Agilent 54831B Programmer’s Reference

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Programmer’s Reference

Publication Number 54830-97014 March 2005

This reference applies directly to software revision code A.04.00 and later.

54830 Series Infiniium Oscilloscopes

In This Book

This book is your guide to programming the Infiniium Series Oscilloscopes. Chapters 1-5 give you an introduction to programming the oscilloscopes, along

with necessary conceptual information. These chapters describe basic program communications, interface, syntax, data types, and status reporting.

Chapter 6 shows example BASIC and C programs, and describes chunks of one program to show you some typical applications. The BASIC and C example programs are also shipped on a disk with the oscilloscope.

Chapters 7-25 describe the commands used to program the Infiniium Oscilloscopes. Each chapter describes the set of commands that belong to an individual subsystem, and explains the function of each command. These chapters include:

ACQuire

BUS MARKer

CALibration MEASure

CHANnel POD

Common Root Level

DIGital

DISK SYSTem

DISPlay TIMe Base

EXTernal Channel TRIGger

FUNCtion WAVeform

HARDcopy Waveform MEMory

HISTogram

SELFtest

Error Messages chapter describes error messages.

Contents

1 Introduction to Programming

Communicating with the Oscilloscope 1-3 Output Command 1-4 Device Address 1-4 Instructions 1-4 Instruction Header 1-4 White Space (Separator) 1-5 Braces 1-5 Ellipsis 1-5 Square Brackets 1-5 Command and Query Sources 1-5 Program Data 1-6 Header Types 1-7 Duplicate Mnemonics 1-9 Query Headers 1-10 Program Header Options 1-11 Character Program Data 1-11 Numeric Program Data 1-12 Embedded Strings 1-13 Program Message Terminator 1-13 Common Commands within a Subsystem 1-14 Selecting Multiple Subsystems 1-14 Programming Getting Started 1-14 Initialization 1-15 Example Program using HP Basic 1-16 Using the DIGITIZE Command 1-17 Receiving Information from the Oscilloscope 1-19 String Variable Example 1-20 Numeric Variable Example 1-20 Definite-Length Block Response Data 1-21 Multiple Queries 1-22 Oscilloscope Status 1-22

2 LAN and GPIB Interfaces

LAN Interface Connector 2-3 GPIB Interface Connector 2-3 Default Startup Conditions 2-4 Interface Capabilities 2-5 GPIB Command and Data Concepts 2-6 Communicating Over the GPIB Interface 2-7 Communicating Over the LAN Interface 2-8 Bus Commands 2-10

Contents-1

Contents

3 Message Communication and System Functions

Protocols 3-3

4 Status Reporting

Status Reporting Data Structures 4-5 Status Byte Register 4-8 Service Request Enable Register 4-10 Message Event Register 4-10 Trigger Event Register 4-10 Standard Event Status Register 4-11 Standard Event Status Enable Register 4-12 Operation Status Register 4-13 Operation Status Enable Register 4-14 Mask Test Event Register 4-15 Mask Test Event Enable Register 4-16 Trigger Armed Event Register 4-17 Acquisition Done Event Register 4-17 Error Queue 4-18 Output Queue 4-18 Message Queue 4-19 Clearing Registers and Queues 4-19

5 Programming Conventions

Truncation Rule 5-3 The Command Tree 5-4 Infinity Representation 5-14 Sequential and Overlapped Commands 5-14 Response Generation 5-14 EOI 5-14

6 Sample Programs

Sample Program Structure 6-3 Sample C Programs 6-4 Listings of the Sample Programs 6-18 gpibdecl.h Sample Header 6-19 srqagi.c Sample Program 6-21 learnstr.c Sample Program 6-23 sicl_IO.c Sample Program 6-27 natl_IO.c Sample Program 6-32 init.bas Sample Program 6-37 srq.bas Sample Program 6-45

Contents-2

lrn_str.bas Sample Program 6-51

7 Acquire Commands

AVERage 7-3 AVERage:COUNt 7-4 COMPlete 7-5 COMPlete:STATe 7-7 INTerpolate 7-8 MODE 7-9 POINts 7-11 POINts:AUTO 7-21 SEGMented:COUNt 7-22 SEGMented:INDex 7-23 SRATe (Sample RATe) 7-24 SRATe:AUTO 7-26

8 Bus Commands

BIT<M> 8-3 BITS 8-4 CLEar 8-5 DISPlay 8-6 LABel 8-7

Contents

9 Calibration Commands

Oscilloscope Calibration 9-3 Probe Calibration 9-4

Calibration Commands 9-5 OUTPut 9-6

SKEW 9-7 STATus? 9-8

10 Channel Commands

BWLimit 10-3 DISPlay 10-4 INPut 10-5 OFFSet 10-6 PROBe 10-7 PROBe:ATTenuation 10-9 PROBe:EADapter 10-10 PROBe:ECoupling 10-12 PROBe:EXTernal 10-14

Contents-3

Contents

PROBe:EXTernal:GAIN 10-15 PROBe:EXTernal:OFFSet 10-17 PROBe:EXTernal:UNITs 10-19 PROBe:GAIN 10-21 PROBe:ID? 10-22 PROBe:SKEW 10-24 PROBe:STYPe 10-25 RANGe 10-26 SCALe 10-27 UNITs 10-28

11 Common Commands

*CLS (Clear Status) 11-4 *ESE (Event Status Enable) 11-5 *ESR? (Event Status Register) 11-7 *IDN? (Identification Number) 11-9 *LRN? (Learn) 11-11 *OPC (Operation Complete) 11-13 *OPT? (Option) 11-14 *PSC (Power-on Status Clear) 11-15 *RCL (Recall) 11-16 *RST (Reset) 11-17 *SAV (Save) 11-18 *SRE (Service Request Enable) 11-19 *STB? (Status Byte) 11-21 *TRG (Trigger) 11-23 *TST? (Test) 11-24 *WAI (Wait) 11-25

12 Digital Commands

DISPlay 12-3 LABel 12-4 SIZE 12-5 THReshold 12-6

13 Disk Commands

CDIRectory 13-3 DELete 13-4 DIRectory? 13-5 LOAD 13-6 MDIRectory 13-7 MSTore 13-8

Contents-4

PWD? 13-12 SEGMented 13-13 SIMage 13-14 STORe 13-15

14 Display Commands

CGRade 14-3 CGRade:LEVels? 14-5 COLumn 14-7 CONNect 14-8 DATA? 14-9 DCOLor 14-10 GRATicule 14-11 LABel 14-13 LINE 14-14 PERSistence 14-15 ROW 14-16 SCOLor 14-17 STRing 14-20 TEXT 14-21

Contents

15 External Trigger Commands

BWLimit 15-3 INPut 15-4 PROBe 15-5 PROBe:ATTenuation 15-6 PROBe:EADapter 15-7 PROBe:ECoupling 15-9 PROBe:EXTernal 15-11 PROBe:EXTernal:GAIN 15-12 PROBe:EXTernal:UNITs 15-14 PROBe:GAIN 15-16 PROBe:ID? 15-17 PROBe:SKEW 15-18 RANGe 15-19 UNITs 15-20

16 Function Commands

FUNCtion<N>? 16-4 ADD 16-5 AVERage 16-6 COMMonmode 16-7

Contents-5

Contents

DIFF (Differentiate) 16-8 DISPlay 16-9 DIVide 16-10 FFT:FREQuency 16-11 FFT:RESolution? 16-12 FFT:WINDow 16-13 FFTMagnitude 16-15 FFTPhase 16-16 FFTPhase 16-17 HIGHpass 16-18 HORizontal:POSition 16-19 HORizontal:RANGe 16-20 INTegrate 16-21 INVert 16-22 LOWPass 16-23 MAGNify 16-24 MAXimum 16-25 MAXimum 16-26 MINimum 16-27 MULTiply 16-28 OFFSet 16-29 RANGe 16-30 SMOoth 16-31 SUBTract 16-32 VERSus 16-33 VERTical 16-34 VERTical:OFFSet 16-35 VERTical:RANGe 16-36

17 Hardcopy Commands

AREA 17-3 DPRinter 17-4 FACTors 17-6 IMAGe 17-7 PRINters? 17-8

18 Histogram Commands

AXIS 18-4 MODE 18-5 SCALe:SIZE 18-6 WINDow:DEFault 18-7 WINDow:SOURce 18-8

Contents-6

WINDow:X1Position | LLIMit 18-9 WINDow:X2Position | RLIMit 18-10 WINDow:Y1Position | BLIMit 18-11 WINDow:Y2Position | TLIMit 18-12

19 Marker Commands

CURSor? 19-3 MEASurement:READout 19-4 MODE 19-5 TDELta? 19-6 TSTArt 19-7 TSTOp 19-9 VDELta? 19-11 VSTArt 19-12 VSTOp 19-14 X1Position 19-16 X2Position 19-17 X1Y1source 19-18 X2Y2source 19-19 XDELta? 19-20 Y1Position 19-21 Y2Position 19-22 YDELta? 19-23

Contents

20 Mask Test Commands

ALIGn 20-4 AlignFIT 20-5 AMASk:CREate 20-7 AMASk:SOURce 20-8 AMASk:[SAVE | STORe] 20-9 AMASk:UNITs 20-10 AMASk:XDELta 20-11 AMASk:YDELta 20-13 AUTO 20-15 AVERage 20-16 AVERage:COUNt 20-17 COUNt:FAILures? 20-18 COUNt:FWAVeforms? 20-19 COUNt:WAVeforms? 20-20 DELete 20-21 ENABle 20-22 FOLDing 20-23

Contents-7

Contents

FOLDing:BITS 20-24 HAMPlitude 20-25 IMPedance 20-26 INVert 20-28 LAMPlitude 20-29 LOAD 20-30 NREGions? 20-31 PROBe:IMPedance? 20-32 RUMode 20-33 RUMode:SOFailure 20-35 SCALe:BIND 20-36 SCALe:X1 20-37 SCALe:XDELta 20-38 SCALe:Y1 20-40 SCALe:Y2 20-41 SOURce 20-42 STARt | STOP 20-43 STIMe 20-44 TITLe? 20-45 TRIGger:SOURce 20-46

21 Measure Commands

AREA 21-7 CGRade:CROSsing 21-8 CGRade:DCDistortion 21-9 CGRade:EHEight 21-10 CGRade:EWIDth 21-11 CGRade:JITTer 21-12 CGRade:QFACtor 21-13 CLEar 21-14 CLOCk 21-15 CLOCk:METHod 21-16 CLOCk::VERTical 21-18 CLOCk::VERTical:OFFSet 21-19 CLOCk:VERTical:RANGe 21-20 CTCDutycycle 21-21 CTCJitter 21-23 CTCNwidth 21-25 CTCPwidth 21-26 DATarate 21-27 DEFine 21-29 DELTatime 21-34 DUTYcycle 21-36

