power Meter Remote Operation

Zeroing and Calibrating the Power Meter

This section describes how to zero and calibrate the power meter. The calibration and zeroing commands are overlapped commands refer to

“Using the Operation Complete Commands”, on page 1-78 to determine when the commands are complete.

Zeroing

Zeroing adjusts the power meter’s speciﬁed channel for a zero power reading with no power applied to the power sensor.

The command used to zero the power meter is:

CALibration[1|2]:ZERO:AUTO ONCE

The command assumes that there is no power being applied to the sensor. It turns the power reference oscillator off, then after zeroing, returns the power reference oscillator to the same state it was in prior to the command being received. Zeroing takes approximately 10 seconds depending on the type of power sensor being used.

When to Zero?

Zeroing of the power meter is recommended:

• when a 50C change in temperature occurs.

• when you change the power sensor.

• every 24 hours.

• prior to measuring low level signals. F or example , 10 dB above the lowest speciﬁed power for your power sensor.

Calibration

Calibration sets the gain of the power meter using a 50 MHz 1 mW calibrator as a traceable power reference. The power meter’s POWER REF output or a suitable external reference is used as the signal source for calibration. An essential part of calibrating is setting the correct reference calibration factor for the power sensor you are using. The HP 8480 series power sensors require you to set the reference calibration factor. The HP E-series power sensors set the reference calibration factor

1-8 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Zeroing and Calibrating the Power Meter

automatically. Offset, relative and duty cycle settings are ignored during calibration.

The command used to calibrate the power meter is:

CALibration[1|2]:AUTO ONCE

The command assumes that the power sensor is connected to a 1 mW reference signal. It turns the power reference oscillator on, then after calibrating, returns the power reference oscillator to the same state it was in prior to the command being received. It is recommended that you zero the power meter before calibrating.

Calibration Sequence

This feature allows you to perform a complete calibration sequence with a single query. The query is:

CALibration[1|2][:ALL]?

The query assumes that the power sensor is connected to the power reference oscillator. It turns the power reference oscillator on, then after calibrating, returns the power reference oscillator to the same state it was in prior to the command being received. The calibration sequence consists of:

• Zeroing the power meter (CALibration[1|2]:ZERO:AUTO ONCE), and

• calibrating the power meter (CALibration[1|2]:AUTO ONCE).

The query enters a number into the output buffer when the sequence is complete. If the result is 0 the sequence was successful. If the result is 1 the sequence failed. Refer to “CALibration[1|2][:ALL]?”, on page 4-5 for further information.

Note The CALibration[1|2][:ALL] command is identical to the

CALibration[1|2][:ALL]? query except that no number is

returned to indicate the outcome of the sequence. You can examine the Questionable Status Register or the error queue to discover if the sequence has passed or failed. Refer to “Status Reporting”, on page 1-59 for further information.

HP EPM-441A/442A Programming Guide 1-9

Power Meter Remote Operation

Zeroing and Calibrating the Power Meter

Setting the Reference Calibration Factor

All the HP 8480 series power sensors require you to set the reference calibration factor. The reference calibration factor can be set by:

• entering the value into the power meter using the CALibrate[1|2]:RCFactor command.

• selecting and enabling the sensor calibration table. The reference calibration factor is automatically set by the power meter using the reference calibration factor stored in the sensor calibration table. See “Using Sensor Calibration Tables”, on page 1-27 for further information.

Examples

a) To enter a reference calibration factor of 98.7% for channel A, you

should use the following command :

CAL:RCF 98.7PCT

This overides any RCF previously set by selecting a sensor calibration table.

b) To automatically set the reference calibration factor, you have to

use a sensor calibration table as described in “Using Sensor Calibration Tables”, on page 1-27. To select and enable the table d use the following commands:

[SENSe[1]]|SENSe2:CORRection:CSET:SELect <string> [SENSe[1]]|SENSe2:CORRection:CSET:STATe ON

When the sensor calibration table is selected the RCF from the table overides any value previously set.

Querying the Reference Calibration Factor

To determine the current reference calibration factor, use the following command:

CALibration[1|2]:RCFactor?

1-10 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Making Measurements

The MEASure? and CONFigure commands provide the most straight-forward method to program the power meter for measurements. You can select the measurement’s expected power level, resolution and with the HP EPM-442A the measurement type (that is single channel, difference or ratio measurements) all in one command. The power meter automatically presets other measurement parameters to default values as shown in Table 1-2.

Table 1-2: MEASure? and CONFigure Preset States

Command

Trigger source (TRIGger:SOURce)

Filter (SENSe:AVERage:COUNt:AUTO)

Filter state (SENSe:AVERage:STATe)

Trigger cycle (INITiate:CONTinuous)

Trigger Delay (TRIGger:DELay:AUTO)

An alternative method to program the power meter is to use the lower level commands. The advantage of using the lower level commands over the CONFigure command is that they give you more precise control of the power meter. As shown in Table 1-2 the CONFigure command presets various states in the power meter. It may be likely that you do not want to preset these states. Refer to “Using the Lower Level Commands”, on page 1-26 for further information.

MEASure? and CONFigure

Setting

Immediate

Off

HP EPM-441A/442A Programming Guide 1-11

Power Meter Remote Operation

Making Measurements

Using MEASure?

The simplest way to program the power meter for measurements is by using the MEASure? query. However, this command does not offer much ﬂexibility. When you execute the command, the power meter selects the best settings for the requested conﬁguration and immediately performs the measurement. You cannot change any settings (other than the expected power value, resolution and with the HP EPM-442A the measurement type) before the measurement is taken. This means you cannot ﬁne tune the measurement, for example, you cannot change the ﬁlter length. To make more ﬂexible and accurate measurements use the CONFIGure command. The measurement results are sent to the output buffer. MEASure? is a compound command which is equivalent to an ABORT, followed by a CONFigure, followed by a READ?.

MEASure? Examples

The following commands show a few examples of how to use the MEASure? query to make a measurement. It is advisable to read through these examples in order as they become increasingly more detailed. These examples conﬁgure the power meter for a measurement (as described in each individual example), automatically place the power meter in the “wait-for-trigger” state, internally trigger the power meter to take one reading, and then sends the reading to the output buffer.

These examples give an overview of the MEASure? query. For further information on the MEASure? commands refer to the section “MEASure[1|2] Commands” starting on page 2-49 .

Example 1 - The Simplest Method

The following commands show the simplest method of making single channel (for example A or B) measurements. Using MEAS1? will result in an upper window measurement, and MEAS2? in a lower window measurement. The channel associated with the window can be set using the source list parameter (see example 2), or will default as in this example (See “HP EPM-442A only” on page 15.).

speciﬁes window

MEAS1? MEAS2?

1-12 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Making Measurements

Example 2 - Specifying the Source List Parameter

The MEASure command has three optional parameters, an expected power value, a resolution and a source list. These parameters must be entered in the speciﬁed order. If parameters are omitted, they will default from the right. The parameter DEFault is used as a place holder.

The following example uses the source list parameter to specify the measurement channel as channel A. The expected power and resolution parameters are defaulted, leaving them at their current settings. The measurement is carried out on the upper window.

speciﬁes window speciﬁes channel

MEAS1? DEF,DEF,(@1)

The operation of the MEAS1? command when the source list parameter is defaulted is described in the note on page 1-15.

Note For the HP EPM-441A it is not necessary to specify a channel as

only one channel is available.

Example 3 - Specifying the Expected Power Parameter

The previous example details the three optional parameters which can be used with the MEASure? command. The ﬁrst optional parameter is used to enter an expected power value. Entering this parameter is only relevant if you are using an HP E-series power sensor. The value entered determines which of the power sensor’s two ranges is used for the measurement. If the current setting of the power sensor’s range is no longer valid for the new measurement, specifying the expected power value decreases the time taken to obtain a result.

The following example uses the expected value parameter to specify a value of -50 dBm. This selects the power sensor’s lower range (refer to “Range”, on page 1-37 for details of the range breaks). The resolution parameter is defaulted, leaving it at its current setting. The source list parameter speciﬁes a channel B measurement. The measurement is displayed on the lower window.

speciﬁes expected power value

speciﬁes window speciﬁes channel

MEAS2? -50,DEF,(@2)

HP EPM-441A/442A Programming Guide 1-13

Power Meter Remote Operation

Making Measurements

Example 4 - Specifying the Resolution Parameter

The previous examples detailed the use of the expected value and source list parameters. The resolution parameter is used to set the resolution of the speciﬁed window. This parameter does not affect the resolution of the HP-IB data, however it does affect the auto averaging setting (refer to Figure 1-2 on page 1-39).

Since the ﬁlter length used for a channel with auto-averaging enabled is dependent on the window resolution setting, a conﬂict arises when a given channel is set up in both windows and the resolution settings are different. In this case, the higher resolution setting is used to determine the ﬁlter length.

The following example uses the resolution parameter to specify a resolution setting of 3. This setting represents 3 signiﬁcant digits if the measurement sufﬁx is W or %, and 0.01 dB if the sufﬁx is dB or dBm (for further details on the resolution parameter refer to the commands in Chapter 2, “MEASurement Instructions”.). Also, in this example the expected power and source list parameters are defaulted. The expected power value will be left unchanged at its current setting. The source list parameter will be defaulted as described in the note on page 1-15. Note that as the source list parameter is the last speciﬁed parameter you do not have to specify DEF. The measurement is carried out on the upper window .

speciﬁes window speciﬁes resolution setting

MEAS1? DEF,3

Example 5 - Making a Difference Measurement

The following command can only be carried out on the HP EPM-442A. It queries the lower window to make a difference measurement of channelB-channel A . The expected power and resolution parameters are defaulted, leaving them at their current settings.

speciﬁes between which channels

speciﬁes window

the difference is calculated

MEAS2:POW:AC:DIFF? DEF,DEF,(@2),(@1)

Channel B - A

1-14 HP EPM-441A/442A Programming Guide

Example 6 - Making a Ratio Measurement

The following command can only be carried out on the HP EPM-442A. It queries the upper window to make a ratio measurement of channel A/B . The expected power and resolution parameters are defaulted, leaving them at their current settings.

speciﬁes window

MEAS1:POW:AC:RAT? DEF,DEF,(@1),(@2)

Note HP EPM-442A only

The operation of the MEASure? command when the source list parameter is defaulted depends on the current setup of the window concerned (for example, A, B, A/B, A-B etc.) and on the particular command used (for example, MEAS[:POW][:AC]? and MEAS:POW:AC:RAT? etc).

