Anritsu 37247C Programmer Manual

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SERIES

37XXXC

VECTOR NETWORK ANALYZER

PROGRAMMING MANUAL

490 JARVIS DRIVE · MORGAN HILL, CA 95037-2809

P/N: 10410-00227

REVISION: D

PRINTED: MARCH 2004

WARRANTY

The ANRITSU product(s) listed on the title page is (are) warranted against defects in materials and workmanship for one year from the date of shipment. ANRITSU's obligation covers repairing or replacing products which prove to be defective during the warranty period. Buyers shall prepay transportation charges for equipment returned to ANRITSU for warranty repairs. Obligation is limited to the original purchaser. ANRITSU is not liable for con sequential damages.

LIMITATION OF WARRANTY

The foregoing warrantydoes not apply to ANRITSU connectors that have failed due to normal wear. Also,the warranty does not apply to defects resulting from improper or inadequate maintenance by the Buyer,unauthorized modification or misuse,oroperation outside of the environmental specifications of the product. No other warranty is expressed or implied, and the remedies provided herein are the Buyer's sole and exclusive remedies.

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V Connector and K Connector are registered trademarks of ANRITSU Company. Windows,Excel,QuickBASIC,C,andQuick C are registered trademarks of Microsoft Corporation.

NOTICE

ANRITSU Company has prepared this manual for use by ANRITSU Company personnel and cus tomers as a guide for the proper installation, operation and maintenance of ANRITSU Company equipment and computer programs.The drawings, specifications, and information contained herein are the property of ANRITSU Company,and any unauthorized use or disclosure of these drawings, specifications, and information is prohibited; they shall not be reproduced, copied, or used in whole or in part as the basis for manufacture or sale of the equipment or software programs without the prior written consent of ANRITSU Company.

UPDATES

Updates to this manual, if any, may be downloaded from the Anritsu Internet site at:

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Part 1 — GPIB Interface

Chapter 1 — Series 37XXXC GPIB Programmer Interface

This chapter provides an introduction to the 37XXXC GPIB programmer interface and GPIB commu nications.

Chapter 2 — GPIB Programming Basics

This chapter provides programming information, including equipment and controller setup and ele mental GPIB programming techniques.

Chapter 3 — Series 37XXXC Programming Examples

This chapter provides sample program elements that demonstrate common 37XXXC operations. These sample elements are useful as an aid in developing 37XXXC programs.

Part 2 — GPIB Function Groups

Chapter 4 — Measurement Functions

This chapter provides a detailed description of the 37XXXC specific GPIB commands that control the various data display and measurement control functions of the 37XXXC.

Chapter 5 — Calibration Functions

This chapter describes the 37XXXC error correction (calibration) functions and the commands used to implement a measurement calibration. It also describes the AutoCal function and provides a listing of applicable commands.

Chapter 6 — Markers and Limits Functions

This chapter describes commands used for data analysis, which consists of markers and limits function commands.

Chapter 7 — Remote-Only Functions

This chapter describes 37XXXC functions that support operations typically required when in the remote-only (GPIB) mode. The commands described consist of data transfer, error reporting, SRQ/status reporting, 488.2 common commands, and synchronization.

Chapter 8 — System Functions

This chapter describes the commands used to implement certain system functions. They consist of hard copy, system state, save/recall, disk function, and diagnostics commands.

Chapter 9 — Special Applications Functions

This chapter describes the commands used to implement special measurement functions. They con sist of time domain, multiple source, sweep control, rear panel output, CW sweep, gain compression, Millimeter Wave System commands.

37XXXC PM i

Part 3 — Programming Reference

Chapter 10 — Command Dictionary

This chapter provides an alphabetically-ordered, dictionary-type listing and description of all 37XXXC GPIB programming commands. The listing for each command includes relevant details about the command.

Chapter 11 — Instrument Data

This chapter provides general (non-command specific) tabular information for the 37XXXC. Much of this information is presented in Chapters 4 through 10, but is provided in this chapter for easy ac cess.

Chapter 12 — Error Messages

This chapter provides a list of all Error Messages including those related to remote-only (GPIB) op eration of the 37XXXC.

Part 4 — Supplemental Data

Appendix A — Introduction to the IEEE 488 Bus

This appendix contains an introduction to the IEEE 488 Bus (GPIB). This material is intended to as sist new users in understanding GPIB basics.

Appendix B — GPIB Quick Reference Guide

This appendix provides a quick reference to all 37XXXC GPIB commands. Each reference lists the command name, a brief description of the command function, and a reference to the pertinent Chapter in this manual.

ii 37XXXC PM

Part 1 The GPIB Interface

This part consists of three chapters that describe how the IEEE- 488 (GPIB) interface is implemented within the 37XXXC Vector Network Analyzer and how to perform basic GPIB communications operations.

Chapter 1 – briefly describes the 37XXXC GPIB programmer in-

terface and describes the communication to and from the interface during remote-only (GPIB) operation of the 37XXXC.

Chapter 2 – provides a tutorial for performing basic GPIB op

erations such as sending and receiving messages, synchronizing instrument operations, setting timeouts, and status checking.

Chapter 3 – provides sample program elements to familiarize

the user with 37XXXC programming techniques.They are also useful as an aid in developing 37XXXC programs.

Chapter 1 Series 37XXXC GPIB Programmer Interface

Table of Contents

1-1 MANUAL SCOPE ...................1-3

1-2 INTRODUCTION ...................1-3

1-3 RELATED MANUALS ................1-3

1-4 REMOTE OPERATION................1-3

GPIB Setup Menu ......................1-4

Interface Connection.....................1-5

Local Operation Key .....................1-5

Remote Operation LED Indicators .............1-7

1-5 GPIB COMMUNICATION ..............1-8

Bus Interface Function Messages..............1-8

37XXXC Specific Messages .................1-8

Separator

Characters ..........................1-9

Terminator

Character...........................1-9

GPIB Error

Conditions ..........................1-9

Testing the 37XXXC GPIB Operation ...........1-10

1-6 IEEE 488.2 SUMMARY ...............1-11

Chapter 1 Series 37XXXC GPIB Programmer Interface

1-1 MANUAL SCOPE This manual provides IEEE 488 bus (GPIB) programming information

and data for all models of the Series 37000C Vector Network Analyzer. It contains the entire command set for programming all features. Con sequently,not all of the codes documented in this manual apply to all models within the series (371XXC, 372XXC,373XXC). The reader needs to be aware of the feature set available within the model for which programming is being written. Feature set information is docu mented in the applicable operation manual (OM) for any particular model.

1-2 INTRODUCTION This chapter contains a brief introduction to the 37XXXC GPIB inter-

face and programming environment.

1-3 RELATED MANUALS The series contains an operation manual, a maintenance manual, and

a GPIB Quick Reference Guide (Appendix B). ANRITSU Part numbers and manual titles are given below:

Manual Title Part Number

37XXXC Operation Manual (OM) 10410-00226 37XXXC Maintenance Manual (MM) 10410-00228 37XXXC GPIB Quick Reference Guide 10410-00229

1-4 REMOTE OPERATION The following paragraphs describe the 37XXXC facilities for remote

operation. The 37XXXC fully supports the IEEE 488.2–1992 GPIB standard. All

37XXXC front panel functions (except Power on/off and GPIB Test) can be controlled remotely using the GPIB commands listed in this manual and an external computer equipped with an IEEE 488 GPIB controller. When in the GPIB operating mode,the 37XXX VNA func tions as both a listener and a talker.