Contents-8

FALLtime 21-38 FFT:DFRequency 21-40 FFT:DMAGnitude 21-41 FFT:FREQuency 21-42 FFT:MAGNitude 21-43 FFT:PEAK1 21-44 FFT:PEAK2 21-45 FFT:THReshold 21-46 FREQuency 21-47 HISTogram:HITS 21-49 HISTogram:M1S 21-51 HISTogram:M2S 21-53 HISTogram:M3S 21-55 HISTogram:MAX? 21-57 HISTogram:MEAN? 21-58 HISTogram:MEDian? 21-59 HISTogram:MIN? 21-60 HISTogram:PEAK? 21-61 HISTogram:PP? 21-62 HISTogram:STDDev? 21-63 HOLDtime 21-64 JITTer:MEASurement 21-66 JITTer:SPECtrum 21-67 JITTer:SPECtrum:HORizontal 21-68 JITTer:SPECtrum:HORizontal:POSition 21-69 JITTer:SPECtrum:HORizontal:RANGe 21-71 JITTer:SPECtrum:VERTical 21-72 JITTer:SPECtrum:VERTical:OFFSet 21-73 JITTer:SPECtrum:VERTical:RANGe 21-74 JITTer:SPECtrum:WINDow 21-75 JITTer:STATistics 21-76 JITTer:TRENd 21-77 JITTer:TRENd:SMOoth 21-78 JITTer:TREND:SMOoth:POINts 21-79 JITTer:TRENd:VERTical 21-80 JITTer:TRENd:VERTical:OFFSet 21-81 JITTer:TRENd:VERTical:RANGe 21-82 NCJitter 21-83 NWIDth 21-85 OVERshoot 21-87 PERiod 21-89 PHASe 21-91 PREShoot 21-93

Contents

Contents-9

Contents

PWIDth 21-95 RESults? 21-97 RISetime 21-100 SCRatch 21-102 SENDvalid 21-103 SETuptime 21-104 SOURce 21-106 STATistics 21-107 TEDGe 21-108 TIEClock2 21-110 TIEData 21-112 TMAX 21-114 TMIN 21-115 TVOLt 21-116 UNITinterval 21-118 VAMPlitude 21-120 VAVerage 21-121 VBASe 21-123 VLOWer 21-125 VMAX 21-126 VMIDdle 21-128 VMIN 21-129 VPP 21-131 VRMS 21-133 VTIMe 21-135 VTOP 21-136 VUPPer 21-138

22 Pod Commands

DISPlay 22-3 THReshold 22-4 PSKew 22-5

23 Root Level Commands

ADER? (Acquisition Done Event Register) 23-4 AER? (Arm Event Register) 23-5 ATER? (Auto Trigger Event Register) 23-6 AUToscale 23-7 BLANk 23-8 CDISplay 23-9 DIGitize 23-10 DISable 23-12

Contents-10

ENABle 23-13 MTEE 23-14 MTER? 23-15 MODel? 23-16 OPEE 23-17 OPER? 23-18 OVLEnable 23-19 OVLRegister? 23-20 PRINt 23-21 RECall:SETup 23-22 RUN 23-23 SERial (Serial Number) 23-24 SINGle 23-25 STATus? 23-26 STOP 23-27 STORe:SETup 23-28 STORe:WAVeform 23-29 TER? (Trigger Event Register) 23-30 VIEW 23-31

Contents

24 Self-Test Commands

AttenSET? 24-3 CANCel 24-4 SCOPETEST 24-5

25 System Commands

DATE 25-3 DEBug 25-4 DSP 25-6 ERRor? 25-7 HEADer 25-8 LOCK 25-10 LONGform 25-11 SETup 25-13 TIME 25-15

26 Time Base Commands

POSition 26-3 RANGe 26-4 REFerence 26-5 ROLL:ENABLE 26-6 SCALe 26-7

Contents-11

Contents

VIEW 26-8 WINDow:DELay 26-9 WINDow:POSition 26-11 WINDow:RANGe 26-12 WINDow:SCALe 26-13

27 Trigger Commands

Organization of Trigger Modes and Commands 27-5

Summary of Trigger Modes and Commands 27-6 Trigger Modes 27-8

HOLDoff 27-9 HTHReshold 27-10 HYSTeresis 27-11 LEVel 27-12 LTHReshold 27-13 SWEep 27-14

Edge Trigger Mode and Commands 27-15 EDGE:COUPling 27-17

EDGE:SLOPe 27-18 EDGE:SOURce 27-19

Glitch Trigger Mode and Commands 27-20 GLITch:POLarity 27-22

GLITch:SOURce 27-23 GLITch:WIDTh 27-24

Advanced COMM Trigger Mode and Commands 27-25 COMM:BWIDth 27-26

COMM:ENCode 27-27 COMM:LEVel 27-28 COMM:PATTern 27-29 COMM:POLarity 27-30 COMM:SOURce 27-31

Advanced Pattern Trigger Mode and Commands 27-32 PATTern:CONDition 27-34

PATTern:LOGic 27-35 :PATTern:THReshold:LEVel 27-36 :PATTern:THReshold:POD<N> 27-37

Contents-12

Advanced State Trigger Mode and Commands 27-38 STATe:CLOCk 27-40

STATe:LOGic 27-41 STATe:LTYPe 27-42 STATe:SLOPe 27-43 :STATe:THReshold:LEVel 27-44

Advanced Delay By Event Mode and Commands 27-45 EDLY:ARM:SOURce 27-47

EDLY:ARM:SLOPe 27-48 EDLY:EVENt:DELay 27-49 EDLY:EVENt:SOURce 27-50 EDLY:EVENt:SLOPe 27-51 EDLY:TRIGger:SOURce 27-52 EDLY:TRIGger:SLOPe 27-53

Advanced Delay By Time Mode and Commands 27-54 TDLY:ARM:SOURce 27-56

TDLY:ARM:SLOPe 27-57 TDLY:DELay 27-58 TDLY:TRIGger:SOURce 27-59 TDLY:TRIGger:SLOPe 27-60

Contents

Advanced Standard TV Mode and Commands 27-61 STV:FIELd 27-63

STV:LINE 27-64 STV:SOURce 27-65 STV:SPOLarity 27-66

Advanced User Defined TV Mode and Commands 27-67 UDTV:ENUMber 27-69

UDTV:PGTHan 27-70 UDTV:POLarity 27-71 UDTV:SOURce 27-72

Advanced Trigger Violation Modes 27-73 VIOLation:MODE 27-74

Pulse Width Violation Mode and Commands 27-75 VIOLation:PWIDth:DIRection 27-77

VIOLation:PWIDth:POLarity 27-78 VIOLation:PWIDth:SOURce 27-79

Contents-13

Contents

VIOLation:PWIDth:WIDTh 27-80

Setup Violation Mode and Commands 27-81 VIOLation:SETup:MODE 27-84

VIOLation:SETup:SETup:CSOurce 27-85 VIOLation:SETup:SETup:CSOurce:LEVel 27-86 VIOLation:SETup:SETup:CSOurce:EDGE 27-87 VIOLation:SETup:SETup:DSOurce 27-88 VIOLation:SETup:SETup:DSOurce:HTHReshold 27-89 VIOLation:SETup:SETup:DSOurce:LTHReshold 27-90 VIOLation:SETup:SETup:TIME 27-91 VIOLation:SETup:HOLD:CSOurce 27-92 VIOLation:SETup:HOLD:CSOurce:LEVel 27-93 VIOLation:SETup:HOLD:CSOurce:EDGE 27-94 VIOLation:SETup:HOLD:DSOurce 27-95 VIOLation:SETup:HOLD:DSOurce:HTHReshold 27-96 VIOLation:SETup:HOLD:DSOurce:LTHReshold 27-97 VIOLation:SETup:HOLD:TIME 27-98 VIOLation:SETup:SHOLd:CSOurce 27-99 VIOLation:SETup:SHOLd:CSOurce:LEVel 27-100 VIOLation:SETup:SHOLd:CSOurce:EDGE 27-101 VIOLation:SETup:SHOLd:DSOurce 27-102 VIOLation:SETup:SHOLd:DSOurce:HTHReshold 27-103 VIOLation:SETup:SHOLd:DSOurce:LTHReshold 27-104 VIOLation:SETup:SHOLd:SetupTIMe (STIMe) 27-105 VIOLation:SETup:SHOLd:HoldTIMe (HTIMe) 27-106

Transition Violation Mode 27-107 VIOLation:TRANsition 27-109

VIOLation:TRANsition:SOURce 27-110 VIOLation:TRANsition:SOURce:HTHReshold 27-111 VIOLation:TRANsition:SOURce:LTHReshold 27-112 VIOLation:TRANsition:TYPE 27-113

28 Waveform Commands

BANDpass? 28-5 BYTeorder 28-6 COMPlete? 28-7 COUNt? 28-8 COUPling? 28-9 DATA? 28-10 DATA? Example for Analog Channels 28-12 DATA? Example for Digital Channels 28-26

Contents-14

FORMat 28-41 POINts? 28-44 PREamble 28-45 SEGMented:COUNt? 28-51 SEGMented:TTAG? 28-52 SOURce 28-53 TYPE? 28-55 VIEW 28-57 XDISplay? 28-59 XINCrement? 28-60 XORigin? 28-61 XRANge? 28-62 XREFerence? 28-63 XUNits? 28-64 YDISplay? 28-65 YINCrement? 28-66 YORigin? 28-67 YRANge? 28-68 YREFerence? 28-69 YUNits? 28-70

Contents

29 Waveform Memory Commands

DISPlay 29-3 LOAD 29-4 SAVE 29-5 XOFFset 29-6 XRANge 29-7 YOFFset 29-8 YRANge 29-9

30 Error Messages

Error Queue 30-3 Error Numbers 30-4 Command Error 30-5 Execution Error 30-6 Device- or Oscilloscope-Specific Error 30-7 Query Error 30-8 List of Error Messages 30-9

Contents-15

Contents-16

Introduction to Programming

This chapter introduces the basics for remote programming of an oscilloscope. The programming commands in this manual conform to the IEEE 488.2 Standard Digital Interface for Programmable Instrumentation. The programming commands provide the means of remote control.

Basic operations that you can do with a computer and an oscilloscope include:

• Set up the oscilloscope.

• Make measurements.

• Get data (waveform, measurements, and configuration) from the oscilloscope.

• Send information, such as waveforms and configurations, to the oscilloscope.

You can accomplish other tasks by combining these functions.

Example Programs are Written in HP BASIC and C

The programming examples for individual commands in this manual are written in HP BASIC and C.