Power Meter Remote Operation

Making Measurements

speciﬁes the relationship of the channels in the ratio

Channel A / B

This means that when the source list parameter is defaulted, there are a number of possibilities.

Command Current Window Setup Measurement

MEAS1[:POW][AC]? Upper Window: A A

BB Any Other A

MEAS2[:POW][AC]? Lower Window: A A

BB Any Other B

MEAS1:POW:AC:RAT Upper Window: A/B A/B

B/A B/A Any Other A/B

HP EPM-441A/442A Programming Guide 1-15

Power Meter Remote Operation

Making Measurements

Command Current Window Setup Measurement

MEAS2:POW:AC:RAT Lower Window: A/B

B/A Any Other

MEAS1:POW:AC:DIFF? Upper Window: A-B

B-A Any Other

MEAS2:POW:AC:DIFF? Lower Window: A-B

B-A Any Other

A/B B/A A/B A-B B-A A-B A-B B-A A-B

1-16 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Making Measurements

Using the CONFigure Command

When you execute this command, the power meter presets the best settings for the requested conﬁguration (like the MEASure? query). However, the measurement is not automatically started and you can change measurement parameters before making measurements. This allows you to incrementally change the power meter’s conﬁguration from the preset conditions. The power meter offers a variety of low-level commands in the SENSe, CALCulate, and TRIGger subsystems. For example, if you want to change the averaging use the [SENSe[1]]|SENSe2:AVERage:COUNt command.

Use the INITiate or READ? query to initiate the measurement.

Using READ?

CONFigure does not take the measurement. One method of obtaining a result is to use the READ? query. The READ? query takes the measurement using the parameters set by the CONFigure command then sends the reading to the output buffer. Using the READ? query will obtain new data.

Using INITiate and FETCh?

CONFigure does not take the measurement. One method of obtaining the result is to use the INITiate and FETCh? commands. The INITiate command causes the measurement to be taken. The FETCh? query retrieves a reading when the measurement is complete, and sends the reading to the output buffer. FETCh? can be used to display the measurement results in a number of different formats (for example, A/B and B/A) without taking fresh data for each measurement.

CONFigure Examples

The following program segments show how to use the READ? command and the INITiate and FETCh? commands with CONFigure to make measurements.

It is advisable to read through these examples in order as they become increasingly more detailed.

These examples give an overview of the CONFigure command. F or further information on the CONFigure commands refer to Chapter 2, “MEASurement Instructions”.

HP EPM-441A/442A Programming Guide 1-17

Power Meter Remote Operation

Making Measurements

Example 1 - The Simplest Method

The following program segments show the simplest method of querying the upper and lower window’s measurement results respectively.

Using READ?

*RST Reset instrument CONF1 Conﬁgure upper window - defaults to a channel A

measurement

READ1? Take upper window (channel A) measurement *RST Reset instrument

CONF2 Conﬁgure the lower window - defaults to channel A

(HP EPM-441A), Channel B (HP EPM-442A) measurement

READ2? Take lower window measurement (channel A on

HP EPM-441A, B on HP EPM-442A)

Using INITiate and FETCh?

*RST Reset instrument CONF1 Conﬁgure upper window - defaults to a channel A

measurement

INIT1 Causes channel A to make a measurement FETC1? Retrieves the upper window’s measurement

For the HP EPM -441A only:

*RST Reset instrument CONF2 Conﬁgure lower window - HP EPM-441A defaults to channel A INIT1? Causes channel A to make measurement FETC2? Retrieves the lower window’s measurement

For the HP EPM-442A only:

*RST Reset instrument CONF2 Conﬁgure lower window INIT2? Causes channel B to make measurement FETC2? Retrieves the lower window’s measurement

1-18 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Making Measurements

Example 2 - Specifying the Source List Parameter

The CONFigure and READ? commands have three optional parameters, an expected power value, a resolution and a source list. These parameters must be entered in the speciﬁed order . If parameters are omitted, they will default from the right. The parameter DEFault is used as a place holder.

The following examples use the source list parameter to specify the measurement channel as channel A. The expected power and resolution parameters are defaulted, leaving them at their current settings. The measurement is carried out on the upper window.

Although the READ? and FETCh? queries have three optional parameters it is not necessary to deﬁne them as shown in these examples. If they are deﬁned they must be identical to those deﬁned in the CONFigure command otherwise an error occurs.

Note For the HP EPM-441A it is not necessary to specify a channel as

only one channel is available.

Using READ?

ABOR1 Aborts channel A CONF1 DEF,DEF,(@1) Conﬁgures the upper window to

make a channel A measurement using the current expected power and resolution settings.

READ1? Takes the upper window’s

measurement.

Using INITiate and FETCh?

ABOR1 Aborts channel A CONF1 DEF,DEF,(@1) Conﬁgures the upper window to

make a channel A measurement using the current expected power and resolution settings.

INIT1 Causes channel A to make a

measurement.

FETC1? Retrieves the upper window’s

measurement.

HP EPM-441A/442A Programming Guide 1-19

Power Meter Remote Operation

Making Measurements

Example 3 - Specifying the Expected Power Parameter

The previous example details the three optional parameters which can be used with the CONFigure and READ? commands. The ﬁrst optional parameter is used to enter an expected power value. Entering this parameter is only relevant if you are using an HP E-series power sensor. The value entered determines which of the power sensor’s two ranges is used for the measurement. If the current setting of the power sensor’s range is no longer valid for the new measurement, specifying the expected power value decreases the time taken to obtain a result.

The following example uses the expected value parameter to specify a value of -50 dBm. This selects the power meter’s lower range (refer to “Range”, on page 1-37 for details of the range breaks). The resolution parameter is defaulted, leaving it at its current setting. The source list parameter speciﬁes a channel B measurement. The measurement is carried out on the upper window.

Using READ?

ABOR2 Aborts channel B CONF1 -50,DEF,(@2) Conﬁgures the upper window to

make a channel B measurement using an expected power of

-50 dBm and the current resolution setting.

READ1? Takes the upper window’s

measurement.

Some ﬁne tuning of measurements can be carried out using the CONFigure and READ? commands. For example, in the above program segment some ﬁne tuning can be carried out by setting the ﬁlter length to 1024 and the trigger delay off.

ABOR2 CONF1 -50,DEF,(@2) SENS2:AVER:COUN 1024 TRIG2:DEL:AUTO OFF READ1?

1-20 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Making Measurements

Using INITiate and FETCh?

ABOR2 Aborts channel B CONF1 -50,DEF,(@2) Conﬁgures the upperwindow to

make a channel B measurement using an expected power of

-50 dBm and the current resolution setting.

INIT2 Causes channel B to make a

measurement.

FETC1? Retrieves the upper window’s

measurement.

Some ﬁne tuning of measurements can be carried out using the CONFigure command and INITiate and FETCh? commands. For example, in the above program segment some ﬁne tuning can be carried out by setting the ﬁlter length to 1024 and the trigger delay off.

ABOR2 CONF1 -50,DEF,(@2) SENS2:AVER:COUN 1024 TRIG2:DEL:AUTO OFF INIT2 FETC1?

HP EPM-441A/442A Programming Guide 1-21

Power Meter Remote Operation

Making Measurements

Example 4 - Specifying the Resolution Parameter

The following example uses the resolution parameter to specify a resolution setting of 3. This setting represents 3 signiﬁcant digits if the measurement sufﬁx is W or %, and 0.01 dB if the sufﬁx is dB or dBm (for further details on the resolution parameter refer to the commands in Chapter 2, “MEASurement Instructions”). Also, in this example the expected power and source list parameters are defaulted. The expected power value will be left unchanged at its current setting. The source list parameter will be defaulted as described in the note on page 1-15. Note that as the source list parameter is the last speciﬁed parameter you do not have to specify DEF.

Using READ?

ABOR1 Aborts channel A. CONF1 DEF,3 Conﬁgures the upper window to make a

measurement using the current setting of the expected power and source list and a resolution setting of 3.

READ1? T akes the upper window’s measurement. T his will be

a channel A or B measurement depending on current window setup

Some ﬁne tuning of the above program segment can be carried out for example, by setting the trigger delay off. The following program segment assumes that channel A is currently being measured on the upper window.

ABOR1 CONF1 DEF,3 TRIG1:DEL:AUTO OFF READ1?

Using INITiate and FETCh?

1-22 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Making Measurements

The following program segment assumes that channel A is currently being measured on the upper window.

ABOR1 Aborts channel A. CONF1 DEF,3 Conﬁgures the upper window to

make a measurement using the current setting of the expected power and source list and a resolution setting of 3.

INIT1 Causes channel A to make a

measurement.

FETC1? Retrieves the upper window’s

measurement.

Some ﬁne tuning of the above program segment can be carried out for example, by setting the trigger delay off.

ABOR1 CONF1 DEF,3 TRIG1:DEL:AUTO OFF INIT1:IMM FETC1?

HP EPM-441A/442A Programming Guide 1-23

Power Meter Remote Operation

Making Measurements

Example 5 - Making a Difference Measurement

The following program segment can be carried out on the HP EPM-442A. It queries the lower window to make a difference measurement of channelA-channel B. The expected power level and resolution parameters are defaulted, leaving them at their current settings. Some ﬁne tuning of the measurement is carried out by setting the averaging, and the trigger delay to off.