37XXXC PM 1-3

REMOTE OPERATION GENERAL INFORMATION

GPIB Setup Menu The 37XXXC VNA GPIB address defaults to 6. This value may be

changed via the Utility Menu key's GPIB ADDRESSES menu (below).

System State

Default

Program

Utility

Figure 1-1. GPIB Address Menu

SELECT UTILITY

FUNCTION OPTIONS

GPIB ADDRESSES

DISPLAY INSTRU MENT STATE PARAM S

GENERAL DISK UTILITIES

CALIBRATIO N COMPONENT UTILITIES

COLOR CONF IGU RAT ION

DATA ON(OFF) DRAWING

BLANKING FREQUENCY INFORM ATIO N

PRESS <ENTER>

TO SELECT

OR TURN ON/OFF

GPIB ADDRESSES

IEEE 488.2 GPIB INTERFACE

ADDRESS 6

DEDICATED GPIB INTERFACE

EXTERNAL SOURCE 4

PLOTTER 8

POWER METER 13

FREQUENCY COUNTER 7

1-4 37XXXC PM

GENERAL INFORMATION REMOTE OPERATION

Interface Connection Connect your external controller to the IEEE 488.2 GPIB interface

connector on the rear panel (left). A pinout listing of this connector is contained in Figure 1-2.

PrinterOut

CRTDegaussCRTBrt

10MHzRef

Display

VGAOUT

ExternalI/O

BiasFuses

ReferenceExtension

Port1 Port2

RAIn RBIn RBOut

RAOut

Do not connect your external GPIB controller to the “Dedi cated GPIB Interface” connector (located below the “IEEE

488.2 GPIB interface” connector (left). This dedicated GPIB port is used by the 37XXXC to control external GPIB devices, such as a plotter,second frequency source, fre

NOTE

quency counter,or a power meter.

IEEE 488.2 Interface

Dedicated GPIB Interface

Displa

The GPIB system can accommodate up to 15 devices at any one time. To achieve maximum performance on the bus,proper timing and volt

age level relationships must be maintained. If either the cable length between separate instruments or the accumulated cable length be

tween all instruments is too long, the data and control lines cannot be driven properly and the system may fail to perform. The following guidelines should be observed:

No more than 15 instruments may be installed on the bus (in-

cluding the controller). Total accumulative cable length (in meters) may not exceed two

times the number of bus instruments or 20 meters—whichever is less.

Individual cable length should not exceed 4 meters.

2/3 of the devices must be powered on.

Devices should not be powered on while bus is in operation (that is; actively sending or receiving messages, data, etc.).

Minimize cable lengths to achieve maximum data transfer rates.

Local Operation Key Press the Ret Loc key (below) to quickly restore the 37XXXC to local

operation. Local operation will be restored unless the 37XXXC is pro grammed for local lockout; the Local Lockout LED indicator will be lit.

789

Enter

123

10-3Clear

Channel

Setup

Auto Scale

Trace

Memory

Clear

Ret Loc

Data

Points

Device

Domain

Hold

Video

Option Menu

IFBW

Avg/

Average

Smooth

Trac e

Smooth

Limits

Ch1 Ch2

Marker

Readout

Ch3 Ch4

Marker

Graph

Set

Type

Default

Utility

Program

Save/

Begin

Apply

Recall

Cal

Scale

Start

Stop

Ref

Plane

Params

37XXXC PM 1-5

REMOTE OPERATION GENERAL INFORMATION

12 11 10

9 8 7 6 5 4 3 2 1

24 23 22 21 20 19 18 17 16 15 14 13

Pinout Diagram

PIN NAME DESCRIPTION

1-4 DIO 1 thru DIO 4 Data Input/Output.Bitsare HIGH with the data is logical0andLOW when the data is

logical 1.

5 EOI End Or Identify. A low-true state indicates that the last byte of a multibyte message

has been placed on the line.

6DAVData Valid. A low-true state indicates that the talker has (1) sensed that NRFD is

LOW, (2) placed a byte of data on the bus, and (3) waited an appropriate length of time for the data to settle.

7 NRFD Not Ready For Data. A high-true state indicates that valid data has not yet been ac

cepted by a listener.

8 NDAC NotData Accepted. Alow-truestate indicates that the current databytehas been ac

cepted for internal processing by a listener.

9 IFC Interface Clear. A low-true state places all bus instruments in a known state—such

as, unaddressed to talk, unaddressed to listen, and service request idle.

10 SRQ Service Request. Alow-true state indicates that abusinstrumentneeds service from

the controller.

11 ATN Attention. A low-true state enables the controller to respond to both it's own lis

ten/talk address andtoappropriateinterfacemessages—such as, device clear and serial poll.

12 Shield Ground Point.

13-16 DIO 5 thru DIO 8 Data Input/Output. Bits are high with the data is logical 0 and LOW when the data is

logical 1.

17 REN Remote Enable. A low-true state enables bus instruments to be operated remotely,

when addressed.

18-

Figure 1-2. Pinout Diagram, IEEE 488.2 GPIB Connector

GND Logic ground.

1-6 37XXXC PM

GENERAL INFORMATION REMOTE OPERATION

789

Enter

123

10-3Clear

Channel

Setup

Data

Points

Device

Domain

Hold

Option

Video

Auto

Scale

IFBW

Avg/ Smooth

Trace

Average

Trac e

Memory

Smooth

Default

Utility

Begin

Apply

Program

Cal

GPIB Remote

Talk

Listen

SRQ

Local Lockout

Ch1 Ch2

Limits

Marker

Readout

Ch3 C h 4

Marker

Graph

Set

Type

Save/ Recall

Scale

Start

Stop

Ref

Plane

Params

Remote Operation

LED Indicators

GPIB Remote Indicators (above) signal operational status of the GPIB, as described below:

Remote:

Lights when the 37XXXC switches to remote (GPIB) control. It remains lit until the unit returns to local control.

Talk:

Lights when you address the 37XXXC to talk and remains lit until unaddressed to talk.

Listen:

Lights when you address the 37XXXC to listen and remains lit until unaddressed to talk.

SRQ:

Lights when the 37XXXC sends a Service Request (SRQ) to the exter nal controller. The LED remains lit until the 37XXXC receives a serial poll or until the controller resets the SRQ function.

Local Lockout:

Lights when a local lockout message is received. The LED remains lit until the message is rescinded. When lit, you cannot return the 37XXXC to local control via the front panel.

Audible Indicators A single beep is issued as follows:

(1) on a GPIB error, (2) when a user warning is issued (see Chapter 12, Operational Error

Messages)

(3) when a test limit line has been exceeded, if the limits testing beep

function has been set (see Chapter 6) (4) on system reset. (5) any time the user's attention is required, such as at the end of a

calibration step.

37XXXC PM 1-7

GPIB COMMUNICATION GENERAL INFORMATION

1-5 GPIB COMMUNICATION The following paragraphs present a short summary of 37XXXC GPIB

communication. Subjects covered are program messages, sepa rator/termination characters,status reporting, and GPIB error condi tions and corresponding 37XXXC responses. Refer to Chapter 7, Remote-Only Operation, for detailed description of these topics.

The primary GPIB messages that effect 37XXXC operation consist of two major groups; Bus Interface Function messages, and Instrument Specific messages.