1-2

Introduction to Programming

Communicating with the Oscilloscope

Computers communicate with the oscilloscope by sending and receiving messages over a remote interface, such as a GPIB card or a Local Area Network (LAN) card. Commands for programming normally appear as ASCII character strings embedded inside the output statements of a “host” language available on your computer. The input commands of the host language are used to read responses from the oscilloscope.

For example, HP BASIC uses the OUTPUT statement for sending commands and queries. After a query is sent, the response is usually read using the HP BASIC ENTER statement. The ENTER statement passes the value across the bus to the computer and places it in the designated variable.

For the GPIB interface, messages are placed on the bus using an output command and passing the device address, program message, and a terminator. Passing the device address ensures that the program message is sent to the correct GPIB interface and GPIB device.

The following HP BASIC OUTPUT statement sends a command that sets the channel 1 scale value to 500 mV:

OUTPUT <device address> ;":CHANNEL1:SCALE 500E3"<terminator>

The device address represents the address of the device being programmed. Each of the other parts of the above statement are explained on the following pages.

Use the Suffix Multiplier Instead

Using "mV" or "V" following the numeric voltage value in some commands will cause Error 138 - Suffix not allowed. Instead, use the convention for the suffix multiplier as described in chapter 3, "Message Communication and System Functions."

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Introduction to Programming

Output Command

The output command depends entirely on the programming language. Throughout this book, HP BASIC and ANSI C are used in the examples of individual commands. If you are using other languages, you will need to find the equivalents of HP BASIC commands like OUTPUT, ENTER, and CLEAR, to convert the examples.

Device Address

The location where the device address must be specified depends on the programming language you are using. In some languages, it may be specified outside the OUTPUT command. In HP BASIC, it is always specified after the keyword, OUTPUT. The examples in this manual assume that the oscilloscope and interface card are at GPIB device address 707. When writing programs, the device address varies according to how the bus is configured.

Instructions

Instructions, both commands and queries, normally appear as strings embedded in a statement of your host language, such as BASIC, Pascal, or C. The only time a parameter is not meant to be expressed as a string is when the instruction's syntax definition specifies <block data>, such as HP BASIC’s "learnstring" command. There are only a few instructions that use block data.

Instructions are composed of two main parts:

• The header, which specifies the command or query to be sent.

• The program data, which provides additional information to clarify the meaning of the instruction.

Instruction Header

The instruction header is one or more command mnemonics separated by colons (:). They represent the operation to be performed by the oscilloscope. See the “Programming Conventions” chapter for more information.

Queries are formed by adding a question mark (?) to the end of the header. Many instructions can be used as either commands or queries, depending on whether or not you include the question mark. The command and query forms of an instruction usually have different program data. Many queries do not use any program data.

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Introduction to Programming

White Space (Separator)

White space is used to separate the instruction header from the program data. If the instruction does not require any program data parameters, you do not need to include any white space. In this manual, white space is defined as one or more spaces. ASCII defines a space to be character 32 in decimal.

Braces

When several items are enclosed by braces, { }, only one of these elements may be selected. Vertical line ( | ) indicates "or". For example, {ON | OFF} indicates that only ON or OFF may be selected, not both.

Ellipsis

... An ellipsis (trailing dots) indicates that the preceding element may be repeated one or more times.

Square Brackets

Items enclosed in square brackets, [ ], are optional.

Command and Query Sources

Many commands and queries require that a source be specified. Depending on the command or query and the model number of Infiniium oscilloscope being used, some of the sources are not available. The following is a list of sources:

CHANnel1 FUNCtion1 WMEMory1

CHANnel2 FUNCtion2 WMEMory2

CHANnel3 FUNCtion3 WMEMory3

CHANnel4 FUNCtion4 WMEMory4

DIGital0 DIGital1 DIGital2 DIGital3

DIGital4 DIGital5 DIGital6 DIGital7

DIGital8 DIGital9 DIGital10 DIGital11

DIGital12 DIGital13 DIGital14 DIGital15

CLOCk MTRend MSPectrum HISTogram

1-5

Introduction to Programming

Program Data

Program data is used to clarify the meaning of the command or query. It provides necessary information, such as whether a function should be on or off, or which waveform is to be displayed. Each instruction’s syntax definition shows the program data and the values they accept.

When there is more than one data parameter, they are separated by commas (,). You can add spaces around the commas to improve readability.

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Introduction to Programming

Header Types

There are three types of headers:

• Simple Command headers

• Compound Command headers

• Common Command headers

Simple Command Header

Simple command headers contain a single mnemonic. AUTOSCALE and DIGITIZE are examples of simple command headers typically used in this oscilloscope. The syntax is:

OUTPUT 707;”:AUTOSCALE”

When program data must be included with the simple command header (for example, :DIGITIZE CHAN1), white space is added to separate the data from the header. The syntax is:

OUTPUT 707;”:DIGITIZE CHANNEL1,FUNCTION2”

Compound Command Header

Compound command headers are a combination of two program mnemonics. The first mnemonic selects the subsystem, and the second mnemonic selects the function within that subsystem. The mnemonics within the compound message are separated by colons. For example:

To execute a single function within a subsystem:

:<subsystem>:<function><separator><program data><terminator>

For example:

OUTPUT 707;”:CHANNEL1:BWLIMIT ON”

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Introduction to Programming

Header Types

Combining Commands in the Same Subsystem

To execute more than one command within the same subsystem, use a semicolon (;) to separate the commands:

:<subsystem>:<command><separator><data>;<command><separator> <data><terminator>

For example:

:CHANNEL1:INPUT DC;BWLIMIT ON

Common Command Header

Common command headers, such as clear status, control the IEEE 488.2 functions within the oscilloscope. The syntax is:

*<command header><terminator>

No space or separator is allowed between the asterisk (*) and the command header. *CLS is an example of a common command header.

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Introduction to Programming

Duplicate Mnemonics

Identical function mnemonics can be used for more than one subsystem. For example, you can use the function mnemonic RANGE to change both the vertical range and horizontal range:

To set the vertical range of channel 1 to 0.4 volts full scale:

:CHANNEL1:RANGE .4

To set the horizontal time base to 1 second full scale:

:TIMEBASE:RANGE 1

In these examples, CHANNEL1 and TIMEBASE are subsystem selectors, and determine the range type being modified.

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Introduction to Programming

Query Headers

A command header immediately followed by a question mark (?) is a query. After receiving a query, the oscilloscope interrogates the requested subsystem and places the answer in its output queue. The answer remains in the output queue until it is read or until another command is issued. When read, the answer is transmitted across the bus to the designated listener (typically a computer). For example, the query:

:TIMEBASE:RANGE?

places the current time base setting in the output queue. In HP BASIC, the computer input statement:

ENTER < device address > ;Range

passes the value across the bus to the computer and places it in the variable Range.

You can use queries to find out how the oscilloscope is currently configured and to get results of measurements made by the oscilloscope. For example, the command:

:MEASURE:RISETIME?

tells the oscilloscope to measure the rise time of your waveform and place the result in the output queue.

The output queue must be read before the next program message is sent. For example, when you send the query :MEASURE:RISETIME?, you must follow it with an input statement. In HP BASIC, this is usually done with an ENTER statement immediately followed by a variable name. This statement reads the result of the query and places the result in a specified variable.

Handle Queries Properly

If you send another command or query before reading the result of a query, the output buffer is cleared and the current response is lost. This also generates a queryinterrupted error in the error queue. If you execute an input statement before you send a query, it will cause the computer to wait indefinitely.

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Introduction to Programming

Program Header Options

You can send program headers using any combination of uppercase or lowercase ASCII characters. Oscilloscope responses, however, are always returned in uppercase.

You may send program command and query headers in either long form (complete spelling), short form (abbreviated spelling), or any combination of long form and short form. For example:

:TIMEBASE:DELAY 1E-6 is the long form. :TIM:DEL 1E-6 is the short form.

Using Long Form or Short Form

Programs written in long form are easily read and are almost self-documenting. The short form syntax conserves the amount of computer memory needed for program storage and reduces I/O activity.

The rules for the short form syntax are described in the chapter, “Programming Conventions.”

Character Program Data

Character program data is used to convey parameter information as alpha or alphanumeric strings. For example, the :TIMEBASE:REFERENCE command can be set to left, center, or right. The character program data in this case may be LEFT, CENTER, or RIGHT. The command :TIMEBASE:REFERENCE RIGHT sets the time base reference to right.

The available mnemonics for character program data are always included with the instruction's syntax definition. You may send either the long form of commands, or the short form (if one exists). You may mix uppercase and lowercase letters freely. When receiving responses, uppercase letters are used exclusively.

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Introduction to Programming

Numeric Program Data

Some command headers require program data to be expressed numerically. For example, :TIMEBASE:RANGE requires the desired full-scale range to be expressed numerically.

For numeric program data, you can use exponential notation or suffix multipliers to indicate the numeric value. The following numbers are all equal:

28 = 0.28E2 = 280E-1 = 28000m = 0.028K = 28E-3K When a syntax definition specifies that a number is an integer, it means that the

number should be whole. Any fractional part is ignored and truncated. Numeric data parameters that accept fractional values are called real numbers. For more information see the chapter, “Interface Functions.”

All numbers are expected to be strings of ASCII characters.

• When sending the number 9, you would send a byte representing the

ASCII code for the character “9” (which is 57).

• A three-digit number like 102 would take up three bytes (ASCII codes 49,

48, and 50). The number of bytes is figured automatically when you include the entire instruction in a string.

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Introduction to Programming

Embedded Strings

Embedded strings contain groups of alphanumeric characters which are treated as a unit of data by the oscilloscope. An example of this is the line of text written to the advisory line of the oscilloscope with the :SYSTEM:DSP command:

:SYSTEM:DSP ""This is a message.""

You may delimit embedded strings with either single (’) or double (") quotation marks. These strings are case-sensitive, and spaces are also legal characters.

Program Message Terminator

The program instructions within a data message are executed after the program message terminator is received. The terminator may be either an NL (New Line) character, an EOI (End-Or-Identify) asserted in the GPIB interface, or a combination of the two. Asserting the EOI sets the EOI control line low on the last byte of the data message. The NL character is an ASCII linefeed (decimal

10).

New Line Terminator Functions Like EOS and EOT

The NL (New Line) terminator has the same function as an EOS (End Of String) and EOT (End Of Text) terminator.

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Introduction to Programming

Common Commands within a Subsystem

Common commands can be received and processed by the oscilloscope whether they are sent over the bus as separate program messages or within other program messages. If you have selected a subsystem, and a common command is received by the oscilloscope, the oscilloscope remains in the selected subsystem. For example, if the program message

":ACQUIRE:AVERAGE ON;*CLS;COUNT 1024"

is received by the oscilloscope, the oscilloscope turns averaging on, then clears the status information without leaving the selected subsystem.

