Scpi Command Completion, Wai, Opc? | Agilent Technologies E4356A

SCPI Command Completion

SCPI commands sent to the power supply are processed either sequentially or in parallel. Sequential commands finish execution before a subsequent command begins. A parallel command can begin execution while a preexisting command is still executing (overlapping commands). Commands that affect trigger actions are among the parallel commands.

The *WAI, *OPC, and *OPC? common commands provide different ways of indicating when all transmitted commands, including any parallel ones, have completed their operations. The syntax and parameters for these commands are described in Chapter 7 - "Language Dictionary". Some practical considerations for using these commands are as follows:

*WAI	This prevents the power supply from processing subsequent commands until all pending operations
	are completed. If something prevents completion of an existing operation, *WAI can place the power
	supply and the controller in a "hang- up" condition.
*OPC?	This places a 1 in the Output Queue when all pending operations have completed. Because it
	requires your program to read the returned value from the queue before executing the next program
	statement, *OPC? could prevent subsequent commands from being executed.
*OPC	This sets the OPC status bit when all pending operations have completed. Since your program can
	read this status bit on an interrupt basis, *OPC allows subsequent commands to be executed.

The trigger subsystem must be in the Idle state in order for the status OPC bit to be true. Therefore, as far as triggers are concerned, OPC is false whenever the trigger subsystem is in the Initiated state. However, OPC is also false if there are any commands still pending.

Note	For a detailed discussion of WAI, OPC and *OPC?, see "Device/Controller Synchronization Techniques"
	in ANSI/IEEE Std 488.2.

Programming Examples

The examples given here are generic, without regard to the programming language or type of GPIB interface. Because SCPI commands are sent as ASCII output strings within the programming language statements, the SCPI syntax is independent of both programming language and interface.

Note	The examples are followed by sample program code written for three popular types of BASIC-controlled
	GPIB interfaces.

Important	The power supply responds simultaneously to both digital and analog progamming inputs. If it is
	receiving an input over the GPIB and a corresponding input from the front panel (and/or from the analog
	programming port), the power supply output will be the algebraic sum of the inputs.

52 Remote Programming

Image 52

Agilent Technologies E4356A manual Scpi Command Completion, Programming Examples, Wai, Opc?