Bus Interface

Function Messages

These are low level bus messages defined by IEEE 488.1. A discussion of these messages is beyond the scope of this programming manual. For further information, please refer to your GPIB controller documen tation and/or to IEEE 488.1 Standards documents.Also refer to Ap pendix A at the end of this Programming Manual for a brief primer on the GPIB Interface.Table 1-1 summarizes some of the key Interface Function Messages and the 37XXXC response to them.

Table 1-1. IEEE-488 Interface Function Messages

Interface Function

Message

DCL SDC

GTL Go To Local Yes Returns the 37XXXC to local (front panel) control. GET Group Execute Trig-

IFC Interface Clear No Stops the 37XXXC GPIB from talking/listening. LLO Local Lockout No Disables the front panel RETURN TO LOCAL key. REN Remote Enable No Places the 37XXXC in remote when addressed to listen.

Message Function

Device Clear Selected Device Clear

ger

Addressed

Command

Yes

Yes Executes a string of commands defined by the IEEE 488.2

Resets the 37XXXC GPIB communication functions. Resets the 37XXXC GPIB communication functions.

common command *DDT. A GET is also done by using the *TRG command (see Chapter 10, Command Dictionary).

37XXXC VNA Response

37XXXC Specific

Messages

The 37XXXC specific GPIB messages (also known as commands, que ries, and mnemonics) are used to control 37XXXC front panel func

tions. They also provide for remote only operations such as data transfers, status reporting and service request generation, error re porting, and instrument-to-application program timing synchroniza

tion. Refer to Chapter 10, Command Dictionary; Appendix B, Quick Refer

ence Guide; and Chapters 4-9 for information on all 37XXXC com

mands. The commands are organized both alphabetically and by command function groups.There are many examples throughout this manual to assist you in learning and using a desired command.

Most 37XXXC commands are three character contractions of their functional descriptions.Examples include: OM1 (Output Marker 1),

1-8 37XXXC PM

GENERAL INFORMATION GPIB COMMUNICATION

IFV (input Frequency List), TRS (Trigger Sweep), WFS (Wait for a Full Sweep), OFD (Output Final [display format] Data), and PFS (Print Full Screen).

Numeric parameter entry commands must be followed by a numeric value. These commands can optionally accept a units or suffix termi nator mnemonic. For example, SRT 2 GHZ (set start frequency to 2 GHz.)

Query commands,typically ending in a question mark (?), are used to inquire about the state of a particular instrument function. Many 37XXXC setup commands have corresponding query commands listed in the same section as the basic setup command. An example is the

MK1? query. It outputs the setting of Marker 1 Frequency, where the MK1 command sets Marker 1 frequency.

IEEE 488.2 Common commands, which always start with the asterisk character (*), are defined by the IEEE 488.2 Standard. They are used to implement many standard instrument GPIB operations such as querying when an operation completes, status reporting,self test, and querying the instrument identification string. These commands are described throughout the Programming Manual in the specific funtional group where they are used. A consolidated listing of these commands can be found in Table 1-2, item 12 below and in Chapter 7. An example IEEE 488.2 Common command is the *IDN? query (Output Instrument ID String.)

Separator

Characters

Terminator

Character

GPIB Error

Conditions

Separator characters are used to delimit program message elements sent to or received from the 37XXXC. The permitted characters: semicolon (;), comma (,), and space ( ) and their usage is shown below.

Character Used to separate

;

Space A command, its numerical entry value, and suffix mnemonic.

Multiple commands and multiple output response messages. Multiple ASCII data elements for a single command.

The only allowed terminator character for 37XXXC GPIB messages is the linefeed character (0A, decimal 10).

The 37XXXC responds to GPIB errors in the following manner:

A beep is issued.

An error message is displayed on the screen.

A bit is set in the Standard Event Status Register, and, if en

abled, an SRQ is generated.

37XXXC PM 1-9

GPIB COMMUNICATION GENERAL INFORMATION

An entry is written into the non-volatile Service Log describing

the error condition, along with time and date and, often, details helpful in handling the error.When full, error entries at the bot tom of the log are removed to make room for new entries.

If the error is GPIB related, the error message and the offending

program message, if applicable, can be output over the GPIB via a query command. The previous error, if any, is also available via another query.

The bits set in the Standard Event Status Register for GPIB errors are as follows:

Bit 5 - Command Error (CME)

Invalid syntax, unrecognized command or command arguments, sepa raters or terminators that do not conform to correct IEEEE 488.2 for mats. The 37XXXC will ignore the remainder of commands in that

program message.

Bit 4 - Execution Error (EXE)

This bit is set if: (1) A data entry parameter is out of range or not applicable. (2) Action is impossible. (3) Action is not possible in the current context or instrument state, or

if a required option is not fitted.

Testing the 37XXXC

GPIB Operation

Bit 3 - Device Dependent Error (DDE)

This bit is set if a valid requested action failed due to an instrument specific error condition, such as attempting to access a bad floppy disk.

Bit 2 - Query Error (QYE)

This bit is set if the 37XXXC cannot provide the requested data. For example, if an output is attempted when no data has been requested or available,or if the output buffer is cleared due to sending more com mands when data from a previous request has not yet been output.

Refer to Chapter 12, Error messages, for a listing of all 37XXXC error messages (including GPIB errors).

The following test can be used to check your GPIB cable and 37XXXC GPIB connectors.

1. Disconnect all GPIB cables from the 37XXXC.

2. Connect your GPIB cable between the two GPIB connectors on the

37XXXC rear panel.

3. Invoke the test from the front panel as follows: Option Menu key,

DIAGNOSTICS,PERIPHERAL TESTS,GPIB TEST. The test will run for a few seconds, then report the result on the front panel dis play.

1-10 37XXXC PM

GENERAL INFORMATION IEEE 488.2 SUMMARY

1-6 IEEE 488.2 SUMMARY Table 1-2 provides answers to the “Device Documentation Require

ments” listed in the IEEE Standard 488.2-1992. It is also a good sum mary of the GPIB operational characteristics of the 37XXXC.

Table 1-2. 37XXXC IEEE 488.2 Standard Documentation Summary (1 of 3)

Number Requirement Item Implementation in VNA

1 Interface Function Subsets Implemented SH1, AH1, T6, L4, SR1, RL1, PP1, DC1, DT1, C0, E2. 2 Device behavior when the user (unit) GPIB address

is set outside of the 0–30 range

3 When is a user address change recognized? New address is accepted and entry color remains

4 Description of settings at power-on The front panel setup that was in effect prior to power

VNA returns an Out-of-Range error,issues an audible beep, and the entry color on front panel menu display is changed to red. Entered address is not accepted.

green.

down will be restored, except: the 37XXXC will be taken out of hold if it was previously set. Periodic IF Cal will be returned to timed operation.

Memories saved:

1. GPIB address

2. Internal hardware calibration data

3. Information reported via the *IDN? and *OPT? queries.

4. Calibration coefficients

5. Normalized trace data

6. Stored front panel setups

Memories Cleared:

1. Service Request message.

2. Standard event status register (except the Power-On bit is set)

3. Extended event status register

4. Limit pass/fail status register

5. Enable registers for items 2 thru 4, above.

6. GPIB input and output queues.

7. Trigger action for *TRG and GET reset to null.

Data Transfer:

1. Data transfer is reset to MSB first for numerical array data transfers.

2. Data transfer format is reset to default, ASCII mode (FMA) for numerical array transfers.

3. Data pair format for OFD/IFD/OM1-OM6 commands is set to default (off) mode. (See command DPR0.)

Menu Displayed:

Setup Menu

37XXXC PM 1-11

IEEE 488.2 SUMMARY GENERAL INFORMATION

Table 1-2. 37XXXC IEEE 488.2 Standard Documentation Summary (2 of 3)

Number Requirement Item Implementation in VNA

5 Message exchange options

a. Size and behavior of input buffer a. Default size = 3 KByte. Size increases to required

amount, as needed, for <Arbitrary Block> transfers.

b. Queries that return more than one <RESPONSE MESSAGE UNIT>

c. Queries that generate a response when parsed c. All d. Queries that generate a response when read d. None e. Commands that are coupled e. None

6 Functional elements used in construction of device-

specific commands.