If some other type of command is received within a program message, you must re-enter the original subsystem after the command. For example, the program message

":ACQUIRE:AVERAGE ON;:AUTOSCALE;:ACQUIRE:AVERAGE:COUNT 1024"

turns averaging on, completes the autoscale operation, then sets the acquire average count. Here, :ACQUIRE must be sent again after AUTOSCALE to reenter the ACQUIRE subsystem and set the count.

Selecting Multiple Subsystems

You can send multiple program commands and program queries for different subsystems on the same line by separating each command with a semicolon. The colon following the semicolon lets you enter a new subsystem. For example:

:CHANNEL1:RANGE 0.4;:TIMEBASE:RANGE 1

You can Combine Compound and Simple Commands

Multiple program commands may be any combination of compound and simple commands.

Programming Getting Started

The remainder of this chapter explains how to set up the oscilloscope, how to retrieve setup information and measurement results, how to digitize a waveform, and how to pass data to the computer. The chapter, “Measure Commands” describes sending measurement data to the oscilloscope.

1-14

Introduction to Programming

Initialization

To make sure the bus and all appropriate interfaces are in a known state, begin every program with an initialization statement. For example, HP BASIC provides a CLEAR command which clears the interface buffer:

CLEAR 707 ! initializes the interface of the oscilloscope

When you are using GPIB, CLEAR also resets the oscilloscope’s parser. The parser is the program that reads in the instructions you send.

After clearing the interface, initialize the oscilloscope to a preset state:

OUTPUT 707;"*RST" ! initializes the oscilloscope to a preset state

Initializing the Oscilloscope

The commands and syntax for initializing the oscilloscope are discussed in the chapter, “Common Commands.” Refer to your GPIB manual and programming language reference manual for information on initializing the interface.

Autoscale

The AUTOSCALE feature of Agilent Technologies digitizing oscilloscopes performs a very useful function on unknown waveforms by automatically setting up the vertical channel, time base, and trigger level of the oscilloscope.

The syntax for the autoscale function is:

:AUTOSCALE<terminator>

Setting Up the Oscilloscope

A typical oscilloscope setup configures the vertical range and offset voltage, the horizontal range, delay time, delay reference, trigger mode, trigger level, and slope.

A typical example of the commands sent to the oscilloscope are:

:CHANNEL1:PROBE 10; RANGE 16;OFFSET 1.00<terminator> :SYSTEM:HEADER OFF<terminator> :TIMEBASE:RANGE 1E-3;DELAY 100E-6<terminator>

This example sets the time base at 1 ms full-scale (100 µs/div), with delay of 100 µs. Vertical is set to 16 V full-scale (2 V/div), with center of screen at 1 V, and probe attenuation of 10.

1-15

Introduction to Programming

Example Program using HP Basic

This program demonstrates the basic command structure used to program the oscilloscope.

10 CLEAR 707! Initialize oscilloscope interface 20 OUTPUT 707;"*RST"!Initialize oscilloscope to preset state 30 OUTPUT 707;":TIMEBASE:RANGE 5E-4"! Time base to 500 us full scale 40 OUTPUT 707;":TIMEBASE:DELAY 0"! Delay to zero 50 OUTPUT 707;":TIMEBASE:REFERENCE CENTER"! Display reference at center 60 OUTPUT 707;":CHANNEL1:PROBE 10"! Probe attenuation to 10:1 70 OUTPUT 707;":CHANNEL1:RANGE 1.6"! Vertical range to 1.6 V full scale 80 OUTPUT 707;":CHANNEL1:OFFSET -.4"! Offset to -0.4 90 OUTPUT 707;":CHANNEL1:INPUT DC"! Coupling to DC 100 OUTPUT 707;":TRIGGER:MODE EDGE"! Edge triggering 110 OUTPUT 707;":TRIGGER:LEVEL CHAN1,-.4"! Trigger level to -0.4 120 OUTPUT 707;":TRIGGER:SLOPE POSITIVE"! Trigger on positive slope 125 OUTPUT 707;":SYSTEM:HEADER OFF<terminator> 130 OUTPUT 707;":ACQUIRE:MODE RTIME"! Normal acquisition 140 OUTPUT 707;":DISPLAY:GRATICULE FRAME"! Grid off 150 END

Overview of the Program

• Line 10 initializes the oscilloscope interface to a known state.

• Line 20 initializes the oscilloscope to a preset state.

• Lines 30 through 50 set the time base, the horizontal time at 500 µs full scale, and 0 s of delay referenced at the center of the graticule.

• Lines 60 through 90 set 10:1 probe attenuation, set the vertical range to

1.6 volts full scale, center screen at −0.4 volts, and select DC 1 Mohm impedance coupling.

• Lines 100 through 120 configure the oscilloscope to trigger at −0.4 volts with positive edge triggering.

• Line 125 turns system headers off.

• Line 130 configures the oscilloscope for real time acquisition.

• Line 140 turns the grid off.

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Introduction to Programming

Using the DIGITIZE Command

The DIGITIZE command is a macro that captures data using the acquisition (ACQUIRE) subsystem. When the digitize process is complete, the acquisition is stopped. You can measure the captured data by using the oscilloscope or by transferring the data to a computer for further analysis. The captured data consists of two parts: the preamble and the waveform data record.

After changing the oscilloscope con figuration, the waveform buffers are clear ed. Before doing a measurement, you should send the DIGITIZE command to ensure new data has been collected.

You can send the DIGITIZE command with no parameters for a higher throughput. Refer to the DIGITIZE command in the chapter, “Root Level Commands” for details.

When the DIGITIZE command is sent to an oscilloscope, the specified channel’s waveform is digitized using the current ACQUIRE parameters. Before sending the :WAVEFORM:DATA? query to download waveform data to your computer, you should specify the WAVEFORM parameters.

The number of data points comprising a waveform varies according to the number requested in the ACQUIRE subsystem. The ACQUIRE subsystem determines the number of data points, type of acquisition, and number of averages used by the DIGITIZE command. This lets you specify exactly what the digitized information contains. The following program example shows a typical setup:

OUTPUT 707;":SYSTEM:HEADER OFF<terminator> OUTPUT 707;":ACQUIRE:MODE RTIME"<terminator> OUTPUT 707;":ACQUIRE:COMPLETE 100"<terminator> OUTPUT 707;":WAVEFORM:SOURCE CHANNEL1"<terminator> OUTPUT 707;":WAVEFORM:FORMAT BYTE"<terminator> OUTPUT 707;":ACQUIRE:COUNT 8"<terminator> OUTPUT 707;":ACQUIRE:POINTS 500"<terminator> OUTPUT 707;":DIGITIZE CHANNEL1"<terminator> OUTPUT 707;":WAVEFORM:DATA?"<terminator>

This setup places the oscilloscope into the real time sampling mode using eight averages. This means that when the DIGITIZE command is received, the command will execute until the waveform has been averaged at least eight times.

After receiving the :WAVEFORM:DATA? query, the oscilloscope will start downloading the waveform information.

Digitized waveforms are passed from the oscilloscope to the computer by sending a numerical representation of each digitized point. The format of the numerical representation is controlled by using the :WAVEFORM:FORMAT command and may be selected as BYTE, WORD, or ASCII.

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Introduction to Programming

Using the DIGITIZE Command

The easiest method of receiving a digitized waveform depends on data structures, available formatting, and I/O capabilities. You must convert the data values to determine the voltage value of each point. These data values are passed starting with the left most point on the oscilloscope’s display. For more information, refer to the chapter, “Waveform Commands.”

When using GPIB, you may abort a digitize operation by sending a Device Clear over the bus (for example, CLEAR 707).

1-18

Introduction to Programming

Receiving Information from the Oscilloscope

After receiving a query (a command header followed by a question mark), the oscilloscope places the answer in its output queue. The answer remains in the output queue until it is read or until another command is issued. When read, the answer is transmitted across the interface to the computer. The input statement for receiving a response message from an oscilloscope’s output queue typically has two parameters; the device address and a format specification for handling the response message. For example, to read the result of the query command :CHANNEL1:INPUT? you would execute the HP BASIC statement:

ENTER <device address> ;Setting$

This would enter the current setting for the channel 1 coupling in the string variable Setting$. The device address parameter represents the address of the oscilloscope.

All results for queries sent in a program message must be read before another program message is sent. For example, when you send the query :MEASURE:RISETIME?, you must follow that query with an input statement. In HP BASIC, this is usually done with an ENTER statement.

Handle Queries Properly

If you send an other command or que ry before reading the result of a q uery, the output buffer will be cleared and the current response will be lost. This will also generate a query-interrupted error in the error queue. If you execute an input statement before you send a query, it will cause the computer to wait indefinitely.

The format specification for handling response messages depends on both the computer and the programming language.

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Introduction to Programming

String Variable Example

The output of the oscilloscope may be numeric or character data depending on what is queried. Refer to the specific commands for the formats and types of data returned from queries.

For the example programs, assume that the device being programmed is at device address 707. The actual address depends on how you have configured the bus for your own application.

In HP BASIC 5.0, string variables are case-sensitive, and must be expressed exactly the same each time they are used. This example shows the data being returned to a string variable:

10 DIM Rang$[30] 20 OUTPUT 707;":CHANNEL1:RANGE?" 30 ENTER 707;Rang$ 40 PRINT Rang$ 50 END

After running this program, the computer displays: +8.00000E-01

Numeric Variable Example

This example shows the data being returned to a numeric variable:

10 OUTPUT 707;":CHANNEL1:RANGE?" 20 ENTER 707;Rang 30 PRINT Rang 40 END

After running this program, the computer displays: .8

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Introduction to Programming

Definite-Length Block Response Data

Definite-length block response data allows any type of device-dependent data to be transmitted over the system interface as a series of 8-bit binary data bytes. This is particularly useful for sending large quantities of data or 8-bit extended ASCII codes. The syntax is a pound sign ( # ) followed by a non-zero digit representing the number of digits in the decimal integer. After the non-zero digit is the decimal integer that states the number of 8-bit data bytes being sent. This is followed by the actual data.

For example, for transmitting 4000 bytes of data, the syntax would be:

#44000 <4000 bytes of data> <terminator>

The lifetimes “4” represents the number of digits in the number of bytes, and “4000” represents the number of bytes to be transmitted.

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Introduction to Programming

Multiple Queries

You can send multiple queries to the oscilloscope within a single program message, but you must also read them back within a single program message. This can be accomplished by either reading them back into a string variable or into multiple numeric variables. For example, you could read the result of the query :TIMEBASE:RANGE?;DELAY? into the string variable Results$ with the command:

ENTER 707;Results$

When you read the result of multiple queries into string variables, each response is separated by a semicolon. For example, the response of the query :TIMEBASE:RANGE?;DELAY? would be:

<range_value>;<delay_value>

Use the following program message to read the query :TIMEBASE:RANGE?;DELAY? into multiple numeric variables:

ENTER 707;Result1,Result2

Oscilloscope Status

Status registers track the current status of the oscilloscope. By checking the oscilloscope status, you can find out whether an operation has completed and is receiving triggers. The chapter, “Status Reporting” explains how to check the status of the oscilloscope.