Using READ?

ABOR1 ABOR2 CONF2:POW:AC:DIFF DEF,DEF,(@1),(@2) SENS1:AVER:COUN 1024 SENS2:AVER:COUN 1024 TRIG1:DEL:AUTO OFF TRIG2:DEL:AUTO OFF READ2:POW:AC:DIFF? READ2:POW:AC:DIFF? DEF,DEF,(@2),(@1)(A second

READ?

query is sent to make a channel B - channel A measurement using fresh measurement data.)

Using INITiate and FETCh?

ABOR1 ABOR2 CONF2:POW:AC:DIFF DEF,DEF,(@1),(@2) SENS1:AVER:COUN 1024 SENS2:AVER:COUN 1024 TRIG1:DEL:AUTO OFF TRIG2:DEL:AUTO OFF INIT1:IMM INIT2:IMM FETC2:POW:AC:DIFF? FETC2:POW:AC:DIFF? DEF,DEF,(@2),(@1) (A second FETCh? query is

sent to make a channel B - channel A measurement using the current measurement data.)

1-24 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Making Measurements

Example 6 - Making a Ratio Measurement

The following program segment can be carried out on the HP EPM-442A. It queries the lower window to make a ratio measurement of channel A/B. The expected power level and resolution parameters are defaulted, leaving them at their current settings. Some ﬁne tuning of the measurement is carried out by setting the averaging.

Using READ?

ABOR1 ABOR2 CONF2:POW:AC:RAT DEF,DEF,(@1),(@2) SENS1:AVER:COUN 512 SENS2:AVER:COUN 256 READ2:POW:AC:RAT? READ2:POW:AC:RAT? DEF,DEF,(@2),(@1) (A second

READ?

query is sent to make a channel B - channel A ratio measurement using fresh measurement data.)

Using INITiate and FETCh?

ABOR1 ABOR2 CONF2:POW:AC:RAT DEF,DEF,(@1),(@2) SENS1:AVER:COUN 512 SENS2:AVER:COUN 256 INIT1:IMM INIT2:IMM FETC2:POW:AC:RAT? FETC2:POW:AC:RAT? DEF,DEF,(@2),(@1) (A second FETCh? query is

sent to make a channel B - channel A measurement using the current measurement data.)

HP EPM-441A/442A Programming Guide 1-25

Power Meter Remote Operation

Making Measurements

Using the Lower Level Commands

An alternative method of making measurements is to use the lower level commands to set up the expected range and resolution. This can be done using the following commands:

[SENSe[1]]|SENSe2:POWER:AC:RANGe DISPlay[:WINDow[1|2]]:RESolution

The measurement type can be set using the following commands in the

CALCulate subsystem: CALCulate[1|2]:MATH[:EXPRession]

CALCulate[1|2]:RELative[:MAGNitude]

The advantage of using the lower level commands over the CONFigure command is that they give you more precise control of the power meter . As shown in Table 1-2 on page 1-11 the CONFigure command presets various states in the power meter. It may be likely that you do not want to preset these states.

Example

The following example sets the expected power value to -50 dBm and the resolution setting to 3 using the lower level commands. The measurement is a single channel A measurement carried out on the lower window.

ABOR1 Aborts channel A. CALC2:MATH:EXPR "(SENS1)" Displays channel A on lower

window.

SENS1:POW:AC:RANG 0 Sets lower range (E-series sensors

only).

DISP:WIND2:RES 3 Sets the lower window’s resolution

to setting 3.

INIT1 Causes channel A to make a

measurement.

FETC2? Retrieves the lower window’s

measurement.

1-26 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Using Sensor Calibration Tables

This section applies to all HP 8480 series power sensors. It does not apply to the HP E-series power sensors. The HP E-series power sensors have their sensor calibration tables stored in EEPROM which allows frequency and calibration factor data to be downloaded by the power meter automatically.

This section describes how to use sensor calibration tables. Sensor calibration tables are used to store the measurement calibration factors, supplied with each power sensor, in the power meter. These calibration factors are used to correct measurement results.

Overview

For the HP 8480 series power sensors there are two methods of providing correction data to the power meter depending on the setting of the

[SENSe[1]]|SENSe2:CORRection:CSET:STATe command. If [SENSe[1]]|SENSe2:CORRection:CSET:STATe is OFF the sensor

calibration tables are not used. To make a calibrated power measurement when [SENSe[1]]|SENSe2:CORRection:CSET:STATe is OFF, perform the following steps:

1. Zero and calibrate the power meter. Before carrying out the calibration set the reference calibration factor for the power meter you are using.

2. Set the calibration factor to the value for the frequency of the signal you want to measure.

3. Make the measurement.

When [SENSe[1]]|SENSe2:CORRection:CSET:STATe is ON , the sensor calibration tables are used, providing you with a quick and convenient method for making power measurements at a range of frequencies using one or more power sensors. Note that with the sensor calibration table selected, the RCF from the table overides any value previously set. The power meter is capable of storing 20 sensor calibration tables of 80 frequency points each.

HP EPM-441A/442A Programming Guide 1-27

Power Meter Remote Operation

Using Sensor Calibration Tables

Figure 1-1 illustrates how sensor calibration tables operate.

Figure 1-1: Sensor Calibration Tables

TABLE 1

RCF

FREQ

CFAC = Calibration Factor

RCF = Reference Calibration Factor

Frequency of the signal you want to measure

CFAC

2 . .

. . . . . . . . .

CFAC

2 . .

. . . . . . . . .

CFAC

TABLE N

FREQ

2 . .

. . . . . . . . .

FREQ

TABLE SELECTED

FREQ

2 . .

. . . . . . . . .

FREQ

RCF CFAC

CFAC

2 . .

. . . . . . . . .

CFAC

RCF

CFAC

2 . .

. . . . . . . . .

CFAC

TABLE 20

RCF

FREQ

CFAC

Reference Calibration Factor used for Power Meter Calibration.

Calibration Factor used to make Measurement. Calculated by the Power Meter using linear interpolation

CFAC

1-28 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Using Sensor Calibration Tables

To use sensor calibration tables you:

1. Edit a sensor calibration table if necessary.

2. Select the sensor calibration table.

3. Enable the sensor calibration table.

4. Zero and calibrate the power meter. The reference calibration factor used during the calibration is automatically set by the power meter from the sensor calibration table.

5. Specify the frequency of the signal you want to measure. The calibration factor is automatically set by the power meter from the sensor calibration table.

6. Make the measurement.

HP EPM-441A/442A Programming Guide 1-29

Power Meter Remote Operation

Using Sensor Calibration Tables

Editing Sensor Calibration Tables

It is not possible to create any additional sensor calibration tables. However, the 20 existing ones can be edited using the MEMory subsystem. To do this:

1. Select one of the existing tables using: MEMory:TABle:SELect <string>. For information on naming sensor calibration tables see “Naming Sensor Calibration Tables”, on page 1-33. For information on the current names which you can select refer to “Listing the Sensor Calibration Table Names”, on page 1-31.

2. Enter the frequency data using:

MEMory:TABle:FREQuency <numeric_value> {,<numeric_value>}

3. Enter the calibration factors using:

MEMory:TABle:GAIN <numeric_value> {,<numeric_value>}. The ﬁrst parameter you enter should be

the reference calibration factor, each subsequent parameter is a calibration factor in the sensor calibration table. This means that entries in the frequency list correspond as shown with entries in the calibration factor list.

Frequency Calibration Factor

Reference Calibration

Factor Frequency 1 Calibration Factor 1 Frequency 2 Calibration Factor 2

Frequency n Calibration Factor n

4. If required, rename the sensor calibration table using: MEMory:TABLe:MOVE <string>,<string>. The ﬁrst <string> parameter identiﬁes the existing table name, and the second identiﬁes the new table name.

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Power Meter Remote Operation

Using Sensor Calibration Tables

Note The legal frequency sufﬁx multipliers are any of the IEEE sufﬁx

multipliers, for example, KHZ, MHZ and GHZ. If no units are speciﬁed the power meter assumes the data is Hz.

PCT is the only legal unit for calibration factors and can be omitted.

The frequency and calibration data must be within range. Refer to the individual commands in Chapter 4 for their speciﬁed ranges.

The number of calibration factor points must be one more than the number of frequency points. This is veriﬁed when the sensor calibration table is selected using

[SENSe[1]]|SENSe2:CORRection:CSET[:SELect] <string>.

Ensure that the frequency points you use cover the frequency range of the signals you want to measure. If you measure a signal with a frequency outside the frequency range deﬁned in the sensor calibration table, then the power meter uses the highest or lowest frequency point in the sensor calibration table to calculate the calibration factor.

To make subsequent editing of a sensor calibration table simpler, it is recommended that you retain a copy of your data in a program.

Listing the Sensor Calibration Table Names

To list the sensor calibration tables currently stored in the power meter, use the following command:

MEMory:CATalog:TABLe?

The power meter returns the data in the form of two numeric parameters and 20 strings representing the stored sensor calibration tables.

• <numeric_value>,<numeric_value>{,<string>} The ﬁrst numeric parameter indicates the amount of memory, in bytes, used for storage of sensor calibration tables. The second parameter indicates the memory, in bytes, available for sensor calibration tables.

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Power Meter Remote Operation

Using Sensor Calibration Tables

Each string parameter returned indicates the name, type and size of a stored sensor calibration table:

• <string>,<type>,<size> The <string>, <type> and <size> are all character data. The <type> is always TABL. The <size> is displayed in bytes.

For example, a sample of the response may look like:

560,8020,“Sensor_1,TABL,220”,”Sensor_2,TABL,340” ....

The power meter is shipped with a set of predeﬁned sensor calibration tables. The data in these sensor calibration tables is based on statistical averages for a range of Hewlett-Packard Power Sensors (see Chapter 2, “Editing Sensor Calibration Tables” in the User’s Guide). These power sensors are:

• DEFAULT

• HP 8481A

• HP 8482A

• HP 8483A

• HP 8481D

• HP 8485A

• R8486A

• Q8486A

• R8486D

• HP 8487A

For further information on naming sensor calibration tables see “Naming Sensor Calibration Tables”, on page 1-33.