For the <Indefinite Length Arbitrary Block> data ele ments, the input buffer size for that element is 64 Kbyte. Attempting to program more data than 64 KByte will cause a loss of all data for that ele ment. A DDE error message will be issued to indi cate this condition. For <Definite Length Arbitrary Block> data elements, an attempt is made to set the buffer size for that element to the size indicated in the header. If there is insufficient system memory available at the time, all data for that element is lost. A DDE error message will be issued to indicate this condition.

b. None

See command descriptions.

7 Buffer size limitations 37XXXC Attempts to allocate amount required; sets

DDE error if not possible. (See 5a., above)

8 <PROGRAM DATA> elements that may appear

within an <expression>

9 Response syntax for queries See command descriptions.

10 Description of device-to-device message transfer

traffic that does not follow the rules for <RESPONSE

MESSAGES> 11 Size of block data responses Variable,See command descriptions for details. 12 IEEE.488.2 Common commands and queries that

are implemented

13 State of VNA following the successful completion of

the Calibration query 14 Maximum length of the block used to define the trig

ger macro (1.) The method of interpreting *TRG

within a *DDT command sequence (2.)

N/A (expressions are not used)

None

*CLS, *DDT, *DDT?, *ESE, *ESE?, *ESR?, *IDN?, *IST?, *OPC, *OPC?, *OPT?, *PRE, *PRE?, *RST, *SRE, *SRE?, *STB?, *TRG, *TST?, *WAI

Normal State

1. 255 characters.

2. On execution, the 37XXXC returns a command error and ignores the rest of the string.

1-12 37XXXC PM

GENERAL INFORMATION IEEE 488.2 SUMMARY

Table 1-2. 37XXXC IEEE 488.2 Standard Documentation Summary (3 of 3)

Number Requirement Item Implementation in VNA

15 Maximum length and complexity of macro labels;

maximum length of block used to define a macro; and how recursion is handled during macro expan

sion, if macro commands are implemented. 16 Response to common query *IDN?. ANRITSU, <Model>, <SN>, <SW revision> 17 Size of the protected user data storage area, if the

*PUD command or *PUD? query are implemented. 18 Size of resource description, if the *RDT command

or *RDT? query are implemented. 19 States affected by *RST, *LRN?, *RCL, and *SAV. *RST = default state (see Chapter 11),

20 Scope of the self test performed by *TST? command. Fully automated internal hardware testing/reporting.

21 Additional status data structures used in status re-

porting. 22 Statement describing whether each command is

overlapped or sequential. 23 Functional criteria that is met when an operation

complete message is generated in response to that

command.

N/A

*LRN, *RCL, *SAV not implemented

Failure results, if any, are written to the internal nonvolatile service log for user access.

Limits Event Status and Extended Event Status registers; refer to Chapter 7 for details.

All commands are sequential.

N/A – No overlapped commands.

24 Descriptions used for infinity and not-a-number. N/A

37XXXC PM 1-13/1-14

Chapter 2 GPIB Programming Basics

Table of Contents

2-1 INTRODUCTION ...................2-3

2-2 EQUIPMENT AND CONFIGURATION.......2-3

Required Equipment ...............2-3

Configuration ...................2-4

2-3 GPIB PROGRAM ELEMENTS............2-5

National Instruments GPIB Interface .....2-5

Definitions ....................2-5

2-4 INITIALIZING THE GPIB ..............2-6

2-5 SHUTTING DOWN THE GPIB SYSTEM ......2-6

2-6 DETECTING GPIB ERRORS.............2-7

Full Error Detection ...............2-7

Limited Handling Error Detection........2-7

NI488 Global Variables..............2-7

Example .....................2-7

2-7 OPERATION TIME OUT...............2-8

Example......................2-8

2-8 SENDING COMMANDS ...............2-9

Example: .....................2-9

37XXXC Commands Used ............2-9

2-9 RECEIVING DATA .................2-10

Example:.....................2-10

Error Handling: .................2-10

37XXXC Commands Used ...........2-11

2-10 SRQ HANDLING ..................2-11

Calculating the Binary Weighted Bit Value . . 2-11

Enabling Service Request............2-11

Example .....................2-11

Commands Used ................2-12

NI488

RQ Functions ..................2-12

2-11 COMPLETE OPERATIONS ............2-13

Example 1 ....................2-13

Example 2 ....................2-13

37XXXC Commands Used ...........2-14

Chapter 2 GPIB Programming Basics

2-1 INTRODUCTION This chapter contains a brief introduction to GPIB programming tech

niques and describes procedures to be used when preparing GPIB pro grams for the 37XXXC VNA. It includes information about equipment requirements and configuration for GPIB control of the 37XXXC VNA, and many programming tips.

Familiarity with manual (front panel) operation of the 37XXXC is as sumed. (Throughout this section, the 37XXXC VNA is referred to sim ply as “37XXXC”.) A complete description of front panel operation is contained in the appropriate 371XXC, 372XXC, or 373XXC Vector Network Analyzer System Operation Manual.

2-2 EQUIPMENT AND

CONFIGURATION

Required Equipment The following equipment represents a minimum GPIB controllable

The programming examples contained in this chapter assume the equipment listed below is present and configured as described.

37XXXC VNA system:

A 37XXXC Vector Network Analyzer.

A computer/controller that supports the IEEE 488 GPIB stan dard. The examples in this chapter address the IBM compatible computers.

An IEEE-488 GPIB interface (built in, or add-in peripheral card) with appropriate driver software. The National Instruments GPIB IEEE-488.2 interface is assumed for all examples in this chapter.

Appropriate software (any of the following):

Microsoft QuickBASIC, version 4.0 (or later)

Microsoft “C”, version 5.1 or later, or Quick C, version 2.5.

Any other programming language, or application software, that supports the IEEE 488 GPIB interface (Pascal, Fortran, etc.).

A GPIB cable (preferably 2 meters long).

37XXXC PM 2-3

EQUIPMENT AND CONFIGURATION GPIB PROGRAMMING BASICS

To: IEEE 488.2 Interface

From: IEEE 488 Interface card connector

Figure 2-1. Model 37XXXC Shown Connected to an IEEE 488.2 Controller

NOTE

The IBM PC and National Instruments GPIB interface were chosen for demonstrating the 37XXXC GPIB operation in this manual. Any other GPIB controller that conforms to the IEEE 488 standard can be used to interface to the 37XXXC.

connector

Prin te rOut

CRTDegaussCRTBrt

Configuration Configure the 37XXXC as shown in Figure 2-1. Apply power to the

37XXXC and allow the system software to load from disk. Once the

10MHzRef

Dis pla y

VGAOUT

Exte rnalI/O

ReferenceExte nsio n

BiasFuses

Port1 Port2

RAIn RBIn RBOut

RAOut

Connect here

Do not connect here

Displa

software has finished loading and start-up testing is complete, the 37XXXC is ready to be remotely controlled via the GPIB. It is impor

tant to note that the 37XXXC will not respond to GPIB commands un

til the 37XXXC system software has been loaded.