1-22

LAN and GPIB Interfaces

There are two types of interfaces that can be used to remotely program the Infiniium oscilloscope: Local Area Network (LAN) interface and GPIB interface.

2-2

LAN and GPIB Interfaces

LAN Interface Connector

The oscilloscope is equiped with a LAN interface RJ-45 connector on the rear panel. This allows direct connect to your network. However, before you can use the LAN interface to program the oscilloscope, the network properties must be configured. Unless you are a Network Administrator, you should contact your Network Administrator to add the appropriate client, protocols, and configuration information for your LAN. This information is different for every company.

GPIB Interface Connector

The oscilloscope is equipped with a GPIB interface connector on the rear panel. This allows direct connection to a GPIB equipped computer. You can connect an external GPIB compatible device to the oscilloscope by installing a GPIB cable between the two units. Finger tighten the captive screws on both ends of the GPIB cable to avoid accidentally disconnecting the cable during operation.

A maximum of fifteen GPIB compatible instruments (including a computer) can be interconnected in a system by stacking connectors. This allows the oscilloscopes to be connected in virtually any configuration, as long as there is a path from the computer to every device operating on the bus.

CAUTION Avoid stacking more than three or four cables on any one connector. Multiple

connectors produce leverage that can damage a connector mounting.

2-3

LAN and GPIB Interfaces

Default Startup Conditions

The following default conditions are established during power-up:

• The Request Service (RQS) bit in the status byte register is set to zero.

• All of the event registers are cleared.

• The Standard Event Status Enable Register is set to 0xFF hex.

• Service Request Enable Register is set to 0x80 hex.

• The Operation Status Enable Register is set to 0xFFFF hex.

• The Overload Event Enable Register is set to 0xFF hex.

• The Mask Test Event Enable Register is set to 0xFF hex.

You can change the default conditions using the *PSC command with a parameter of 1 (one). When set to 1, the Standard Event Status Enable Register is set 0x00 hex and the Service Request Enable Register is set to 0x00 hex. This prevents the Power On (PON) event from setting the SRQ interrupt when the oscilloscope is ready to receive commands.

2-4

Interface Capabilities

The interface capabilities of this oscilloscope, as defined by IEEE 488.1 and IEEE 488.2, are listed in Table 2-1.

Table 2-1 Interface Capabilities

Code Interface Function Capability

SH1 Source Handshake Full Capability

AH1 Acceptor Handshake Full Capability

T5 Talker Basic Talker/Serial Poll/Talk Only Mode/

L4 Listener Basic Listener/

SR1 Service Request Full Capability

RL1 Remote Local Complete Capability

PP0 Parallel Poll No Capability

DC1 Device Clear Full Capability

DT1 Device Trigger Full Capability

C0 Computer No Capability

E2 Driver Electronics Tri State (1 MB/SEC MAX)

LAN and GPIB Interfaces

Interface Capabilities

Unaddress if Listen Address (MLA)

Unaddresses if Talk Address (MTA)

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LAN and GPIB Interfaces

GPIB Command and Data Concepts

The GPIB interface has two modes of operation: command mode and data mode. The interface is in the command mode when the Attention (ATN) control line is true. The command mode is used to send talk and listen addresses and various interface commands such as group execute trigger (GET).

The interface is in the data mode when the ATN line is false. The data mode is used to convey device-dependent messages across the bus. The device-dependent messages include all of the oscilloscope-specific commands, queries, and responses found in this manual, including oscilloscope status information.

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LAN and GPIB Interfaces

Communicating Over the GPIB Interface

Device addresses are sent by the computer in the command mode to specify who talks and who listens. Because GPIB can address multiple devices through the same interface card, the device address passed with the program message must include the correct interface select code and the correct oscilloscope address.

Device Address = (Interface Select Code * 100) + Oscilloscope Address

The Oscilloscope is at Address 707 for Programming Examples

The programming examples in this manual assume that the oscilloscope is at device address 707.

Interface Select Code

Each interface card has a unique interface select code. This code is used by the computer to direct commands and communications to the proper interface. The default is typically “7” for the GPIB interface cards.

Oscilloscope Address

Each oscilloscope on the GPIB must have a unique oscilloscope address between decimal 0 and 30. This oscilloscope address is used by the computer to direct commands and communications to the proper oscilloscope on an interface. The default is typically “7” for this oscilloscope. You can change the oscilloscope address in the Utilities, Remote Interface dialog box.

Do Not Use Address 21 for an Oscilloscope Address

Address 21 is usually reserved for the Computer interface Talk/Listen address, and should not be used as an oscilloscope address.

2-7

LAN and GPIB Interfaces

Communicating Over the LAN Interface

The device address used to send commands and receive data using the LAN interface is located in the GPIB Setup dialog box as shown below.

LAN Address

GPIB Setup Dialog Box

The following C example program shows how to communicate with the oscilloscope using the LAN interface and the Agilent Standard Instrument Control Library (SICL).

#include <sicl.h>

#define BUFFER_SIZE 1024

main() { INST Bus; int reason; unsigned long actualcnt; char buffer[ BUFFER_SIZE ];

/* Open the LAN interface */ Bus = iopen( “lan[130.29.71.203]:hpib7,7” ); if( Bus != 0 ) { /* Bus timeout set to 20 seconds */ itimeout( Bus, 20000 );

/* Clear the interface */ iclear( Bus ); /* Query and print the oscilloscope’s Id */ iwrite( Bus, “*IDN?”, 5, 1, &actualcnt ); iread( Bus, buffer, BUFFER_SIZE, &reason, &actualcnt );

2-8

buffer[ actualcnt - 1 ] = 0;

printf( “%s\n”, buffer ); iclose( Bus ); } }

LAN and GPIB Interfaces

Communicating Over the LAN Interface

2-9

Bus Commands

The following commands are IEEE 488.1 bus commands (ATN true). IEEE 488.2 defines many of the actions that are taken when these commands are received by the oscilloscope.

Device Clear

The device clear (DCL) and selected device clear (SDC) commands clear the input buffer and output queue, reset the parser, and clear any pending commands. If either of these commands is sent during a digitize operation, the digitize operation is aborted.

Group Execute Trigger

The group execute trigger (GET) command arms the trigger. This is the same action produced by sending the RUN command.

Interface Clear

The interface clear (IFC) command halts all bus activity. This includes unaddressing all listeners and the talker, disabling serial poll on all devices, and returning control to the system computer.

2-10

Message Communication and System Functions

This chapter describes the operation of oscilloscopes that operate in compliance with the IEEE 488.2 (syntax) standard. It is intended to give you enough basic information about the IEEE 488.2 standard to successfully program the oscilloscope. You can find additional detailed information about the IEEE 488.2 standard in ANSI/IEEE Std 488.21987, “IEEE Standard Codes, Formats, Protocols, and Common

Commands.”

This oscilloscope series is designed to be compatible with other Agilent Technologies IEEE 488.2 compatible instruments. Oscilloscopes that are compatible with IEEE 488.2 must also be compatible with IEEE 488.1 (GPIB bus standard); however, IEEE 488.1 compatible oscilloscopes may or may not conform to the IEEE 488.2 standard. The IEEE 488.2 standard defines the message exchange protocols by which the oscilloscope and the computer will communicate. It also defines some common capabilities that are found in all IEEE 488.2 oscilloscopes. This chapter also contains some information about the message communication and system functions not specifically defined by IEEE 488.2.

3-2

Message Communication and System Functions

Protocols

The message exchange protocols of IEEE 488.2 define the overall scheme used by the computer and the oscilloscope to communicate. This includes defining when it is appropriate for devices to talk or listen, and what happens when the protocol is not followed.

Functional Elements

Before proceeding with the description of the protocol, you should understand a few system components, as described here.

Input Buffer The input buffer of the oscilloscope is the

memory area where commands and queries are stored prior to being parsed and executed. It allows a computer to send a string of commands, which could take some time to execute, to the oscilloscope, then proceed to talk to another oscilloscope while the first oscilloscope is parsing and executing commands.

Output Queue The output queue of the oscilloscope is the

memory area where all output data or response messages are stored until read by the computer.

Parser The oscilloscope’s parser is the component

that interprets the commands sent to the oscilloscope and decides what actions should be taken. “Parsing” refers to the action taken by the parser to achieve this goal. Parsing and execution of commands begins when either the oscilloscope recognizes a program message terminator, or the input buffer becomes full. If you want to send a long sequence of commands to be executed, then talk to another oscilloscope while they are executing, you should send all of the commands before sending the program message terminator.

3-3

Message Communication and System Functions

Protocols

Protocol Overview

The oscilloscope and computer communicate using program messages and response messages. These messages serve as the containers into which sets of program commands or oscilloscope responses are placed.

A program message is sent by the computer to the oscilloscope, and a response message is sent from the oscilloscope to the computer in response to a query message. A query message is defined as being a program message that contains one or more queries. The oscilloscope will only talk when it has received a valid query message, and therefore has something to say. The computer should only attempt to read a response after sending a complete query message, but before sending another program message.

Remember this Rule of Oscilloscope Communication

The basic rule to remember is that the oscilloscope will only talk when prompted to, and it then expects to talk before being told to do something else.

Protocol Operation

When you turn the oscilloscope on, the input buffer and output queue are cleared, and the parser is reset to the root level of the command tree.

The oscilloscope and the computer communicate by exchanging complete program messages and response messages. This means that the computer should always terminate a program message before attempting to read a response. The oscilloscope will terminate response messages except during a hard copy output.

After you send a query message, the next message should be the response message. The computer should always read the complete response message associated with a query message before sending another program message to the same oscilloscope.

The oscilloscope allows the computer to send multiple queries in one query message. This is called sending a “compound query.” Multiple queries in a query message are separated by semicolons. The responses to each of the queries in a compound query will also be separated by semicolons.

Commands are executed in the order they are received.

Protocol Exceptions

If an error occurs during the information exchange, the exchange may not be completed in a normal manner.

3-4

Message Communication and System Functions

Protocols

Suffix Multiplier

The suffix multipliers that the oscilloscope will accept are shown in Table 3-1.

Table 3-1

Table 3-2

Value Mnemonic Value Mnemonic

1E18 EX 1E-3 M

1E15 PE 1E-6 U

1E12 T 1E-9 N

1E9 G 1E-12 P

1E6 MA 1E-15 F

1E3 K 1E-18 A

Suffix Unit

The suffix units that the oscilloscope will accept are shown in Table 3-2.