1. DEFAULT is a sensor calibration table in which the reference calibration factor and calibration factors are 100%. This sensor calibration table can be used during the performance testing of the power meter.

2. The HP 8482B and HP 8482H power sensors use the same data as the HP 8482A.

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Power Meter Remote Operation

Using Sensor Calibration Tables

Naming Sensor Calibration Tables

To rename a sensor calibration table use:

MEMory:TABLe:MOVE <string>,<string>

The ﬁrst <string> parameter identiﬁes the existing table name, and the second identiﬁes the new table name.

The following rules apply to sensor calibration table names:

a) The sensor calibration table must consist of no more than 12

characters.

b) All characters must be upper or lower case alphabetic characters,

or numeric (0-9), or an underscore (_).

c) No spaces are allowed in the name.

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Power Meter Remote Operation

Using Sensor Calibration Tables

Reviewing Table Data

To review the data stored in a sensor calibration table, use the following commands:

• MEMory:TABLe:SELect "Sense1"

Select the sensor calibration table named “Sense1”.

• MEMory:TABLe:SELect?

Query command which returns the name of the currently selected table.

• MEMory:TABLe:FREQuency:POINTs?

Query command which returns the number of stored frequency points.

• MEMory:TABLe:FREQuency?

Query command which returns the frequencies stored in the sensor calibration table (in Hz).

• MEMory:TABLe:GAIN[:MAGNitude]:POINTs?

Query command which returns the number of calibration factor points stored in the sensor calibration table.

• MEMory:TABLe:GAIN[:MAGNitude]?

Query command which returns the calibration factors stored in the sensor calibration table. The ﬁrst point returned is the reference calibration factor.

Modifying Data

If you need to modify the frequency and calibration factor data stored in a sensor calibration table you need to resend the complete data lists. There are two ways to do this:

1. If you have retained the original data in a program, edit the program and resend the data.

2. Use the query commands shown in “Reviewing Table Data”, on page 1-34 to enter the data into your computer. Edit this data, then resend it.

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Power Meter Remote Operation

Using Sensor Calibration Tables

Selecting a Sensor Calibration Table

After you have created the sensor calibration table, you can select it using the following command:

[SENSe[1]]|SENSe2:CORRection:CSET[:SELect] <string>

When the table is selected, the power meter veriﬁes the number of calibration factor points deﬁned in the sensor calibration table is one parameter greater than the number of frequency points. If this is not the case an error occurs.

To ﬁnd out which sensor calibration table is currently selected, use the query:

[SENSe[1]]|SENSe2:CORRection:CSET[:SELect]?

Enabling the Sensor Calibration Table System

To enable the sensor calibration table, use the following command:

[SENSe[1]]|SENSe2:CORRection:CSET:STATe ON

If you set [SENSe[1]]|SENSe2:CORRection:CSET:STATe to ON and no sensor calibration table is selected error -221, “Settings conﬂict” occurs.

HP EPM-441A/442A Programming Guide 1-35

Power Meter Remote Operation

Using Sensor Calibration Tables

Making the Measurement

To make the power measurement, set the power meter for the frequency of the signal you want to measure. The power meter automatically sets the calibration factor. Use either the INITiate,FETCh? or the READ? query to initiate the measurement as shown in the following program segments:

INITiate Example

ABORt1 CONFigure1:POWer:AC DEF,1,(@1) SENS1:CORR:CSET:SEL "HP8481A" SENS1:CORR:CSET:STAT ON SENSe1:FREQuency 500KHZ INITiate1:IMMediate FETCh1?

READ? Example

ABORt1 CONFigure1:POWer:AC DEF,2,(@1) SENS1:CORR:CSET:SEL "HP8481A" SENS1:CORR:CSET:STAT ON SENSe1:FREQuency 500KHZ READ1?

Note If the measurement frequency does not correspond directly to a

frequency in the sensor calibration table, the power meter calculates the calibration factor using linear interpolation.

If you enter a frequency outside the frequency range deﬁned in the sensor calibration table, then the power meter uses the highest or lowest frequency point in the sensor calibration table to set the calibration factor.

To ﬁnd out the value of the calibration factor being used by the power meter to make a measurement, use the query command: [SENSe[1]]|SENSe2:CORRection:CFAC? The response may be an interpolated value.

To ﬁnd out the value of the reference calibration factor being used, use the commands:

CALibration[1|2]:RCFactor?

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Power Meter Remote Operation

Setting the Range, Resolution and Averaging

This section provides an overview of setting the range, resolution and averaging. For more detailed information about these features refer to the individual commands in Chapter 9.

Range

The power meter has no internal ranges which can be set. The only ranges that can be set are those of the HP E-series power sensors. With an HP E-series power sensor the range can be set either automatically or manually. Use autoranging when you are not sure of the power level you will be measuring.

Setting the Range

To set the range manually use the following command:

[SENSe[1]]|SENSe2:POWer:AC:RANGe <numeric_value>

If the <numeric_value> is set to:

• 0, the sensor’s lower range is selected. (For example, this range is

-70 to -13.5 dBm for the HP ECP-18A power sensor.)

• 1, the sensor’s upper range is selected. (For example, this range is

-14.5 to +20 dBm for the HP ECP-18A power sensor.)

For details on the range limits of other HP E-series power sensors refer to the appropriate power sensor manual.

For further information on this command refer to page 9-48. To enable autoranging use the following command:

[SENSe[1]]|SENSe2:POWer:AC:RANGe:AUTO ON

Use autoranging when you are not sure of the power level you will be measuring.

HP EPM-441A/442A Programming Guide 1-37

Power Meter Remote Operation

Setting the Range, Resolution and Averaging

Resolution

You can set the window’s resolution using the following command:

DISPlay[:WINDow[1|2]]:RESolution <numeric_value>

There are four levels of resolution available (1 through 4). When the measurement sufﬁx is W or % this parameter represents the

number of signiﬁcant digits. When the measurement sufﬁx is dB or dBM, 1 through 4 represents 1, 0.1, 0.01, and 0.001 dB respectively.

For further information refer to the resolution command on page 5-14.

Averaging

The power meter has a digital ﬁlter to average power readings. The number of readings averaged can range from 1 to 1024 in binary progression. This ﬁlter is used to reduce noise, obtain the desired resolution and to reduce the jitter in the measurement results. However, the time to take the measurement is increased. You can select the ﬁlter length or you can set the power meter to auto ﬁlter mode. To enable and disable averaging use the following command:

[SENSe[1]]|SENSe2:AVERage[:STATe] <Boolean>

Note If you are using the HP 437B remote programming language you

cannot enter a value of 1024.

Auto Averaging Mode

To enable and disable auto ﬁlter mode, use the following command:

[SENSe[1]]|SENSe2:AVERage:COUNt:AUTO <Boolean>

When the auto ﬁlter mode is enabled, the power meter automatically sets the number of readings averaged together to satisfy the ﬁltering requirements for most power measurements. The number of readings averaged together depends on the resolution and the power level currently being measured. Figure 1-2 lists the number of readings averaged for each range and resolution when the power meter is in auto ﬁlter mode.

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Power Meter Remote Operation

Setting the Range, Resolution and Averaging

Figure 1-2: Averaged Readings

Minimum Sensor Power

10 dB

Power Sensor

10 dB

Dynamic Range

1234 8 8 128 128

1 1 16 256

11232

11116

1118

Maximum Sensor Power

Figure 1-3 illustrates part of the power sensor dynamic range hysteresis.

Figure 1-3: Averaging Range Hysteresis

Range Hysteresis

Resolution Setting

Number of Averages

10.5 dB9.5 dB

Minimum Sensor Power

Minimum Sensor Power + 10 dB

HP EPM-441A/442A Programming Guide 1-39

Power Meter Remote Operation

Setting the Range, Resolution and Averaging

Filter Length

You specify the ﬁlter length using the following command:

[SENSe[1]]|SENSe2:AVERage:COUNt <numeric_value>

The range of values for the ﬁlter length is 1 to 1024. Specifying this command disables automatic ﬁlter length selection. If a numeric parameter is speciﬁed which is not a binary multiple, the power meter rounds to the nearest power of two. For example, if you specify a ﬁlter length of 5, the power meter rounds the value to 4. Increasing the value of the ﬁlter length reduces measurement noise. However, the time to take the measurement is increased.

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Power Meter Remote Operation

Setting Offsets

Channel Offsets

The power meter can be conﬁgured to compensate for signal loss or gain in your test setup (for example, to compensate for the loss of a 10 dB attenuator). You use the SENSe command subsystem to conﬁgure the power meter. Gain and loss correction are a coupled system. This means that a gain set by [SENSe[1]]|SENSe2:CORRection:GAIN2 is represented in the [SENSe[1]]|SENSe2:CORRection:LOSS2? command. If you enter an offset value the state is automatically enabled. However it can be enabled and disabled using either the

[SENSe[1]]|SENSe2:CORRection:GAIN2:STATe or [SENSe[1]]|SENSe2:CORRection:LOSS2:STATe commands.

LOSS2 is coupled to GAIN2 by the equation when the default

Loss

-------------=

Gain

unit is linear, and when the default is logarithmic.

Note You can only use LOSS2 and GAIN2 for external losses and gains.

LOSS1 and GAIN1 are speciﬁcally for calibration factors.

Gain Loss–=

Display Offsets

Display offset values can be entered using the

CALCulate[1|2]:GAIN[:MAGNitude] command. CALCulate[1|2]:GAIN:STATe must be set to ON to enable the offset

value. If you enter an offset value the state is automatically enabled. On the HP EPM-442A this offset is applied after any math calculations (refer to Figure 1-8 on page 1-58).