Connect a GPIB cable from the computer/controller to the rear panel IEEE 488.2 GPIB connector (left).

Apply power to the computer/controller and load the appropriate pro gramming language software (QuickBASIC, “C”, etc.).

The default GPIB address for the 37XXXC (6) is assumed for all exam

ples in this chapter.

2-4 37XXXC PM

GPIB PROGRAMMING BASICS GPIB PROGRAM ELEMENTS

2-3 GPIB PROGRAM

ELEMENTS

Instruments GPIB

National

Interface

The discussions in this chapter demonstrate basic GPIB programming concepts that are typical elements of most GPIB application programs.

The controller used to demonstrate these concepts is the National In struments 488.2 GPIB Interface which will be referred to as NI488 throughout this chapter.

NOTE

Regardless of the controller used, consult its documenta tion and software distribution disks for complete details and examples on setup and use of the controller's hard ware and interface software functions.

Throughout this chapter references will be made to variables, con stants, and controller function calls declared in the NI488 file that your application uses to interface to the GPIB controller. This file is decl.h for C and qbdecl.bas for QuickBASIC,and it must be in cluded in your GPIB program. Consult your documentation for the files used for other environments.

Including and compiling the appropriate NI488 file when preparing your application is what allows use of the NI488 GPIB interface procedures and function calls in your program. Also, the file named gpib.com must be installed in memory upon bootup of your computer. Typically, access to this file is through your system configuration file (that is,config.sys for DOS based computers).

The gpib.com is what allows your GPIB program to physically interface to the installed GPIB controller and to execute GPIB function calls during operation.

NOTE

Consult your controller's documentation for complete de tails on software and hardware setup, test, and use prior to proceeding with the following discussion. Knowledge of your controller and its operation will be assumed from this point forward.

Definitions The following definitions apply for the remainder of this chapter:

board = 0, Active controller board number

address = 6, GPIB address of the instrument.

Address List = addresList, list of GPIB addresses terminated with the NI488 constant NOADDR. For our examples the list con sists of two elements (6, NOADDR).

37XXXC PM 2-5

INITIALIZING THE GPIB GPIB PROGRAMMING BASICS

2-4 INITIALIZING THE GPIB Initializing is the process of directing your controller to take control of

the bus (become CIC — Controller In Charge) and setting the GPIB software to initial default settings.

NOTE

Default initial installation configuration is assumed for the NI488 hardware and software.

2-5 SHUTTING DOWN THE

GPIB SYSTEM

NI488 does this by sending an interface clear to the desired board us ing:

SendIFC(board)

The board will become CACS (Active controller). NI488 software al lows use of up to 4 controllers. The board specified by the SendIFC() function must be designated CIC – Controller In Charge in its setup and configuration. See NI488 config utility in NI488 documentation.

SendIFC() is also useful anytime you want to insure that your GPIB controller has control over the bus, the GPIB software is in its default parameters, and GPIB of all instruments on the bus is cleared and in idle state.

The following NI488 functions are also useful when initializing your application.

To place all instruments in remote state,use:

EnableRemote(board, addressList)

To clear GPIB operation of all instruments use:

DevClearList(board, addressList)

An important step in quitting a GPIB application is to shut down the GPIB interface. For the NI488 this is done by

Insuring that you have control over the bus.

Clearing all instruments' GPIB and placing them in an idle state.

Releasing the controller GPIB software and hardware.

Implement the above by sending:

SendIFC(board) ibonl(board, 0)

2-6 37XXXC PM

GPIB PROGRAMMING BASICS DETECTING GPIB ERRORS

2-6 DETECTING GPIB

ERRORS

Full Error Detection Full error detection and handling is an invaluable debugging tool that

Limited Handling

Error Detection

NI488 Global

Variables

It is important to use error checking code throughout your application program. Error checking usually does not significantly impact the speed of a GPIB application. This is because the GPIB bus operations are I/O operations whose execution time depends on a handshake pro cess. This process is typically much slower than executing (error checking) code in your computer's memory.

should be used to its fullest during development of your application. Error detection with at least a limited amount of handling should be

used after each GPIB I/O operation in your final program. This will in sure predictable operation of your application, proper system control, and accurate data processing.

The NI488 interface maintains three global variables useful in deter mining correct GPIB operations. These variables are updated after, and reflect the condition of, the last GPIB call to the interface. The variables are:

IBSTA

This variable provides the latest bus activity status; that is,errors, completions, time outs, etc.

q IBERR

This variable provides information on the type of error, if an error was reported in IBSTA.

IBCNT/IBCNTL

The number of data bytes transferred on the bus in the last operation. IBCNTL is the “long integer” version of IBCNT.

Example Error checking for the NI488 interface is as follows. After each GPIB

call, the IBSTA is checked for errors using the NI488 declared con stant EERR - in BASIC, or ERR in C. If true, the gpiberr() function is called to decode and display the global variables IBSTA, IBERR, and IBCNT. For example,for QuickBASIC,the following code is inserted af ter a GPIB call:

IF IBSTA% AND EERR THEN

CALL gpiberr (error during GPIB operation)

END IF

NOTE

The NI488 disks and documentation contain the source listing of the gpiberr() function. This function should be copied into your code and used after each GPIB function call. Use the example programs provided on the NI488 dis tribution disks.Note that gpiberr() can also be modified to fit a particular application's requirements.

37XXXC PM 2-7

OPERATION TIME OUT GPIB PROGRAMMING BASICS

2-7 OPERATION TIME OUT Setting GPIB time out is necessary to allow for lengthy instrument op

erations to complete before the application program continues with its processing. (Refer to paragraph 2-1, Waiting for Instrument Opera tions to Complete.)

Example The NI488 time out is set using the ibtmo() interface call, as follows:

ibtmo(instrument_handle, timeout_setting)

Where:

instrument_handle = The value returned by the ibfind() or

ibdev() interface call for the instrument. timeout_setting = A value that disables or sets the time out

setting. NI488 uses declared constants to represent the allowable time out settings,for example, the T100s constant is 100 seconds, T30ms is 30 milliseconds, TNone is 0, etc. The complete list is in the NI488 include file for your language (qbdecl.bas, decl.h).

NOTE

Consult NI488 documentation and distribution disks for information and an example on using ibtmo(), ifbind(), and ibdev().

2-8 37XXXC PM

GPIB PROGRAMMING BASICS SENDING COMMANDS

2-8 SENDING COMMANDS GPIB controllers provide for sending GPIB commands to an instru

ment (or the controller itself if its address is used). The NI488 uses several commands,the most common is:

Send (board, address, buffer, numBytes, eot_mode)

Where:

board, address = see section 2-3 for definitions.

buffer = String of one or more instrument specific GPIB com

mands from the defined list in the instrument's GPIB documenta tion.

buffer = String of one or more instrument specific GPIB com

mands from the defined list in the instrument's GPIB documenta tion.

numBytes = The number of bytes contained in the buffer.

eot_mode = The method used to signal end of transmission. This

is typically done using ASCII linefeed character 0A hex (10 decimal) and then setting EOI state (end of transmission) on the bus. The NI488 defines the following constants for use to setup end of transmission methods:

n NLend - Linefeed with EOI

DABend - EOI only

NULLend -Do nothing to mark end of transmission

Example: Send the 37XXXC at address 6, the commands “CH2;DSP;MAG”, from

37XXXC Commands

Used

controller number 0, using the linefeed with EOI to mark the end of transmission:

Send (0, 6, “CH2;DSP;MAG”,11,NLend)

The above example uses the following commands defined in the 37XXXC command set:

CH2 - sets active channel to 2,

DSP - displays only the active channel on the

whole screen,

MAG - displays the active channel's data in log magnitude format (dB).