Suffix Referenced Unit

VVolt

S Second

3-5

3-6

Status Reporting

An overview of the oscilloscope’s status reporting structure is shown in Figure 4-1. The status reporting structure shows you how to monitor specific events in the oscilloscope. Monitoring these events lets you determine the status of an operation, the availability and reliability of the measured data, and more.

• To monitor an event, first clear the event, then enable the event. All of the events are cleared when you initialize the oscilloscope.

• To generate a service request (SRQ) interrupt to an external computer, enable at least one bit in the Status Byte Register.

The Status Byte Register, the Standard Event Status Register group, and the Output Queue are defined as the Standard Status Data Structure Model in IEEE 488.2-1987. IEEE 488.2 defines data structures, commands, and common bit definitions for status reporting. There are also oscilloscope-defined structures and bits.

4-2

Figure 4-1

Status Reporting Overview Block Diagram

The status reporting structure consists of the registers shown here.

Table 4-1 lists the bit definitions for each bit in the status reporting data structure.

Table 4-1 Status Reporting Bit Definition

Bit Description Definition

PON Power On Indicates power is turned on.

URQ User Request Not Used. Permanently set to zero.

CME Command Error Indicates if the parser detected an error.

EXE Execution Error Indicates if a parameter was out of range or was

DDE Device Dependent Error Indicates if the device was unable to complete an

QYE Query Error Indicates if the protocol for queries has been violated.

RQL Request Control Indicates if the device is requesting control.

inconsistent with the current settings.

operation for device-dependent reasons.

4-3

Bit Description Definition

OPC Operation Complete Indicates if the device has completed all pending

operations.

OPER Operation Status RegisterIndicates if any of the enabled conditions in the

RQS Request Service Indicates that the device is requesting service.

MSS Master Summary Status Indic ates if a device has a reason for requesting s ervice.

ESB Event Status Bit Indicates if any of t he enabled conditions in the St andard

MAV Message Available Indicates if there is a response in the output queue.

MSG Message Indicates if an advisory has been displayed.

USR User Ev ent Register Indic ates if any of the enabled conditions have occurred

TRG Trigger Indicates if a trigger has been received.

WAIT TRIG Wait for Trigger Indicates the oscilloscope is armed and ready for

Operation Status Register have occurred.

Event Status Register have occurred.

in the User Event Register.

trigger.

4-4

Status Reporting

Status Reporting Data Structures

The different status reporting data structures, descriptions, and interactions are shown in Figure 4-2. To make it possible for any of the Standard Event Status Register bits to generate a summary bit, you must enable the corresponding bits. These bits are enabled by using the *ESE common command to set the corresponding bit in the Standard Event Status Enable Register.

To generate a service request (SRQ) interrupt to the computer, you must enable at least one bit in the Status Byte Register. These bits are enabled by using the *SRE common command to set the corresponding bit in the Service Request Enable Register. These enabled bits can then set RQS and MSS (bit 6) in the Status Byte Register.

For more information about common commands, see the “Common Commands” chapter.

4-5

Figure 4-2

Status Reporting

Status Reporting Data Structures

4-6

Figure 4-2 (Continued)

Status Reporting

Status Reporting Data Structures

Status Reporting Data Structures (Continued)

4-7

Status Reporting

Status Byte Register

The Status Byte Register is the summary-level register in the status reporting structure. It contains summary bits that monitor activity in the other status registers and queues. The Status Byte Register is a live register. That is, its summary bits are set and cleared by the presence and absence of a summary bit from other event registers or queues.

If the Status Byte Register is to be used with the Service Request Enable Register to set bit 6 (RQS/MSS) and to generate an SRQ, at least one of the summary bits must be enabled, then set. Also, event bits in all other status registers must be specifically enabled to generate the summary bit that sets the associated summary bit in the Status Byte Register.

You can read the Status Byte Register using either the *STB? common command query or the GPIB serial poll command. Both commands return the decimalweighted sum of all set bits in the register. The difference between the two methods is that the serial poll command reads bit 6 as the Request Service (RQS) bit and clears the bit which clears the SRQ interrupt. The *STB? query reads bit 6 as the Master Summary Status (MSS) and does not clear the bit or have any effect on the SRQ interrupt. The value returned is the total bit weights of all of the bits that are set at the present time.

The use of bit 6 can be confusing. This bit was defined to cover all possible computer interfaces, including a computer that could not do a serial poll. The important point to remember is that if you are using an SRQ interrupt to an external computer, the serial poll command clears bit 6. Clearing bit 6 allows the oscilloscope to generate another SRQ interrupt when another enabled event occurs.

The only other bit in the Status Byte Register affected by the *STB? query is the Message Available bit (bit 4). If there are no other messages in the Output Queue, bit 4 (MAV) can be cleared as a result of reading the response to the *STB? query.

If bit 4 (weight = 16) and bit 5 (weight = 32) are set, a program would print the sum of the two weights. Since these bits were not enabled to generate an SRQ, bit 6 (weight = 64) is not set.

4-8

Status Reporting

Status Byte Register

Example 1 This HP BASIC example uses the *STB? query to read the contents of the

oscilloscope’s Status Byte Register when none of the register's summary bits are enabled to generate an SRQ interrupt.

10 OUTPUT 707;":SYSTEM:HEADER OFF;*STB?" !Turn headers off 20 ENTER 707;Result !Place result in a numeric variable 30 PRINT Result !Print the result 40 End

The next program prints 132 and clears bit 6 (RQS) of the Status Byte Register. The difference in the decimal value between this example and the previous one is the value of bit 6 (weight = 64). Bit 6 is set when the first enabled summary bit is set, and is cleared when the Status Byte Register is read by the serial poll command.

Example 2 This example uses the HP BASIC serial poll (SPOLL) command to read the

contents of the oscilloscope’s Status Byte Register.

10 Result = SPOLL(707) 20 PRINT Result 30 END

Use Serial Polling to Read the Status Byte Register

Serial polling is the preferred method to read the contents of the Status Byte Register because it resets bit 6 and allows the next enabled event that occurs to generate a new SRQ interrupt.

4-9

Status Reporting

Service Request Enable Register

Setting the Service Request Enable Register bits enables corresponding bits in the Status Byte Register. These enabled bits can then set RQS and MSS (bit 6) in the Status Byte Register.

Bits are set in the Service Request Enable Register using the *SRE command, and the bits that are set are read with the *SRE? query. Bit 6 always returns 0. Refer to the Status Reporting Data Structures shown in Figure 4-2.

Example This example sets bit 4 (MAV) and bit 5 (ESB) in the Service Request Enable

OUTPUT 707;"*SRE 48"

This example uses the parameter “48” to allow the oscilloscope to generate an SRQ interrupt under the following conditions:

• When one or more bytes in the Output Queue set bit 4 (MAV).

• When an enabled event in the Standard Event Status Register generates a summary bit that sets bit 5 (ESB).

Message Event Register

This register sets the MSG bit in the status byte register when an internally generated message is written to the advisory line on the oscilloscope. The message is read using the :SYSTEM:DSP? query. Note that messages written to the advisory line on the oscilloscope using the :SYSTEM:DSP command does not set the MSG status bit.

Trigger Event Register

This register sets the TRG bit in the status byte register when a trigger event occurs.

The trigger event register stays set until it is cleared by reading the register with the TER? query or by using the *CLS (clear status) command. If your application needs to detect multiple triggers, the trigger event register must be cleared after each one.

If you are using the Service Request to interrupt a computer operation when the trigger bit is set, you must clear the event register after each time it is set.

4-10

Status Reporting

Standard Event Status Register

The Standard Event Status Register (SESR) monitors the following oscilloscope status events:

• PON - Power On

• CME - Command Error

• EXE - Execution Error

• DDE - Device Dependent Error

• QYE - Query Error

• RQC - Request Control

• OPC - Operation Complete When one of these events occurs, the corresponding bit is set in the register.

If the corresponding bit is also enabled in the Standard Event Status Enable Register, a summary bit (ESB) in the Status Byte Register is set.

You can read the contents of the Standard Event Status Register and clear the register by sending the *ESR? query. The value returned is the total bit weights of all bits set at the present time.

Example This example uses the *ESR? query to read the contents of the Standard Event

Status Register.

10 OUTPUT 707;":SYSTEM:HEADER OFF" !Turn headers off 20 OUTPUT 707;"*ESR?" 30 ENTER 707;Result !Place result in a numeric variable 40 PRINT Result !Print the result 50 End

If bit 4 (weight = 16) and bit 5 (weight = 32) are set, the program prints the sum of the two weights.

4-11

Status Reporting

Standard Event Status Enable Register

For any of the Standard Event Status Register bits to generate a summary bit, you must first enable the bit. Use the *ESE (Event Status Enable) common command to set the corresponding bit in the Standard Event Status Enable Register. Set bits are read with the *ESE? query.

Example Suppose your application requires an interrupt whenever any type of error

occurs. The error status bits in the Standard Event Status Register are bits 2 through 5. The sum of the decimal weights of these bits is 60. Therefore, you can enable any of these bits to generate the summary bit by sending:

OUTPUT 707;"*ESE 60"

Whenever an error occurs, the oscilloscope sets one of these bits in the Standard Event Status Register. Because the bits are all enabled, a summary bit is generated to set bit 5 (ESB) in the Status Byte Register.

If bit 5 (ESB) in the Status Byte Register is enabled (via the *SRE command), a service request interrupt (SRQ) is sent to the external computer.

Disabled Standard Event Status Register Bits Respond, but Do Not Generate a Summary Bit

Standard Event Status Register bits that are not enabled still respond to their corresponding conditions (that is, they are set if the corresponding event occurs). However, because they are not enabled, they do not generate a summary bit in the Status Byte Register.

4-12

Status Reporting

Operation Status Register

This register hosts the following bits:

• Acquisition done bit (bit 0)

• WAIT TRIG bit (bit 5)

• Mask Test Summary bit (bit 9)

• Auto trigger bit (bit 11)

• Overload Summary bit (bit 12) The acquisition done bit is set by the Acquisition Done Event Register. The WAIT TRIG bit is set by the Trigger Armed Event Register and indicates

the trigger is armed. The Mask Test Summary bit is set whenever at least one of the Mask Test Event

Register bits is enabled. The auto trigger bit is set by the Auto Trigger Event Register. The Overload Summary bit is set whenever at least one of the Overload Event

set. The Operation Status Register is read and cleared with the OPER? query. The register output is enabled or disabled using the mask value supplied with the OPEE command.

4-13

Status Reporting

Operation Status Enable Register

For any of the Operation Status Register bits to generate a summary bit, you must first enable the bit. Use the OPEE (Operation Event Status Enable) command to set the corresponding bit in the Operation Status Enable Register. Set bits are read with the OPEE? query.