HP EPM-441A/442A Programming Guide 1-41

Power Meter Remote Operation

Setting Offsets

Example

The following example program, in HP Basic, details how to use the channel and display offsets on an HP EPM-442A making a channel A/B ratio measurement. The ﬁnal result will be:

10–

dBm



-------------------------- -



dBm

10 !Create I/O path name 20 ASSIGN @POWER TO 713 30 !Clear the power meter’s interface 40 CLEAR @POWER 50 !Set the power meter to a known state 60 OUTPUT @POWER;"*RST" 70 !Configure the Power Meter to make the measurement 80 OUTPUT @Power;"CONF:POW:AC:RAT 20DBM,2,(@1),(@2)" 90 !Set the measurement units to dBm 100 OUTPUT @POWER;"UNIT:POW DBM" 110 !Set the power meter for channel offsets of -10 dB 120 OUTPUT @POWER;"SENS1:CORR:GAIN2 -10" 130 OUTPUT @POWER;"SENS2:CORR:GAIN2 -10" 140 !Enable the gain correction 150 OUTPUT @POWER;"SENS:CORR:GAIN2:STATe ON" 160 OUTPUT @POWER;"SENS2:CORR:GAIN2:STATe ON" 170 !Set the power meter for a display offset of -20 dB 180 OUTPUT @POWER;"CALC1:GAIN -20 DB" 190 PRINT "MAKING THE MEASUREMENT" 200 !Initiate the measurement 210 OUTPUT @Power;"INIT1:IMM" 220 OUTPUT @Power;"INIT2:IMM" 230 ! ... and get the result 240 OUTPUT @Power;"FETC:POW:AC:RAT? 20DBM,2,(@1),(@2)" 250 ENTER @Power;Reading 260 ! 270 PRINT "The measurement result is ";Reading;"dB." 280 END

20–

10–

For further information on channel offsets refer to page 9-23 through page 9-32. For further information on display offsets refer to page 3-3.

1-42 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Setting Measurement Limits

The power meter can be conﬁgured to verify the power being measured against an upper and/or lower limit value. The range of values that can be set for lower and upper limits is -150.00 dBm to +230.00 dBm. The default upper limit is +90.00 dBm and the default lower limit is -90.00 dBm.

A typical application for this feature is shown in Figure 1-4.

Figure 1-4: Limits Checking Application

Power Meter

Swept Source

Device Under Test

OUT

CHANNEL A INPUT

Figure 1-5: Limits Checking Results

Amplitude

10 dBm

Fail o

4 dBm

o Fail

Frequency

HP EPM-441A/442A Programming Guide 1-43

Power Meter Remote Operation

Setting Measurement Limits

In this application a swept frequency signal is applied to the input of the Device Under Test. The power meter measures the output power. The limits have been set at +4 dBm and +10 dBm. A fail occurs each time the output power is outside these limits. Use the SENSe subsystem to conﬁgure the power meter for limits checking. The following example program, in HP Basic, shows how to set the limits to +4 dBm and +10 dBm.

10 !Create I/O path name 20 ASSIGN @Power to 713 30 !Clear the Power Meter’s Interface 40 CLEAR @Power 50 !Set the Power Meter to a known state 60 OUTPUT @Power;“*RST” 70 !Set the measurement units to dBm 80 OUTPUT @Power;“UNIT:POWer DBM” 90 !Set the upper limit to 10 dBm 100 OUTPUT @Power;“SENSe:LIMit:UPPer 10” 110 !Set the lower limit to 4 dBm 120 OUTPUT @Power;“SENSe:LIMit:LOWer 4” 130 !Switch the limit checking on 140 OUTPUT @Power;“SENSe:LIMit:STATe ON” 150 !Check the limits 160 OUTPUT @Power;“SENSe:LIMit:UPPer?” 170 ENTER @Power;A 180 OUTPUT @Power;“SENSe:LIMit:LOWer?” 190 ENTER @Power;B 200 PRINT A,B 210 END

Checking for Limit Failures

There are two ways to check for limit failures; using the SENSe:LIMit:FAIL? and the SENSe:LIMit:FCOunt? commands or using the STATus command subsystem.

1-44 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Setting Measurement Limits

Using SENSe

Using SENSe to check the limit failures in Figure 1-5 would return the following results:

SENSe:LIMit:FAIL? Returns 1 if there has been 1 or

more limit failures or 0 if there have been no limit failures. In this case 1 is returned.

SENSe:LIMit:FCOunt? Returns the total number of

limit failures, in this case 2.

Note If TRIGger:DELay:AUTO is set to ON, then the number of failures

returned by SENSe:LIMit:FCOunt? will be affected by the current ﬁlter settings.

Refer to page 9-40 and page 9-41 for further information on using these commands.

Using STATus

You can use the STATus subsystem to generate an SRQ to interrupt your program when a limit failure occurs. This is a more efﬁcient method than using SENSe, since you do not need to check the limit failures after every power measurement.

Refer to “Status Reporting”, on page 1-59 and “STATus Subsystem”, on page 10-1 for further information.

HP EPM-441A/442A Programming Guide 1-45

Power Meter Remote Operation

Measuring Pulsed Signals

The power meter can be used to measure the power of a pulsed signal. The measurement result is a mathematical representation of the pulse power rather than an actual measurement. The power meter measures the average power of the pulsed input signal and then divides the measurement result by the duty cycle value to obtain the pulse power reading. The allowable range of values is 0.001% to 99.999%. The default is 1.000%. A duty cycle value can be set using the following command:

[SENSe[1]]|SENSe2:CORRection:DCYCle|GAIN3 <numeric_value>

Note Pulse measurements are not recommended using HP ECP series

power sensors.

Making the Measurement

An example of a pulsed signal is shown in Figure 1-6.

Figure 1-6: Pulsed Signal

Power

Duty Cycle = A

Duty Cycle (%) = A x 10

Time

You use the SENSe command subsystem to conﬁgure the power meter to measure a pulsed signal. The following example program, in HP Basic, shows how to measure the signal for the HP 8480 series power sensors.

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Power Meter Remote Operation

Measuring Pulsed Signals

10 !Create I/O path name 20 ASSIGN @Power TO 713

30 !Clear the Power Meter’s Interface 40 CLEAR @Power 50 !Set the Power Meter to a known state 60 OUTPUT @Power;"*RST" 70 !Configure the Power Meter to make the measurement 80 OUTPUT @Power;"CONF:POW:AC 20DBM,2,(@1)" 90 !Set the reference calibration factor for the sensor 100 OUTPUT @Power;"CAL:RCF 98.7PCT" 110 !Zero and calibrate the power meter 120 OUTPUT @Power;"CAL?" 130 PRINT "ZEROING AND CALIBRATING THE POWER METER" 140 !Verify the outcome 150 ENTER @Power;Success 160 IF Success=0 THEN 170 !Calibration cycle was successful 180 !

190 !Set the measurement units to Watts 200 OUTPUT @Power;"UNIT:POW WATT" 210 ! 220 !Set the measurement calibration factor for the

sensor 230 OUTPUT @Power;"SENS:CORR:CFAC 97.5PCT" 240 !Set the power meter for a duty cycle of 16PCT 250 OUTPUT @Power;"SENS1:CORR:DCYC 16PCT" 260 ! 270 !Enable the duty cycle correction 280 OUTPUT @Power;"SENS:CORR:DCYC:STAT ON 290 PRINT "MAKING THE MEASUREMENT"

300 !Initiate the measurement 310 OUTPUT @Power;"INIT1:IMM"

320 !... and get the result 330 OUTPUT @Power;"FETC?"

340 ENTER @Power;Reading 350 ! 360 PRINT "The result is ";Reading*1000;"mW" 370 ! 380 ELSE 390 PRINT "THERE WAS A CALIBRATION ERROR!" 400 END IF 410 PRINT "PROGRAM COMPLETED" 420 END

HP EPM-441A/442A Programming Guide 1-47

Power Meter Remote Operation

Measuring Pulsed Signals

Note Pulse power averages out any aberrations in the pulse such as

overshooting or ringing. For this reason it is called pulse power and not peak power or peak pulse power.

In order to ensure accurate pulse power readings, the input signal must be pulsed with a rectangular pulse. Other pulse shapes (such as triangle, chirp or Gaussian) will cause erroneous results.

The pulse power on/off ratio must be much greater than the duty cycle ratio.

1-48 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Triggering the Power Meter

Triggering is a feature that is only available via remote programming of the power meter.

The power meter has two modes of operation, standby mode and free run mode. During local operation the power meter is always in free run mode. During remote operation the power meter can operate in either free run mode or standby mode and can be switched between modes at any time.

a) Standby mode means the power meter is making measurements,

but the display and HP-IB are not updated until a trigger command is received. In this mode the power meter is either waiting to be initiated, or waiting for a trigger (See “Trigger System” on page 51.).

b) Free run mode is the preset mode of operation and is identical to

local operation. The measurement result data available to the HP-IB is continuously updated as rapidly as the power meter makes measurements. Entry into local mode via sets the power meter to free run mode In this mode INITiate:CONTinuous is set to ON and TRIGger:SOURce is set to IMMediate.

Preset Local

To obtain accurate measurements, ensure that the input power to the power sensor is settled before making a measurement.

The trigger conﬁguration is automatically set by the MEASure? command. If you want to use the lower level commands (READ? or INITiate), you need to understand the power meter’s trigger model.

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Power Meter Remote Operation

Triggering the Power Meter

Triggering the power meter from the remote interface is a process that offers triggering ﬂexibility. The process is:

1. Specify the source from which the power meter will accept the trigger. The trigger source speciﬁes which event causes the trigger system to travel through the event detection state. See “Event Detection State”, on page 1-52 for details.

2. Make sure that the power meter is ready to accept a trigger. This is called the “wait-for-trigger” state . Sending a device clear, a *RST or an ABORt forces the trigger system into the idle state. The trigger system remains in the idle state until it is moved into the “wait-for-trigger” state by executing an INITiate command.