NOTE

The semicolon (;) is used to separate the different com

mands.

37XXXC PM 2-9

RECEIVING DATA GPIB PROGRAMMING BASICS

2-9 RECEIVING DATA In order to receive data from an instrument over the GPIB, you must

first instruct the instrument to output the desired data. You do this by using one of the instrument's defined data output commands and the controller Send() function (see paragraph 2-8, “Sending commands”).

The instrument must then be given permission to start sending data (talk). The NI488 call to do this is:

Receive(board, address, buffer, numBytes,

eod_mode)

Where:

board, address = see section 2-3 for definitions.

buffer = The name of the memory address of the buffer where

the received data is to be placed. Typically this is an array of type characters (a string). Although, for binary data transfers, the NI488 software will accept an array of almost any type; that is. integer, floating point, etc.

numBytes = The maximum number of bytes to read from the in-

strument. Insure that “buffer” above is of at least this size. eod_mode = The method used to signal the controller to stop re-

ceiving data. Typically the NI488 constant STOPend is used (EOI state – end of transmission – set with the last byte). If you want to stop receiving when a certain transmission terminator character is received, then use the hex value of that character instead of the STOPend.

Example: Use the NI488 controller number 0, to send the 37XXXC at address 6,

the command “ONP” using the line feed with EOI to mark end of transmission:

Send(0, 6, “ONP”, 3, NLend)

Upon receiving a data output command, the 37XXXC will prepare the data requested and wait for the controller to put it in the talk state so it can put the data out on the bus. This is done by:

numBytes = 20

Receive(0, 6, buffer, numBytes, STOPend)

Error Handling: The number of bytes actually sent on the bus can now be retrieved

from the NI488 interface software by immediately storing the value of the IBCNT global variable in a program variable as follows:

actualReceivedBytes = IBCNT

2-10 37XXXC PM

GPIB PROGRAMMING BASICS SRQ HANDLING

37XXXC Commands

Used

If we expected an exact number of bytes to be received, we can com pare the requested number of bytes “numBytes” with the actual re ceived “actualReceievedBytes” and take some corrective action if they do not match. You should do this before continuing to the data process ing section of the program:

If numBytes ISNOTEQUALTO actualReceivedBytes then

Call gpiberr(”incorrect number of bytes received”)

END IF

NOTE

Consult your programming language syntax for the opera tor used to check in-equality, to use in place of ISNOTE QUALTO.

The above example uses the following commands defined in the 37XXXC command set:

ONP – Outputs the number of data points in the current sweep. It

will output the number represented in ASCII format.

2-10 SRQ HANDLING Controllers use a dedicated line on the GPIB to detect if an instrument

has requested service.An instrument sets this line when a predetermined set of conditions inside it have been met. These conditions are selected and programmed into the instrument by setting the Service Request Enable Register to a decimal value that corresponds to the bit values which, when true, will generate an SRQ. This is a binary weighted decimal value in the range 0 – 255.

Value

The decimal value of a bit in a register is equal to the number 2 raised to a power equal to the bit number. For example, the decimal value of bit 4 in the Service Request Enable Register is 2 raised to the power 4 which is: 2

To enable service request in the 37XXXC,use the command *SRE Service Request Enable,with the desired value.

when it has data to send, then output the number of points in the cur rent sweep. We need to enable bit 4 (MAV), Message Available, in the Service Request Enable Register,so a service request will be gener ated when the data is ready. The decimal value of bit 4 is 16 (2

The NI488 Send() function is used to send the 37XXXC at address 6, the commands “*SRE 16;ONP” (12 ASCII bytes), from controller num ber 0, using the linefeed with EOI to mark end of transmission:

= 16. Similarly, the decimal value of bit 0 is: 20=1.

Send(0, 6, “*SRE 16;ONP”, 12, NLend)”

= 16).

Calculating the Bi

nary Weighted Bit

Enabling Service

Request

Example Command the 37XXXC to request service; that is,generate an SRQ,

37XXXC PM 2-11

SRQ HANDLING GPIB PROGRAMMING BASICS

Commands Used The above example uses the following commands defined in the

37XXXC command set:

*SRE – Sends a Status Request Enable mask.

ONP – Outputs the number of sweep points.

NI488

RQ Functions

The following NI488 functions are useful in handling SRQ operations. Consult your NI488 documentation for full details.

To test for occurrence of SRQ:

TestSRQ(board, SRQset)

Where:

SRQset contains 1 if SRQ is set, or 0 if it is not.

To wait for occurrence of SRQ and report if it was set:

WaitSRQ(board, SRQset)

Where:

· SRQset contains 1 if SRQ was set within the time out allowed, or 0 if it was not. (See paragraph 2-8, Setting GPIB Operation Time Out.)

q To find out which instrument is requesting service (set SRQ), in-

struct the controller to perform a serial poll and return the results as follows:

FindRQS(board, addressList, statusByte)

Where:

statusByte = The status byte of the first requester found is returned in this variable.

The index in addressList that contains the address of the instrument requesting service is returned in the IBCNT global variable.

To read out the SRQ byte from an instrument:

ReadStatusByte(board, address, statusByte)

To parallel poll, see the following functions in the NI488 docu

mentation.

PPoll()

PPollConfig()

PPollUnconfig()

2-12 37XXXC PM

GPIB PROGRAMMING BASICS COMPLETE OPERATIONS

2-11 COMPLETE

OPERATIONS

Instruments often require a period of time to complete certain opera tions such as disk I/O, measurement sweep, data preparation, etc.. Your application program must allow the instrument time to complete these operations and be able to detect when operations are completed.

The simplest mechanism for synchronizing operations over the GPIB involve using the *OPC? -Operation Complete query and the *OPC Operation Complete command.

Example 1 Command the 37XXXC to perform a sweep and hold then place an

ASCII “1" in its output buffer (*OPC?) when done. The NI488 Send() function is used to send the 37XXXC at address 6,

the commands,”HLD;TRS;WFS;*OPC?”, from controller number 0, using the linefeed with EOI to mark end of transmission. The Re ceive() function is then used to hold the program from continuing processing until it receives the output of the *OPC command (or times out):

buffer = “HLD;TRS;WFS;*OPC?”

Send(0, 6, buffer, 17, NLend)

oneByte = 1

Receive(0, 6, buffer, oneByte, STOPend)

NOTE

The time out must be set high enough to allow the sweep to complete (see “Setting time outs” in paragraph 2-8).

Example 2 Now we will modify the above example to request service when bit 4

(MAV) in the Status Byte Register is set (*SRE 16) to let the program know when the *OPC? data is ready to be output. This overcomes the time out problem but it does increase program complexity.

buffer = “*SRE 16;HLD;TRS;WFS;*OPC?”

Send(0, 6, buffer, 25, NLend)

SRQset = 0

WHILE (SRQset = 0)

WaitSRQ(board, SRQset)

ReadStatusByte(board, address, statusByte)

oneByte = 1

Receive(0, 6, buffer, oneByte, STOPend)

NOTE

TestSRQ() can be used instead of WaitSRQ() to check for the occurrence of SRQ in the WHILE loop. This would allow your program to perform other tasks while waiting for SRQ inside the WHILE loop.