Example Suppose your application requires an interrupt whenever any event occurs in

the mask test register. The error status bit in the Operation Status Register is bit 9. Therefore, you can enable this bit to generate the summary bit by sending:

OUTPUT 707;”OPEE 512” ( hex 200 )

Whenever an error occurs, the oscilloscope sets this bit in the Mask Test Event Register. Because this bit is enabled, a summary bit is generated to set bit 9 (OPER) in the Operation Status Register.

If bit 7 (OPER) in the Status Byte Register is enabled (via the *SRE command), a service request interrupt (SRQ) is sent to the external computer.

Disabled Operation Status Register Bits Respond, but Do Not Generate a Summary Bit

Operation Status Register bits that are not enabled still respond to their corresponding conditions (that is, they are set if the corresponding event occurs). However, because they are not enabled, they do not generate a summary bit in the Status Byte Register.

4-14

Status Reporting

Mask Test Event Register

This register hosts the following bits:

• Mask Test Complete bit (bit 0)

• Mask Test Fail bit (bit 1)

• Mask Low Amplitude bit (bit 2)

• Mask High Amplitude bit (bit 3)

• Mask Align Complete bit (bit 4)

• Mask Align Fail bit (bit 5)

The Mask Test Complete bit is set whenever the mask test is complete. The Mask Test Fail bit is set whenever the mask test failed. The Mask Low Amplitude bit is set whenever the signal is below the mask

amplitude. The Mask High Amplitude bit is set whenever the signal is above the mask

amplitude. The Mask Align Complete bit is set whenever the mask align is complete. The Mask Align Fail bit is set whenever the mask align failed.

If any of these bits are set, the MASK bit (bit 9) of the Operation Status Register is set. The Mask Test Event Register is read and cleared with the MTER? query. The register output is enabled or disabled using the mask value supplied with the MTEE command.

4-15

Status Reporting

Mask Test Event Enable Register

For any of the Mask Test Event Register bits to generate a summary bit, you must first enable the bit. Use the MTEE (Mask Test Event Enable) command to set the corresponding bit in the Mask Test Event Enable Register. Set bits are read with the MTEE? query.

Example Suppose your application requires an interrupt whenever a Mask Test Fail

occurs in the mask test register. You can enable this bit to generate the summary bit by sending:

OUTPUT 707;”MTEE 2”

Whenever an error occurs, the oscilloscope sets the MASK bit in the Operation Status Register. Because the bits in the Operation Status Enable Register are all enabled, a summary bit is generated to set bit 7 (OPER) in the Status Byte Register.

If bit 7 (OPER) in the Status Byte Register is enabled (via the *SRE command), a service request interrupt (SRQ) is sent to the external computer.

Disabled Mask Test Event Register Bits Respond, but Do Not Generate a Summary Bit

Mask Test Event Register bits that are not enabled still respond to their corresponding conditions (that is, they are set if the corresponding event occurs). However, because they are not enabled, they do not generate a summary bit in the Operation Status Register.

4-16

Status Reporting

Trigger Armed Event Register

This register sets bit 5 (Wait Trig bit) in the Operation Status Register and bit 7 (OPER bit) in the Status Byte Register when the oscilloscope becomes armed.

The ARM event register stays set until it is cleared by reading the register with the AER? query or by using the *CLS command. If your application needs to detect multiple triggers, the ARM event register must be cleared after each one.

If you are using the Service Request to interrupt the computer operation when the trigger bit is set, you must clear the event register after each time it is set.

Acquisition Done Event Register

This register sets bit 0 (Acq Done bit) in the Operation Status Register and bit 7 (OPER bit) in the Status Byte Register when the oscilloscope acquisition is completed.

The DONE event register stays set until it is cleared by reading the register with the ADER? query or by using the *CLS command. If your application needs to detect multiple acquisitions, the DONE event register must be cleared after each acquisition.

If you are using the Service Request to interrupt the computer operation when the trigger bit is set, you must clear the event register after each time it is set.

4-17

Status Reporting

Error Queue

As errors are detected, they are placed in an error queue. This queue is a firstin, first-out queue. If the error queue overflows, the last error in the queue is replaced with error -350, “Queue overflow.” Any time the queue overflows, the oldest errors remain in the queue, and the most recent error is discarded. The length of the oscilloscope's error queue is 30 (29 positions for the error messages, and 1 position for the “Queue overflow” message).

The error queue is read with the :SYSTEM:ERROR? query. Executing this query reads and removes the oldest error from the head of the queue, which opens a position at the tail of the queue for a new error. When all the errors have been read from the queue, subsequent error queries return 0, “No error.”

The error queue is cleared when any of these events occur:

• When the oscilloscope is powered up.

• When the oscilloscope receives the *CLS common command.

• When the last item is read from the error queue.

For more information on reading the error queue, refer to the :SYSTEM:ERROR? query in the System Commands chapter. For a complete list of error messages, refer to the chapter, “Error Messages.”

Output Queue

The output queue stores the oscilloscope-to-computer responses that are generated by certain oscilloscope commands and queries. The output queue generates the Message Available summary bit when the output queue contains one or more bytes. This summary bit sets the MAV bit (bit 4) in the Status Byte Register. You may read the output queue with the HP Basic ENTER statement.

4-18

Status Reporting

Message Queue

The message queue contains the text of the last message written to the advisory line on the screen of the oscilloscope. The queue is read with the :SYSTEM:DSP? query. Note that messages sent with the :SYSTEM:DSP command do not set the MSG status bit in the Status Byte Register.

Clearing Registers and Queues

The *CLS common command clears all event registers and all queues except the output queue. If *CLS is sent immediately following a program message terminator, the output queue is also cleared.

4-19

Figure 4-3

Status Reporting Decision Chart

4-20

Status Reporting

Clearing Registers and Queues

4-21

Status Reporting

Clearing Registers and Queues

4-22

Programming Conventions

This chapter describes conventions used to program the Infiniium-Series Oscilloscopes, and conventions used throughout this manual. A description of the command tree and command tree traversal is also included.

5-2

Programming Conventions

Truncation Rule

The truncation rule is used to produce the short form (abbreviated spelling) for the mnemonics used in the programming headers and parameter arguments.

Command Truncation Rule

The mnemonic is the first fo ur characters of the keyword, unless the fourth character is a vowel. Then the mnemonic is the first three characters of the keyword. If the length of the keyword is four characters or less, this rule does not apply, and the short form is the same as the long form.

Table 5-1 shows how the truncation rule is applied to commands.

Table 5-1

Mnemonic Truncation

Long Form Short Form How the Rule is Applied

RANGE RANG Short form is the first four characters of the keyword.

PATTERN PATT Short form is the first four characters of the keyword.

DISK DISK Short form is the same as the long form.

DELAY DEL Fourth character is a vowel; short form is the first three

characters.

5-3

Programming Conventions

The Command Tree

The command tree in Figure 5-1 shows all of the commands in the InfiniiumSeries Oscilloscopes and the relationship of the commands to each other. The IEEE 488.2 common commands are not listed as part of the command tree because they do not affect the position of the parser within the tree.

When a program message terminator (<NL>, linefeed - ASCII decimal 10) or a leading colon (:) is sent to the oscilloscope, the parser is set to the “root” of the command tree.

Command Types

The commands in this oscilloscope can be viewed as three types: common commands, root level commands, and subsystem commands.

• Common commands are commands defined by IEEE 488.2 and control some functions that are common to all IEEE 488.2 instruments. These commands are independent of the tree and do not affect the position of the parser within the tree. *RST is an example of a common command.

• Root level commands control many of the basic functions of the oscilloscope. These commands reside at the root of the command tree. They can always be parsed if they occur at the beginning of a program message or are preceded by a colon. Unlike common commands, root level commands place the parser back at the root of the command tree. AUTOSCALE is an example of a root level command.

• Subsystem commands are grouped together under a common node of the command tree, such as the TIMEBASE commands. You may select only one subsystem at a given time. When you turn on the oscilloscope initially, the command parser is set to the root of the command tree and no subsystem is selected.

5-4

Programming Conventions

The Command Tree

Tree Traversal Rules

Command headers are created by traversing down the command tree. A legal command header from the command tree would be :TIMEBASE:RANGE. This is referred to as a compound header. A compound header is a header made up of two or more mnemonics separated by colons. The compound header contains no spaces. The following rules apply to traversing the tree.

Tree Traversal Rules

A leading colon or a program message terminator (<NL> or EOI true on the last byte) places the parser at the root of the command tree. A leading colon is a colon that is the first character of a program header. Executing a subsystem command places the oscilloscope in that subsystem until a leading colon or a program message terminator is found.

In the command tree, use the last mnemonic in the compound header as a reference point (for example, RANGE). Then find the last colon above that mnemonic (TIMEBASE:). That is the point where the parser resides. You can send any command below this point within the current program message without sending the mnemonics which appear above them (for example, REFERENCE).

5-5

Figure 5-1

Programming Conventions

The Command Tree

Command Tree

5-6

Figure 5-2

Programming Conventions

The Command Tree

Command Tree (Continued)

5-7

Figure 5-3

Programming Conventions

The Command Tree

Command Tree (Continued)

5-8

Figure 5-4

Programming Conventions

The Command Tree

Command Tree (Continued)

5-9

Figure 5-5

Programming Conventions

The Command Tree

Command Tree (Continued)

5-10

Figure 5-6

Programming Conventions

The Command Tree

Command Tree (Continued)

5-11

Figure 5-7

Programming Conventions

The Command Tree

BUS<N>, DIGital<N>, and POD<N> commands only available on the MSO oscilloscopes

Command Tree (Continued)

5-12

Tree Traversal Examples

The OUTPUT statements in the following examples are written using HP BASIC 5.0. The quoted string is placed on the bus, followed by a carriage return and linefeed (CRLF).

Example 1 Consider the following command:

OUTPUT 707;":CHANNEL1:RANGE 0.5;OFFSET 0"

The colon between CHANNEL1 and RANGE is necessary because :CHANNEL1:RANGE is a compound command. The semicolon between the RANGE command and the OFFSET command is required to separate the two commands or operations. The OFFSET command does not need :CHANNEL1 preceding it because the :CHANNEL1:RANGE command sets the parser to the CHANNEL1 node in the tree.

Example 2 Consider the following commands:

Programming Conventions

The Command Tree

OUTPUT 707;":TIMEBASE:REFERENCE CENTER;POSITION 0.00001"

OUTPUT 707;":TIMEBASE:REFERENCE CENTER" OUTPUT 707;":TIMEBASE:POSITION 0.00001"

In the first line of example 2, the “subsystem selector” is implied for the POSITION command in the compound command.

A second way to send these commands is shown in the second part of the example. Because the program message terminator places the parser back at the root of the command tree, you must reselect TIMEBASE to re-enter the TIMEBASE node before sending the POSITION command.