The “wait-for-trigger” state is a term used only for remote interface operation.

The TRIGger commands are used to synchronize power meter actions with speciﬁed events. Figure 1-7 summarizes the power meter’s trigger system.

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Power Meter Remote Operation

Triggering the Power Meter

Figure 1-7: Trigger System

TRIG:SOUR IMM TRIG:SOUR BUS TRIG:SOUR HOLD

SEQUENCE

OPERATION

STATE

IDLE

STATE

TRIG:SOURce

:ABORt

*RST

Idle State

INIT[:IMM]

INIT:CONT ON

YES

Wait - for - trigger

TRIG:DEL

Wait

TRIGGERED

Power Meter Measurement Actions

state

YES

INIT:CONT ON

TRIG:IMMediate

INITIATE

STATE

EVENT

DETECTION

STATE

Idle State

Turning power on, sending an HP-IB CLEAR, sending a *RST or an :ABORt forces the trigger system into the idle state. The trigger system remains in the IDLE state until it is initiated by INITiate:CONTinuous ON or INITiate:IMMediate. Once one of these conditions is satisﬁed the trigger system moves to the initiate state.

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Power Meter Remote Operation

Triggering the Power Meter

Initiate State

If the trigger system is on the downward path, it travels directly through the initiate state without any restrictions. If the trigger system is on the upward path, and INIT iate:CONTinuous is ON , it exits downwards to the event detection state. If the trigger system is on the upward path and INITiate:CONTinuous is OFF, it exits upwards to the idle state.

Event Detection State

The trigger source speciﬁes which event causes the trigger system to travel through the event detection state. The trigger source is set with the following command:

TRIGger:SOURce

There are three possible trigger sources.

• BUS The trigger source is the HP-IB group execute trigger (<GET>), a *TRG command, or the TRIGger:IMMediate command.

• HOLD Triggering is suspended. The only way to trigger the power meter is to send TRIGger:IMMediate.

• IMMediate The power meter does not wait for any event and immediately travels through the event detection state.

Querying the Trigger Source

The trigger source is queried with the following command:

TRIGger:SOURce

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Triggering the Power Meter

Trigger Delay

The power meter has the ability to insert a delay between receiving a trigger and making the measurement. The delay is automatically calculated by the power meter and depends on the current ﬁlter length. The delay ensures that the analog circuitry and the digital ﬁlters in the power meter have settled. It does not allow time for power sensor delay.

To enable the delay, use the following command:

TRIGger:DELay:AUTO ON

To disable the delay, use the following command:

TRIGger:DELay:AUTO OFF

Note MEASure? and CONFigure automatically enable the delay.

Also, when the power meter is ﬁrst powered on the delay is enabled. For the fastest possible measurements the delay should be disabled.

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Power Meter Remote Operation

Getting the Best Speed Performance

This section discusses the factors that inﬂuence the speed of operation (number of readings/sec) of an HP EPM-441/2A power meter.

The following factors are those which have the greatest effect upon measurement speed (in no particular order):

• The selected speed i.e. 20, 40 or 200 readings/sec.

• The trigger mode (for example, free run, trigger with delay etc.).

• The output format i.e. ASCii or REAL.

• The units used for the measurement.

• The command used to take a measurement.

In addition, in 200 reading/sec mode there are other inﬂuences which are described in “200 Readings/Sec”, on page 1-56.

The following paragraphs give a brief description of the above factors and how they are controlled from SCPI.

Speed

There are three possible speed settings 20, 40 and 200 readings/sec. These are set using the SENSe:SPEed command and can be applied to each channel independently (HP EPM-442A only). The speed setting controls the cycle time of the measurement i.e., 50ms, 25ms and 5ms respectively.

In 20 and 40 readings/sec mode, full instrument functionality is available; 200 readings/sec is available only for E-series sensors and averaging, offsets, limits, and ratio/difference math functions are disabled.

Refer to “Speciﬁcations” in chapter 5 of the User’s Guide to see the inﬂuence of these speed settings on the accuracy and noise performance of the power meter.

Trigger Mode

The power meter has a very ﬂexible triggering system. For simplicity, it can be described as having three modes:

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Getting the Best Speed Performance

Free run

A channel is in free run whenINITiate:CONTinuous is set to ON and TRIGger:SOURce is set to IMMediate.

Trigger immediate

There are a variety of methods to achieve this:

TRIG:DEL:AUTO OFF INIT:CONT OFF TRIG:SOUR IMM INIT

TRIG:SOUR BUS INIT:CONT ON TRIG

TRIG:DEL:AUTO OFF TRIG:SOUR BUS INIT:CONT ON GET or *TRG

TRIG:DEL:AUTO OFF INIT:CONT OFF TRIG:SOUR IMM READ?

Trigger with delay

This can be achieved using the same sequences above (apart from the second) with TRIG:DEL:AUTO set to ON. Also, the MEAS? command operates in trigger with delay mode.

In trigger with delay mode, a measurement is not completed until the power meter ﬁlter is full. In this way, the reading returned is guaranteed to be settled. In all other modes, the result returned is simply the current result from the ﬁlter and may or may not be settled. This depends on the current length of the ﬁlter and the number of readings that have been taken since a change in power level.

With trigger with delay enabled, the measurement speed can be calculated roughly using the following equation:

readings/sec = speed (as set by SENSe:SPEed) / ﬁlter length

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Power Meter Remote Operation

Getting the Best Speed Performance

For example, with a ﬁlter length of 4 and SENS:SPE set to 20, approximately 5 readings/sec will be calculated by the power meter.

In general, free run mode will provide the best speed performance from the power meter (especially in 200 readings/sec mode).

Output Format

The power meter has two output formats for measurement results: ASCii and REAL. These formats can be selected using the FORMat command. When FORMat is set to REAL, the result returned is in IEEE 754 ﬂoating-point format (note that the byte order can be changed using FORMat:BORDer).

The REAL format is likely to be required only for 200 readings/sec mode as a means to reduce bus trafﬁc.

Units

The power meter can output results in either linear or log units. The internal units are linear and therefore optimal performance will be acheived when the results output are also in linear units (since the overhead of performing a log function is removed).

Command Used

In free run trigger mode, FETC? must be used to retrieve a result. In other trigger modes, there are a number of commands which can be used,

for example, MEAS?, READ?, FETC? Note that the MEAS? and READ? commands are compound commands i.e., they perform a combination of other lower level commands. In general, the best speed performance will be achieved using the low level commands directly.

200 Readings/Sec

In the highest speed setting, the limiting factor tends to be the speed of the controller being used to retrieve results from the power meter and to a certain extent the volume of HP-IB trafﬁc. The latter can be reduced using the FORMat REAL command to return results in binary format. The former is a combination of two factors:

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Getting the Best Speed Performance

• the hardware platform being used.

• the programming environment being used.

Note that it is unlikely that 200 readings/sec can be achieved when:

• you are using a 700 series HPUX workstation.

• you are using a low end PC.

• you are using a graphical programming environment (such as HP VEE).

Dual Channel Considerations

With the dual channel instrument, consideration must be taken of what operation is required on both channels. Both channels can achieve 20 readings/sec simultaneously, and 40 readings/sec simultaneously, but 200 readings/sec is not achievable on both channels at the same time. If only single channel measurements are required, then the other channel should be set to standby mode and not triggered.

The throughput for a channel set in the 200 readings/sec mode will be affected by the speed mode of the other channel. However, in a situation where fast measurements are required on one channel and slow measurements on the other, it will be possible to perform more than one measurement cycle on the fast channel for every measurement on the slow channel. For example , if channel A is set to 40 readings /sec and channel B is set to 20 readings/sec, it is possible to construct a loop with 2 reads from channel A and one from channel B and still achieve the set readings per second.

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Power Meter Remote Operation

How Measurements are Calculated

Figure 1-8 details how measurements are calculated. It shows the order in which the various power meter functions are implemented in the measurement calculation.

Figure 1-8: How Measurements are Calculated

Upper Measurement Window

CALCulate1

Sensor A

:AVER1

Sensor A

:GAIN1

:GAIN2

:LIMit

:GAIN3

SENSe1

:MATH

“A” | “B”

“A-B” | “B-A”

“A/B” | “B/A”

:GAIN

:REL

UNIT1:POW

UNIT1:POW:RAT

MEAS1:POW:AC?

MEAS1:POW:AC:DIFF?

MEAS1:POW:AC:REL?

MEAS1:POW:AC:DIFF:REL?

MEAS1:POW:AC:RAT:REL?

MEAS1:POW:AC:RAT?

HPIB

FORMat

MEAS2:POW:AC:RAT?

MEAS2:POW:AC:RAT:REL?

MEAS2:POW:AC:DIFF:REL?

MEAS2:POW:AC:REL?

MEAS2:POW:AC:DIFF?

MEAS2:POW:AC?

:AVER1 :GAIN1 :GAIN3:GAIN2

SENSe2

Sensor B

:LIMit

Upper Measurement Window

“A/B” | “B/A” “A-B” | “B-A”

“A” | “B”

:MATH

CALCulate2

:GAIN

Lower Measurement Window

:REL

UNIT2:POW:RAT

UNIT2:POW

The MEASure commands in this ﬁgure can be replaced with the FETCh? and READ? commands.

Note All references to channel B in the above diagram refer to the

HP EPM-442A only. The MEAS[1|2]:POW:AC? and MEAS[1|2]:POW :AC:REL? are the only commands relevant to the HP EPM-441A.

HP-IB

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Power Meter Remote Operation

Status Reporting

Status reporting is used to monitor the power meter to determine when events have occurred. Status reporting is accomplished by conﬁguring and reading status registers. The power meter has the following main registers:

• Status Register

• Standard Event Register

• Operation Status Register

• Questionable Status Register

• Device Status Register

There are a number of other registers “behind” these. These are described later.