37XXXC PM 2-13

COMPLETE OPERATIONS GPIB PROGRAMMING BASICS

37XXXC Commands

Used

Examples 1 and 2 above used the following commands defined in the 37XXXC command set:

*SRE - sends a Status Request Enable value. HLD - places VNA into hold mode

TRS - triggers a sweep. Since the VNA is already

in hold mode, the hold mode is changed to single sweep and hold.

WFS - waits one full sweep and stops

*OPC? - outputs an ASCII “1” when operation is

complete

NOTE

Refer to Chapter 7, Remote Only Operations for more in formation and examples on status reporting and service request generation.

2-14 37XXXC PM

Chapter 3 Series 37XXXC Programming Examples

Table of Contents

3-1 INTRODUCTION ...................3-3

3-2 37XXXC PROGRAMMING EXAMPLES.......3-3

3-3 EXAMPLE 1 ......................3-4

3-4 EXAMPLE 2 ......................3-6

3-5 EXAMPLE 3 ......................3-8

3-6 EXAMPLE 4 .....................3-10

3-7 EXAMPLE 5 .....................3-11

3-8 EXAMPLE PROCEDURE 1 .............3-12

3-9 EXAMPLE FUNCTION 1 ..............3-13

3-10 EXAMPLE PROCEDURE 2 .............3-14

Chapter 3 Series 37XXXC Programming Examples

3-1 INTRODUCTION This chapter contains example programs to familiarize the user with

37XXXC programming.Familiarity with manual (front panel) opera tion of the 37XXXC is assumed. Throughout this section, the 37XXXC VNA is referred to simply as “37XXXC.”A complete description of front panel operation is contained in the 37XXXC Vector Network Analyzer System Operation Manual.

3-2 37XXXC PROGRAMMING

EXAMPLES

Also, it is assumed that you have read Chapters 1 and 2 and are famil iar with the information they contain. This information describes the various syntax and functions used in the example sequences presented throughout the chapter. This includes: Send, Receive,IBCNT, IBERR, ISNOTEQUALTO,and others.

The main sequences for five example 37XXXC programs are listed and explained in the following pages. In these examples, the NI488 function calls are abbreviated; refer to Chapter 2 and the NI488 documentation for full details. Refer to the 37XXXC Command Function groups and the Command listings in this manual for complete details on 37XXXC command operations.

NOTE

The functions and procedures called from the example se quences in paragraphs 3-3 through 3-7 are provided at the end of this chapter in paragraphs 3-8 through 3-10.

The intent of these example program sequences is to provide algo rithms useful when programming various features of the 37XXXC. You are encouraged to study these algorithms, copy them into your pro gramming environment, and tailor them for your language and appli cation.

37XXXC PM 3-3

EXAMPLE 1 PROGRAMMING EXAMPLES

3-3 EXAMPLE 1 This example sequence lists and explains some common 37XXXC op

erations.

Setup display and sweep frequencies

Send (0,6,“CH2;DSP;MPH;SRT 40 MHZ;STP 20 GHZ”,NLend)

Setup markers

Send (0,6,“MK1 40 MHZ;MK2 20 GHZ”,NLend)

Read and store current instrument setup

Request instrument setup string

Send (0,6,“OFP”,NLend)

Read instrument setup string

Receive(instrSetup, MAXSIZE, STOPend)

Get number of bytes transferred3

sizeInstrSetup = IBCNT

NOTE

Program variables instrSetup and sizeInstrSetup will be used later with the IFP command to input the saved setup string.

Read sweep frequencies

Trigger and wait for full sweep then hold

Send (0,6,“HLD;TRS;WFS”,NLend)

Wait for operations to complete (See “Wait for Instr()” example, page 3-12.)

WaitForInstr()

Request sweep frequencies (OFV): Use floating point (64 bit) binary format (FMB), Least Signifi cant Byte first ordering (LSB for IBM/compatible PCs only).

Send (0,6,“LSB;FMB;OFV”,NLend)

Get number of bytes to read: See Chapter 7, “Data Transfer” section for details on <Arbi trary Block> data transfers and structure of the header used to precede and give number of bytes in data block. (See “Get NumBytes( )” example, page 3-13.)

numBytes = GetNumBytes(address, headerString)

Read frequencies freqArray is a floating point double precision array of up to 1601 elements.

Receive(freqArray, numBytes, STOPend)

3-4 37XXXC PM

PROGRAMMING EXAMPLES EXAMPLE 1

Check for complete transfer

if (numBytes ISNOTEQUALTO IBCNT then

gpiberr(“Could not read freq list correctly”)

Reset instrument

Send reset command

Send (0,6,“*RST”,NLend)

Wait for operations to complete (page 3-12)

WaitForInstr()

Download and restore a previously saved setup

Command instrument to receive a setup string. Use “NUL

Lend” (see Chapter 2, paragraph 2-9.)

Send (0,6,“IFP ”,NLend)

NOTE

The space after the IFP command is needed to separate it from the setup string, which follows.

Send the setup string. Use “NLend” (see Chapter 2, paragraph

2-9.)

Send (0,6,(instrSetup, sizeInstrSetup),NLend)

Check if all data was sent correctly

if (sizeInstrSetup ISNOTEQUALTO IBCNT then

gpiberr(“Error sending setup string”)

Select instrument Marker 1 active

Send (0,6,“MR1”,NLend)

Read measurement trace

Trigger and wait for full sweep then hold

Send (0,6,“TRS;WFS;HLD”,NLend)

Wait for operations to complete (page 3-12)

WaitForInstr()

Request trace data: in final trace graph type values (OFD), in floating point (32 bit) binary format (FMC). Use Least significant Byte first or dering (LSB, for IBM/compatible PCs only)

Send (0,6,“LSB;FMC;OFD”,NLend)

37XXXC PM 3-5

EXAMPLE 2 PROGRAMMING EXAMPLES

Get number of bytes to read (page 3-13)

numBytes = GetNumBytes

Read out the trace data values.

Receive(traceData, numBytes, STOPend)

Check if all data was transferred

if (numBytes ISNOTEQUALTO IBCNT then

gpiberr(“Could not receive data.”)

Calculate number of sweep points in data string

POINTSIZE is 8 bytes for data transfers using the FMB for mat and 4 bytes if using the FMC format. See Chapter 7, “Data Transfer Commands.”

numFreqs = numBytes / POINTSIZE

Put instrument(s) in local to allow use of front panel

EnableLocal(board, addressList)

3-4 EXAMPLE 2 This example sequence lists and explains 37XXXC commands used for

automated 12 Term Calibration.

Display instructions to operator on computer screen

PRINT “Install 33KFKF Phase Equal Insertable on

PRINT “Install 3670K502 Thru Line female side to

PRINT “so the new Port 2 is the male end of the

PRINT “Shape the end of the thru so it is near

PRINT “(Press a key when ready)”

Set up calibration parameters

Send (0,6,“SCM;LTC;C12;ISN”,NLend)

Set up calibration frequencies

Send (0,6,“DFC;FRS 1 GHZ;FRI 100 MHZ;FRP 41;FIL;DFD”,NLend)

Set up connectors and loads

Send (0,6,“P1C;CFK;P2C;CMK;BBL”,NLend)

Begin calibration data collection

Send (0,6,“BEG”,NLend)

Wait for operations to complete (page 3-12)

WaitForInstr()

Port 1”

Port 2”

thru”

Port 1”

3-6 37XXXC PM

PROGRAMMING EXAMPLES EXAMPLE 2

Instruct operator via the controller screen...