Example 3 Consider the following command:

OUTPUT 707;":TIMEBASE:REFERENCE CENTER;:CHANNEL1:OFFSET 0"

In this example, the leading colon before CHANNEL1 tells the parser to go back to the root of the command tree. The parser can then recognize the :CHANNEL1:OFFSET command and enter the correct node.

5-13

Programming Conventions

Infinity Representation

The representation for infinity for this oscilloscope is 9.99999E+37. This is also the value returned when a measurement cannot be made.

Sequential and Overlapped Commands

IEEE 488.2 makes a distinction between sequential and overlapped commands. Sequential commands finish their task before the execution of the next command starts. Overlapped commands run concurrently. Commands following an overlapped command may be started before the overlapped command is completed.

Response Generation

As defined by IEEE 488.2, query responses may be buffered for these reasons:

• When the query is parsed by the oscilloscope.

• When the computer addresses the oscilloscope to talk so that it may read the response.

This oscilloscope buffers responses to a query when the query is parsed.

EOI

The EOI bus control line follows the IEEE 488.2 standard without exception.

5-14

Sample Programs

Sample programs for the Infiniium-Series Oscilloscopes are shipped on a CD ROM with the instrument. Each program demonstrates specific sets of instructions.

This chapter shows you some of those functions, and describes the commands being executed. Both C and BASIC examples are included.

The header file is:

• gpibdecl.h

The C examples include:

•init.c

•gen_srq.c

• srqagi.c

•srqnat.c

• learnstr.c

• sicl_IO.c

•natl_IO.c

The BASIC examples include:

•init.bas

•srq.bas

•lrn_str.bas

The sample program listings are included at the end of this chapter.

6-2

Sample Program Structure

This chapter includes segments of both the C and BASIC sample programs. Each program includes the basic functions of initializing the interface and oscilloscope, capturing the data, and analyzing the data.

In general, both the C and BASIC sample programs typically contain the following fundamental segments:

Segment Description

main program Defines global variables and constants, specifies include files,

and calls various functions.

initialize Initializes the GPIB or LAN interface and oscilloscope, and sets

acquire_data Digitizes the waveform to capture data.

auto_measurements Performs simple parametric measurements.

transfer_data Brings waveform data and voltage/timing information (the

The BASIC programming language can be used to set up and transfer data to your PC. However, because of the limitations of BASIC, it is not the best language to use when transferring large amounts of data to your PC.

up the oscilloscope and the ACQuire subsystem.

preamble) into the computer.

6-3

Sample Programs

Sample C Programs

Segments of the sample programs “init.c” and “gen_srq.c” are shown and described in this chapter.

init.c - Initialization

/* init. c */

/* Command Order Example. This program demonstrates the order of commands suggested for operation of the 548xx oscilloscope via GPIB. This program initializes the oscilloscope, acquires data, performs automatic measurements, and transfers and stores the data on the PC as time/voltage pairs in a comma-separated file format useful for spreadsheet applications. It assumes a SICL INTERFACE exists as ’hpib7’ and an 548xx oscilloscope at address 7. It also requires a waveform connected to Channel 1.

See the README file on the demo disk for development and linking information. */

#include <stdio.h> /* location of: printf() */ #include <stdlib.h> /* location of: atof(), atoi() */ #include "gpibdecl.h" /* prototypes, global declarations, constants */

void initialize( void ); /* initialize the oscilloscope */ void acquire_data( void ); /* digitize waveform */ void auto_measurements( void ); /* perform built-in automatic measurements */ void transfer_data( void ); /* transfers waveform data from oscilloscope to PC */ int convert_data( int, int ); /* converts data to time/voltage values */ void store_csv( FILE *, int ); /* stores time/voltage pairs to */ /* comma-separated variable file format */

The include statements start the program. The file “gpibdecl.h” includes prototypes and declarations that are necessary for the Infiniium Oscilloscope sample programs.

This segment of the sample program defines the functions, in order, that are used to initialize the oscilloscope, digitize the data, perform measurements, transfer data from the oscilloscope to the PC, convert the digitized data to time and voltage pairs, and store the converted data in comma-separated variable file format.

See the following descriptions of the program segments.

6-4

Sample Programs

Sample C Programs

init.c - Global Definitions and Main Program

/* GLOBALS */ int count; double xorg,xinc; /* values necessary for conversion of data */ double yorg,yinc; int Acquired_length; char data[MAX_LENGTH]; /* data buffer */ double time_value[MAX_LENGTH]; /* time value of data */ double volts[MAX_LENGTH]; /* voltage value of data */

void main( void ) { /* initialize interface and device sessions */ /* note: routine found in sicl_IO.c or natl_IO.c */

if( init_IO( ) ) {

/* initialize the oscilloscope and interface and set up SRQ */ initialize( ); acquire_data( ); /* capture the data */

/* perform automated measurements on acquired data */ auto_measurements( );

/* transfer waveform data to the PC from oscilloscope */ transfer_data( ); close_IO( ); /* close interface and device sessions */ } } /* end main( ) */

The init_IO routine initializes the oscilloscope and interface so that the oscilloscope can capture data and perform measurements on the data. At the start of the program, global symbols are defined which will be used to store and convert the digitized data to time and voltage values.

6-5

Sample Programs

Sample C Programs

init.c - Initializing the Oscilloscope

/* * Function name: initialize * Parameters: none * Return value: none * Description: This routine initializes the oscilloscope for proper * acquisition of data. The instrument is reset to a known state and the * interface is cleared. System headers are turned off to allow faster * throughput and immediate access to the data values requested by queries. * The oscilloscope time base, channel, and trigger subsystems are then * configured. Finally, the acquisition subsystem is initialized. */ void initialize( void ) { write_IO("*RST"); /* reset oscilloscope - initialize to known state */ write_IO("*CLS"); /* clear status registers and output queue */

write_IO(":SYSTem:HEADer OFF"); /* turn off system headers */

/* initialize time base parameters to center reference, */ /* 2 ms full-scale (200 us/div), and 20 us delay */ write_IO(":TIMebase:REFerence CENTer;RANGe 2e-3;POSition 20e-6");

/* initialize Channel1 1.6V full-scale (200 mv/div); offset -400mv */ write_IO(":CHANnel1:RANGe 1.6;OFFSet -400e-3");

/* initialize trigger info: channel1 waveform on positive slope at 300mv */ write_IO(":TRIGger:EDGE:SOURce CHANnel1;SLOPe POSitive"); write_IO(":TRIGger:LEVel CHANnel1,-0.40");

/* initialize acquisition subsystem */ /* Real time acquisition - no averaging; memory depth 1,000,000 */ write_IO(":ACQuire:MODE RTIMe;AVERage OFF;POINts 1000000");

} /* end initialize() */

6-6

Sample Programs

Sample C Programs

init.c - Acquiring Data

/* * Function name: acquire_data * Parameters: none * Return value: none * Description: This routine acquires data according to the current * instrument settings. */ void acquire_data( void ) { /* * The root level :DIGitize command is recommended for acquisition of new * data. It will initialize data buffers, acquire new data, and ensure that * acquisition criteria are met before acquisition of data is stopped. The * captured data is then available for measurements, storage, or transfer * to a PC. Note that the display is automatically turned off by the * :DIGitize command and must be turned on to view the captured data. */

write_IO(":DIGitize CHANnel1"); write_IO(":CHANnel1:DISPlay ON"); /* turn on channel 1 display which is */ /* turned off by the :DIGitize command */

} /* end acquire_data() */

6-7

Sample Programs

Sample C Programs

init.c - Making Automatic Measurements

/* * Function name: auto_measurements * Parameters: none * Return value: none * Description: This routine performs automatic measurements of volts * peak-to-peak and frequency on the acquired data. It also demonstrates * two methods of error detection when using automatic measurements. */

void auto_measurements( void ) { float frequency, vpp; unsigned char vpp_str[16]; unsigned char freq_str[16]; int bytes_read;

/* * Error checking on automatic measurements can be done using one of two methods. * The first method requires that you turn on results in the Measurements * subsystem using the command :MEASure:SEND ON. When this is on, the oscilloscope * will return the measurement and a result indicator. The result flag is zero * if the measurement was successfully completed, otherwise a non-zero value is * returned which indicates why the measurement failed. * * The second method simply requires that you check the return value of the * measurement. Any measurement not made successfully will return with the value * +9.999E37. This could indicate that either the measurement was unable to be * performed, or that insufficient waveform data was available to make the * measurement. */ /* * METHOD ONE - turn on results to indicate whether the measurement completed * successfully. Note that this requires transmission of extra data from the * oscilloscope. */ write_IO(":MEASure:SENDvalid ON"); /* turn results on */

/* query volts peak-to-peak channel 1 */ write_IO(":MEASure:VPP? CHANnel1");

bytes_read = read_IO(vpp_str,16L); /* read in value and result flag */

if (vpp_str[bytes_read-2] != ’0’) printf("Automated vpp measurement error with result %c\n", vpp_str[bytes_read-2]); else printf("VPP is %f\n",(float)atof(vpp_str));

6-8

Agilent 54831B Programmer’s Reference

Specifications and Main Features

Frequently Asked Questions

User Manual

In This Book

Introduction to Programming

Communicating with the Oscilloscope

Output Command

Device Address

Instructions

Instruction Header

White Space (Separator)

Braces

Ellipsis

Square Brackets

Command and Query Sources

Program Data

Header Types

Duplicate Mnemonics

Query Headers

Program Header Options

Character Program Data

Numeric Program Data

Embedded Strings

Program Message Terminator

Common Commands within a Subsystem

Selecting Multiple Subsystems

Programming Getting Started

Initialization

Example Program using HP Basic

Using the DIGITIZE Command

Receiving Information from the Oscilloscope

String Variable Example

Numeric Variable Example

Definite-Length Block Response Data

Multiple Queries

Oscilloscope Status

LAN and GPIB Interfaces

LAN Interface Connector

GPIB Interface Connector

Default Startup Conditions

Interface Capabilities

GPIB Command and Data Concepts

Communicating Over the GPIB Interface

Communicating Over the LAN Interface

Bus Commands

Message Communication and System Functions

Protocols

Status Reporting

Status Reporting Data Structures

Status Byte Register

Service Request Enable Register

Message Event Register

Trigger Event Register

Standard Event Status Register

Standard Event Status Enable Register

Operation Status Register

Operation Status Enable Register

Mask Test Event Register

Mask Test Event Enable Register

Trigger Armed Event Register

Acquisition Done Event Register

Error Queue

Output Queue

Message Queue

Clearing Registers and Queues

Programming Conventions

Truncation Rule

The Command Tree

Infinity Representation

Sequential and Overlapped Commands

Response Generation

Sample Programs

Sample Program Structure

Sample C Programs