The Status and Standard Event registers are read using the IEEE-488.2 common commands. These are the most commonly used registers and are described in detail in this section.

The Operation and Questionable Status registers are read using the SCPI STATus command subsystem.

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Power Meter Remote Operation

Status Reporting

The General Status Register Model

The generalized status register model shown in Figure 1-9 is the building block of the SCPI status system. This model consists of a condition register, a transition ﬁlter, an event register and an enable register. A set of these registers is called a status group.

Figure 1-9: Generalized Status Register Model

Condition

Bit 0 Bit 1

1 2

Bit 2 Bit 3

When a status group is implemented in an instrument, it always contains all of the component registers. However, there is not always a corresponding command to read or write to every register.

Transition

Filter

Event

Enable

Logical OR

Summary

Bit

Condition Register

The condition register continuously monitors the hardware and ﬁrmware status of the power meter. There is no latching or buffering for this register, it is updated in real time. Condition registers are read-only.

Transition Filter

The transition ﬁlter speciﬁes which types of bit state changes in the condition registers will set corresponding bits in the event register. Transition ﬁlter bits may be set for positive transitions (PTR), negative transitions (NTR), or both. Transition ﬁlters are read-write. They are unaffected by *CLS or queries. After STATus:PRESet the NTR register is set to 0 and all bits of the PTR are set to 1.

Event Register

The event register latches transition events from the condition register as speciﬁed by the transition ﬁlter. Bits in the event register are latched and once set they remain set until cleared by a query or a *CLS. Once set, an event bit is no longer affected by condition changes. It remains set until the event register is cleared; either when you read the register or when you send the *CLS (clear status) command. Event registers are read-only.

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Status Reporting

Enable Register

The enable register speciﬁes the bits in the event register that can generate a summary bit. The instrument logically ANDs corresponding bits in the event and enable registers and ORs all the resulting bits to obtain a summary bit. Enable registers are read-write. Querying an enable register does not affect it.

An Example Sequence

Figure 1-10 illustrates the response of a single bit position in a typical status group for various settings. The changing state of the condition in question is shown at the bottom of the ﬁgure. A small binary table shows the state of the chosen bit in each status register at the selected times T1 to T5.

Figure 1-10: Typical Status Register Bit Changes

Case A Case B Case C Case D

PTR

00 01

Condition

Summary Bit

Condition

Enable

NTR

0000

000

110

000

011

1 0

***

Summary Bit

Condition

Event

T1 T2 T3

Event

0 0 11

011

1 1 1 1

marks when event register is read

Condition

Event

0 0 0 0

Summary Bit

0 0 0

Condition

00 01 000

Summary Bit

Event

0100

Condition

Event

Summary Bit

0 0

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Status Reporting

How to Use Registers

There are two methods you can use to access the information in status groups:

• the polling method, or

• the service request (SRQ) method.

Use the polling method when:

• your language/development environment does not support SRQ interrupts.

• you want to write a simple, single purpose program and do not want to add the complexity of setting an SRQ handler.

Use the SRQ method when you:

• need time critical notiﬁcation of changes.

• are monitoring more than one device which supports SRQ interrupts.

• need to have the controller do something else while it’s waiting.

• cannot afford the performance penalty inherent to polling.

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Status Reporting

The Condition Polling Method

In this polling method, the power meter has a passive role. It only informs the controller that conditions have changed when the controller asks. When you monitor a condition with the polling method, you must:

1. Determine which register contains the bit that monitors the condition.

2. Send the unique HP-IB query that reads that register.

3. Examine the bit to see if the condition has changed.

The polling method works well if you do not need to know about the changes the moment they occur. The SRQ method is more effective if you must know immediately when a condition changes. Detecting an immediate change in a condition using the polling method requires your program to continuously read the registers at very short intervals. This is not particularly efﬁcient and there is a possibility that an event may be missed.

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Power Meter Remote Operation

Status Reporting

The SRQ Method

When a bit of the Status Register is set and has been enabled to assert SRQ (*SRE command), the power meter sets the HP-IB SRQ line true. This interrupt can be used to interrupt your program to suspend its current operation and ﬁnd out what service the power meter requires. (Refer to your computer and language manuals for information on how to program the computer to respond to the interrupt).

To allow any of the Status Register bits to set the SRQ line true, you have to enable the appropriate bit(s) with the *SRE command. For example, suppose your application requires an interrupt whenever a message is available in the output queue (Status Register bit 4, decimal weight 16). To enable bit 4 to assert SRQ, you use the following command:

*SRE 16

Note You can determine which bits are enabled in the Status Register

using *SRE?. This command returns the decimal weighted sum of all the bits.

Procedure

• Send a bus device clear message.

• Clear the event registers with the *CLS (clear status) command.

• Set the *ESE (standard event register) and *SRE (status byte register) enable masks.

• Enable your bus controller’s IEEE-488 SRQ interrupt.

Examples

The following two examples are written in HP BASIC and illustrate possible uses for SRQ. In both cases , it is assumed that the meter has been zeroed and calibrated.

Example 1:

10 ! Program to generate an SRQ when a channel A sensor 20 ! connect or disconnect occurs 30 ! 40 ASSIGN @Pm TO 713 ! Power meter HPIB address 50 ON ON INTR 7 GOTO Srq_i! Define service request handler 60 CLEAR @Pm ! Selective device clear 70 OUTPUT @Pm;”*CLS;*RST” ! Clear registers and reset meter 80 !

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90 ! Configure the device status register so that a sensor 100 ! connect or disconnect on channel A will cause an SRQ. 110 ! 120 OUTPUT @Pm;”STAT:DEV:ENAB 2” 130 OUTPUT @Pm;”STAT:DEV:NTR 2” 140 OUTPUT @Pm;”STAT:DEV:PTR 2” 150 OUTPUT @Pm;”*SRE 2” 160 ! 170 ENABLE INTR 7;2 ! Enable an SRQ to cause an interrupt 180 LOOP ! Idle loop 190 ! Forever 200 END LOOP 210 ! 220 ! When a SRQ is detected , the following routine will

service it. 230 ! 240 Srq_i: ! 250 St=SPOLL(@Pm) ! Serial Poll (reads status byte) 260 IF BIT(St,1)=1 THEN ! Device status reg bit set ? 270 OUTPUT @Pm;”STAT:DEV:EVEN?” ! Yes , read register 280 ENTER @Pm;Event ! (this also clears it) 290 OUTPUT @Pm;”STAT:DEV:COND?” 300 ENTER @Pm;Cond 310 IF Cond=0 THEN 320 PRINT “Sensor disconnected” 330 ELSE 340 PRINT “Sensor connected” 350 END IF 360 END IF 370 GOTO 170 ! Return to idle loop 380 END

Example 2:

10 ! Program to generate an SRQ when an over limit 20 ! condition occurs. 30 ! 40 ASSIGN @Pm TO 713 ! Power meter HPIB address 50 ON INTR 7 GOTO Srq_i ! Define service request handler 60 CLEAR @Pm ! Selective device clear 70 OUTPUT @Pm;”*CLS” ! Clear registers 80 OUTPUT @Pm;”SYST:PRES” ! Preset meter 90 !

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Status Reporting

100 ! Set upper limit to 2dBm and configure the operation

status 110 ! so that an over limit condition will cause an SRQ. 120 ! 130 OUTPUT @Pm;”SENS:LIM:UPP 2DBM” 140 OUTPUT @Pm;”SENS:LIM:STAT ON” 150 OUTPUT @Pm;”STAT:OPER:PTR 4096” 160 OUTPUT @Pm;”STAT:OPER:ENAB 4096” 170 OUTPUT @Pm;”*SRE 128” 180 ! 190 ENABLE INTR 7;2 ! Enable an SRQ to cause an interrupt 200 LOOP ! Idle loop 210 ! Forever 220 END LOOP 230 ! 240 ! When a SRQ is detected , the following routine will

service it. 250 ! 260 Srq_i: ! 270 St=SPOLL(@Pm) ! Serial Poll (reads status byte) 280 IF BIT(St,7)=1 THEN ! Operation status bit set? 290 OUTPUT @Pm;”STAT:OPER?”! Yes , read register 300 ENTER @Pm;Oper ! (this also clears it) 310 OUTPUT @Pm;”STAT:OPER:ULF?” 320 ENTER @Pm;Ulf 330 IF Ulf=2 THEN PRINT “Over limit detected” 340 END IF 350 GOTO 190 ! Return to idle loop 360 END

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Power Meter Remote Operation

Status Reporting

Status Register

The Status System in the power meter is shown in Figure 1-11. The

Operation Status and Questionable Status groups are 16 bits wide, while

the Status Byte and Standard Event groups are 8 bits wide. In all 16-bit

groups, the most signiﬁcant bit (bit 15) is not used and is always set to 0.

Figure 1-11: Status System

Device Status

Condition Event Enable

Questionable Status

Condition Event Enable

Output Queue

Standard Event

Logical OR

Error/Event Queue

0 1

2 QUE MAV ESB

RQS/MSS

OPR

*STB?

Status Byte

QUE

MAV ESB

OPR

*SRE

Logical OR

Event

Enable

*ESR

*ESE

Operation Status

Logical OR

Condition Event Enable

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Status Reporting

The Status Byte

The status byte summary register reports conditions from other status registers. Query data waiting in the power meter’s output buffer is immediately reported through the “message available” bit (bit 4). Clearing an event register clears the corresponding bits in the status byte summary register. Reading all messages in the output buffer, including any pending queries, clears the message available bit.

Table 1-3: Bit Deﬁnitions - Status Byte Register

Bit

Number

0 1 Not Used (Always set to 0) 1 2 Device Status Register summary bit.

2 4 Error/Event Queue 3 8 Questionable Status Register summary bit.

4 16 Message Available

5 32 Standard Event

6 64 Request Service

7 128 Operation Status Register summary bit.