To connect ISOLATION DEVICES between Ports 1 and 2 and wait for him; then measure devices. (See TakeCalData(),pg 3-14).

PRINT “Connect ISOLATION DEVICES between

PRINT “Press ENTER when ready” TakeCalData()

Instruct operator via the controller screen....

To connect BROADBAND LOADS between Ports 1 and 2 and wait for him; then measure devices.

PRINT “Connect BROADBAND LOADS between

PRINT “Press a key when ready” TakeCalData()

Instruct operator via the controller screen....

To connect OPEN to Port 1 and SHORT to Port 2 and wait for him; then measure devices.

PRINT “Connect OPEN to Port 1 and SHORT

PRINT “Press a key when ready” TakeCalData()

Ports 1 and 2”

Ports 1 and 2.”

to Port 2”

Instruct operator via the controller screen....

To connect SHORT to Port 1 and OPEN to Port 2 and wait for him; then measure devices.

PRINT “Connect SHORT to Port 1 and OPEN

PRINT “Press a key when ready” TakeCalData()

Instruct operator via the controller screen....

to Port 2

To connect Port 1 and Port 2 with the reminder to NOT INSTALL ADDITIONAL THRU LINES/ADAPTERS BETWEEN PORTS, and wait for him; then measure devices.

PRINT “Connect Port 1 and Port 2 but

PRINT “Press a key when ready” TakeCalData()

DO NOT INSTALL ADDITIONAL THRU LINES/ADAPTERS BETWEEN PORTS

37XXXC PM 3-7

EXAMPLE 3 PROGRAMMING EXAMPLES

3-5 EXAMPLE 3 This example sequence lists and explains 37XXXC commands for

transferring calibration error terms/coefficients.

Setup a Frequency Response Transmission Calibration.

Set up calibration parameters

Send (0,6,“SCM;LTC;CFT”,NLend)

Set up calibration frequencies

Send (0,6,“DFC;FRS 1 GHZ;FRI 100 MHZ;FRP 41;FIL;DFD”,NLend)

Begin calibration data collection

Send (0,6,“BEG”,NLend)

Wait for operations to complete (page 3-12)

WaitForInstr()

Instruct operator via the controller screen...

To connect THRU LINE between Ports 1 and 2 and wait for him.

PRINT “Connect THRU LINE between

PRINT “Press ENTER when ready”

Ports 1 and 2"

Measure thruline (page 3-12).

TakeCalData()

Read Calibration Coefficient Data from instrument and store the 488.2 data transfer header which is useful for sending the same size data array back to the 37XXXC later. Also calculate and store the number of frequency points read in.

Request the error term/coefficient array (OC1) in 64 bit Float ing Point format (FMB), Least Significant Byte order (LSB, for PCs only). See Chapter 7, “Data Transfer Commands” for the error terms returned by the OCx series commands.

Send (0,6,“LSB;FMB;OC1”,NLend)

Get number of bytes contained in the data string and store the header read from the 37XXXC into calHeader (string of charac ters). See GetNumBytes(), page 3-13.

numBytes = GetNumBytes(address, calHeader)

Read calibration data values calData is an 82 element double precision floating point array.

Receive(calData, numBytes, STOPend)

3-8 37XXXC PM

PROGRAMMING EXAMPLES EXAMPLE 3

Check if all data was transferred

if (numBytes ISNOTEQUALTO IBCNT) then

gpiberr(“Could not receive data.”)

Store number of calibration data bytes transferred

calDataSize = IBCNT

Calculate number of frequency points in the data trace if de

sired. POINTSIZE is 8 bytes for data transfer using the FMB format. See Chapter 7, “Data Transfer Commands.” The divi sion by two is because each data point represents a complex data pair (real, imaginary).

numFreqs = (CalDataSize / 2) / POINTSIZE

Send Calibration Coefficient Data to instrument

Simulate a Transmission Calibration

Command the 37XXXC to apply transmission calibration coef ficients to data (AFT), then input the calibration coefficient ar ray for transmission error term (IC1), in 64 bit Floating Point format (FMB), Least Significant Byte order (LSB, for use with PCs only). Use “NULLend” (see Chapter 2, paragraph 2-9.)

Send (0,6,“AFT;LSB;FMB;IC1”,NLend)

NOTE

Note the space after the IC1 command; it is needed to separate it from the calibration coefficient data array, which follows.

Send cal coefficient #1 data transfer header (same one that was received from the OC1 transfer). Use “NULLend” (see Chapter 2, paragraph 2-9.)

calHeaderSize = LENGTHOFSTRING(calHeader) Send (0,6, (calHeader, calHeaderSize, NULLend),NLend)

NOTE

Consult your compiler documentation for a function that returns length of a string.

Check for proper transfer

if (CalHeaderSize ISNOTEQUALTO IBCNT) then

gpiberr(“Data not sent properly”

Send cal coefficient #1 data. Use “NLend” (see Chapter 2, para

)

graph 2-9.)

Send (0,6,(calData, calDataSize),NLend)

37XXXC PM 3-9

EXAMPLE 4 PROGRAMMING EXAMPLES

Check for proper transfer

if (calDataSize ISNOTEQUALTO IBCNTl then

gpiberr(“Data not sent properly”)

Wait for operation to complete (page 3-12)

WaitForInstr()

Turn on/apply error correction

Send “CON”

3-6 EXAMPLE 4 This is an example sequence showing data string input to the

37XXXC.The string sent below is used to set hardcopy data output la bels.

The 37XXXC requires the double quote characters (“ ”) to delimit AS CII strings being sent to it. That is, to send a string called mystring you would actually send

“

mystring”.This presents a problem since

programming languages also delimit a character string with double quotes. In order to send the 37XXXC a quote(“)asaregular character, you must precede it with the backslash (\) character in the C language and with a quote character (”) in BASIC.

NOTE

A 37XXXC ASCII string may also be delimited using a single quote character(')atthebeginning and end of the string.In which case,the backslash (\) for C and the double quote (“) in BASIC are not required.

Define DUT Model in the data label. The following command sequence needs to be sent to the 37XXXC:

LMS “4_8_FILTER”

If using C use this syntax

Send (0,6,“LMS \”4_8_FILTER\”“,NLend)

If using BASIC use this syntax

Send (0,6,“LMS ““4_8_FILTER”””,NLend)

Here the same command sequence can be sent with the single quotes (' ') without the need for additional character as above.

Send (0,6,“LMS '4_8_FILTER'”,NLend)

If shutting down the GPIB immediately after this series of com

mands, then you must also make the controller wait for the 37XXXC to completely receive this data before shut down.

WaitForInstr()

3-10 37XXXC PM

PROGRAMMING EXAMPLES EXAMPLE 5

3-7 EXAMPLE 5 This example sequence lists and explains 37XXXC commands for

37XXXC internal disk operations.

Sweep, and store channel 1 trace data to memory

Send (0,6,“CH1;S11;CH3;S21;WFS;CH1;STD”,NLend)

Store trace memory data to hard disk

The following command sequence needs to be sent to the 37XXXC:

Send (0,6,“SAVE 'C:\CH1_S21.NRM'”,NLend)

Wait for operations to complete (page 3-12)

WaitForInstr()

Output channels 1 Tabular Data to instrument floppy disk

Send (0,6,“SAVE 'A:\CH1_S21.DAT'”,NLend)