Decimal

Weight

Deﬁnition

One or more bits are set in the Device Status Register (bits must be “enabled” in enable register)

One or more bits are set in the Questionable Status Register (bits must be “enabled” in enable register).

Data is available in the power meter’s output buffer.

One or more bits are set in the Standard Event register (bits must be “enabled” in enable register).

The power meter is requesting service (serial poll).

One or more bits are set in the Operation Status Register (bits must be “enabled” in enable register).

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Status Reporting

Particular bits in the status byte register are cleared when:

• The standard event, Questionable status, operation status and device status are queried.

• The error/event queue becomes empty.

• The output queue becomes empty.

The status byte enable register (SRE, service request enable) is cleared when you:

• cycle the instrument power.

• execute a *SRE 0 command.

Using *STB? to Read the Status Byte

The *STB? (status byte query) command is similar to a serial poll except it is processed like any other power meter command. The *STB? command returns the same result as an IEEE-488 serial poll except that the request service bit (bit 6) is not cleared if a serial poll has occurred. The *STB? command is not handled automatically by the IEEE-488 bus interface hardware and the command will be executed only after previous commands have completed. Using the *STB? command does not clear the status byte summary register.

The Standard Event Register

The standard event register reports the following types of instrument events: power-on detected, command and syntax errors, command execution errors, self-test or calibration errors, query errors, or when an overlapped command completes following a *OPC command. Any or all of these conditions can be reported in the standard event summary bit through the enable register. You must write a decimal value using the *ESE (event status enable) command to set the enable register mask.

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Table 1-4: Bit Deﬁnitions - Standard Event Register

Status Reporting

Bit

Number

0 1 Operation Complete

1 2 Not Used. (Always set to 0.) 2 4 Query Error

3 8 Device Error

4 16 Execution Error

5 32 Command Error

6 64 Not Used. (Always set to 0.) 7 128 Power On

Decimal

Value

All overlapped commands following an command have been completed.

A query error occurred, refer to error numbers 410 to 440 in the User’s Guide.

A device error occurred, refer to error numbers 310 to 350 in the User’s Guide.

An execution error occurred, refer to error mumbers 211 to 241 in the User’s Guide.

A command syntax error occurred, refer to error numbers 101 to 161 in the User’s Guide.

Power has been turned off and on since the last time the event register was read or cleared.

Deﬁnition

*OPC

The standard event register is cleared when you:

• send a *CLS (clear status) command.

• query the event register using the *ESR? (event status register) command.

The standard event enable register is cleared when you:

• cycle the instrument power.

• execute a *ESE 0 command.

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Status Reporting

Questionable Status Register

The questionable status register provides information about the quality of the power meter’s measurement results. Any or all of these conditions can be reported in the questionable data summary bit through the enable register. You must write a value using the STATus:QUEStionable:ENABle command to set the enable register mask.

The questionable status model is shown in the pullout at the end of this chapter.

The following bits in these registers are used by the power meter.

Bit Number

0 to 2 - Not used

3 8 POWer Summary

4 to 7 - Not used

8 256 CALibration Summary 9 512 Power On Self Test

10 to 14 - Not Used

15 - Not used (always 0)

Decimal Weight

Deﬁnition

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The condition bits are set and cleared under the following conditions:

Bit Number Meaning EVENts Causing Bit Changes

Status Reporting

3 POWer

Summary

8 CALibration

Summary

This is a summary bit for the Questionable POWer Register.

SET:

Error -230, “Data corrupt or stale” Error -231, “Data questionable;Input Overload” Error -231, “Data questionable;Input Overload ChA” Error -231, “Data questionable;Input Overload ChB”

Error -231, “Data questionable;PLEASE ZERO” Error -231, “Data questionable;PLEASE ZERO ChA” Error -231, “Data questionable;PLEASE ZERO ChB” Error -231, ”Data questionable;Lower window log error” Error -231, ”Data questionable;Upper window log error”

1 1

CLEARED: When no errors are detected by the power meter during a measurement covering the causes given for it to set.

This is a summary bit for the Questionable CALibration Register.

SET:

These may be caused by

CALibration[1|2]:ZERO:AUTO ONCE or CALibration[1|2]:AUTO ONCE or CALibration[1|2][:ALL] or CALibration[1|2][:ALL]?.

Error -231, “Data questionable; ZERO ERROR” Error -231, “Data questionable; ZERO ERROR ChA” Error -231, “Data questionable; ZERO ERROR ChB”

1 1

Error -231, “Data questionable; CAL ERROR” Error -231, “Data questionable; CAL ERROR ChA” Error -231, “Data questionable; CAL ERROR ChB”

1 1

CLEARED: When any of the commands listed above succeed and no errors are placed on the error queue.

9 Power On

SET: This bit is set when the power on self test fails.

Self Test

CLEARED: When the power on self test passes.

1. HP EPM-442A only

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Status Reporting

Operation Status

The Operation Status group monitors conditions in the power meter’s measurement process.

The Operation status model is shown in the pullout at the end of this chapter.

The following bits in these registers are used by the power meter:

Bit Number

0 1 CALibrating Summary

1 - 3 - Not used

4 16 MEASuring Summary 5 32 Waiting for TRIGger Summary

6 - 9 - Not used

10 1024 SENSe Summary 11 2048 Lower Limit Fail Summary 12 4096 Upper Limit Fail Summary

13 to 14 - Not used

15 - Not used (always 0)

Decimal Weight

Deﬁnition

The condition bits are set and cleared under the following conditions:

Bit Number

0 CALibrating This is a summary bit for the Operation

Meaning EVENts Causing Bit Changes

CALibrating Register. SET: At beginning of zeroing (CALibration:ZERO:AUTO ONCE) and at the beginning of calibration (CALibration:AUTO

ONCE). Also for the compound command/query CALibration[:ALL]?, this bit is set at the

beginning of the zero.

CLEARED: At the end of zeroing or calibration.

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Bit Number

4 MEASuring This is a summary bit for the Operation MEASuring

5 Waiting for

10 SENSe This is a summary bit for the Operation SENSe

Meaning EVENts Causing Bit Changes

CLEARED: When the measurement is ﬁnished. This is a summary bit for the Operation TRIGger

TRIGger

CLEARED: When the power meter enters the “idle” state. Refer to Figure 1-7.

CLEARED: When the power meter is not reading data from the HP E-series power sensor EEPROM.

11 Lower

Limit Fail

12 Upper

Limit Fail

This is a summary bit for the Lower Limit Fail Register. SET: If a power measurement is made and the lower limit test fails.

CLEARED: If a power measurement is made and the lower limit test is not enabled or the test is enabled and passes.

This is a summary bit for the Upper Limit Fail Register. SET: If a power measurement is made and the upper limit test fails.

CLEARED: If a power measurement is made and the upper limit test is not enabled or the test is enabled and passes.

HP EPM-441A/442A Programming Guide 1-75

Power Meter Remote Operation

Status Reporting

Device Status Register

The device status register set contains bits which give device dependent information.

The following bits in these registers are used by the power meter:

Bit Number

Decimal Weight

Deﬁnition

0 - Not used 1 2 Channel A sensor connected 2 4 Channel B sensor connected 3 8 Channel A sensor error 4 16 Channel B sensor error 5 32 Channel A sensor Front/Rear 6 64 Channel B sensor Front/Rear

14 16384 Front Panel key press

1. HP EPM-442A only

1-76 HP EPM-441A/442A Programming Guide

Power Meter Remote Operation

Status Reporting

The condition bits are set and cleared under the following conditions:

Bit Number

1 Channel A

2 Channel B

3 Channel A

4 Channel B

Meaning EVENts Causing Bit Changes

sensor connected

error

SET: When a power sensor is connected to the Channel A input.

CLEARED: When no power sensor is connected to the Channel A input.

SET: When a power sensor is connected to the Channel B input.

CLEARED: When no power sensor is connected to the Channel B input.

SET: If the power sensor EEPROM on Channel A has failed or if there are power sensors connected to both the rear and front panel Channel A connectors.

CLEARED: In every other condition. SET: If the power sensor EEPROM on Channel B

has failed or if there are power sensors connected to both the rear and front panel Channel B connectors.

CLEARED: In every other condition.

5 Channel A

Front/Rear

6 Channel B

Front/Rear

14 Front Panel

Key Press

SET: If a power sensor is connected to the Channel A rear panel.

CLEARED: If a power sensor is connected to the Channel A front panel.

SET: If a power sensor is connected to the Channel B rear panel.

CLEARED: If a power sensor is connected to the Channel B front panel.

This is an event, and DOES NOT set the condition register. The bit will be set in the event register which will be cleared when read. Note that the transition registers are of no use for this bit.

HP EPM-441A/442A Programming Guide 1-77

Power Meter Remote Operation

Status Reporting

Using the Operation Complete Commands

The *OPC? and *OPC commands allow you to maintain synchronization between the computer and the power meter. The *OPC? query command places an ASCII character 1 into the power meter’s output queue when all pending power meter commands are complete. If your program reads this response before continuing program execution, you can ensure synchronization between one or more instruments and the computer.

The *OPC command sets bit 0 (Operation Complete) in the Standard Event Status Register when all pending power meter operations are complete. By enabling this bit to be reﬂected in the Status Register, you can ensure synchronization using the HP-IB serial poll.

Procedure

• Send a device clear message to clear the power meter’s output buffer.

• Clear the event registers with the *CLS (clear status) command.

• Enable operation complete using the *ESE 1 command (standard event register).

• Send the *OPC? (operation complete query) command and enter the result to assure synchronization.

• Send your programming command string, and place the *OPC (operation complete) command as the last command.

• Use a serial poll to check to see when bit 5 (standard event) is set in the status byte summary register. You could also conﬁgure the power meter for an SRQ interrupt by sending *SRE 32 (status byte enable register, bit 5).

1-78 HP EPM-441A/442A Programming Guide

Agilent E4418A Programming Guide

Specifications and Main Features

Frequently Asked Questions

User Manual