Contents

Operating Programming Guide Certification Safety Summary General Safety Symbol Definitions Symbol DescriptionAcoustic Noise Information Herstellerbescheinigung Declaration Printing History Table of Contents General Information Operating Configurations Setting Up Remote Sense OperationController Connections Types of Scpi Commands Scpi Command Completion Programming ExamplesScpi Confirmed Commands NON-SCPI Commands Description Of Common Commands Description Of Subsystem Commands Calibration Commands Current SubsystemSystem Commands Command Summary Programming Parameters 105 109 111113 119Page Safety Considerations General InformationIntroduction Getting Started Map Operator Replaceable Parts List AccessoriesOptions Description Front Panel ProgrammingRemote Programming Analog Programming Output Ranges Output CharacteristicDownprogramming Installation InspectionDamage Packaging Material Items Supplied Location and Temperature Input Power Source Connecting Power Cord VXI plug&play Power Products Instrument Drivers Downloading and Installing the DriverAccessing Online Help Supported Applications System Requirements Power-On Checkout Turn-On CheckoutPreliminary Checkout Turn-On Checkout Using the Keypad Output CheckoutShifted Keys Backspace Key Checking the Current Function Press Prot Clear Checking The Save And Recall Functions Determining The Gpib AddressCase Of Trouble Line Fuse Selftest Errors Error MessagesPower-On Error Messages Checksum Errors Runtime Error MessagesError Display Power-On Selftest Errors Failed Test Runtime Errors Meaning Display Load Wire Selection Analog ConnectorUser Connections Rear Panel Connections Digital Connector Connecting the Power supply to the LoadOutput Isolation Capacitive Loads Battery Charging Inductive Loads Setting Up Remote Sense Operation Operating Configurations Connecting One Power supply to a Single LoadOVP Considerations Stability Connecting One Power supply To Multiple Loads Connecting Units in Auto-Parallel Connecting Units in Series Auto-Parallel Connection Remote Sensing Optional External Voltage Control Series Connection Remote Sensing Optional Stand-Alone Connections Controller ConnectionsLinked Connections 10. Controller Connections Getting Acquainted Front Panel OperationFront Panel Operation Control or Indicator Volts AmpsOCP SRQ Front Panel Controls and Indicators  System Keys Function Keys  Entry Keys Programming The Output Establishing Initial ConditionsProgramming Voltage Programming Overvoltage Protection Programming Current Unregulated Operation CV Mode vs. CC ModeProgramming Overcurrent Protection Setting The Gpib Address Types of Power supply Gpib AddressesSaving and Recalling Operating States Turn-On Conditions Changing the Power supply Gpib Address Action Display Shows Remote Programming Prerequisites for Remote ProgrammingExternal Documents Scpi References Gpib Capabilities of the Power supply Types of Scpi CommandsIntroduction To Scpi Conventions Active Header Path Traversing the Command TreeEffect of Optional Headers Including Common Commands Moving Among SubsystemsScpi Queries Value Coupling Types of Scpi Messages Structure of a Scpi MessageAbor VOLT? Volt Volt MAX Voltage, Volt, volt Outpprotdel Scpi Data Formats Numerical DataBoolean Data Character Data Scpi Command Completion Programming ExamplesWAI OPC? Programming Voltage and Current Programming Protection CircuitsChanging Outputs by Trigger Saving and Recalling States Writing to the Display Programming StatusDetecting Events via SRO Reading Specific Registers Setting the Gpib Address System ConsiderationsProgramming the Digital I/O Port Digdata Assigning the Gpib Address In Programs Assign @PS to Error Handling DOS DriversTypes of Drivers Agilent Basic Controllers Programming Some Power supply Functions Iout = OUTPUTS2 CODES$ = Output OFF*SAV CODES$ = STATOPEREVEN? Gosub While C O Scpi Confirmed Commands1 NON-SCPI Commands Language Dictionary Description Of Common Commands Command SyntaxCLS Meaning and Type ESE ESR?ESE ESR? PSC *STB? Parameters None Related Commands IDN?OPC OPC? *WAI OPC? OPT?OPC *TRIG WAI OPT? ESE *SRE RCLPSC *RST *SAV RST SAVPSC SAV SAV Bit Position Condition Bit Weight Bit Configuration of Status Byte RegisterSRE STB? TST? TRGWAI Description Of Subsystem Commands Calibration CommandsAbor Abor Curr Currtrig Current SubsystemCurrprotstat Digital Subsystem Display SubsystemDigdata Disp Dispmode Disptext Initiate Subsystem Measure SubsystemInit Initcont MEASCURR? MEASVOLT? Outp Output SubsystemOutpprotcle Outpprotdel Status Subsystem OutprelOutprelpol Statpres Status Operation Registers STATOPER?STATOPERCOND? Statoperenab Statoperntr Statoperptr Status Questionable RegistersSTATOUES? STATQUES? STATQUESCOND? StatquesenabStatquesntr Statquesptr Statusquestionableptr System Commands SYSTERR?Systlang SYSTVERS? Trigger Subsystem Voltage SubsystemTrig Trigsour Voltprot Voltagelevel 200 MAVoltagelevelimmediateamplitude Voltageleveltriggered Command Summary Command SummaryCommand Parameters Subsystem Commands Command Parameters Common Commands Command ParametersPower supply Programming Parameters see note Programming Parameters Power supply Status Structure Register CommandsStatus Reporting Operation Status Group Bit Signal Bit Configurations of Status Registers Meaning Status Byte and Service Request Enable RegistersOperation Status Group Standard Event Status Group CAL WTG UNR Status Questionable Commands Register Query Cleared By Questionable Status GroupStandard Event Status Group STATQUESNTR? Inhibit/Fault Indicator Status Byte Register Initial Conditions At Power On PON Power-On BitDetermining the Cause of a Service Interrupt Status Register Programming Examples Servicing an Operation Status Mode Event Monitoring Both Phases of a Status TransitionAdding More Operation Events Servicing Questionable Status Events Specifications Value Temperature Coefficients Typical Common Mode Noise CurrentMaximum Input VA and Power AC Input Ranges Output Terminal Isolation Table A-2. Supplemental Characteristics Parameter Value Command Processing TimeOutput Voltage Rise Time/Fall Time Full-load Programming Speed Up Time/Down Time Table A-2. Supplemental Characteristics General Procedure Test SetupCalibration Equipment Required Disabling the Calibration Mode Changing the Calibration PasswordFront Panel Calibration Entering the Calibration Values Table B-2. Typical Front Panel Calibration Procedure Action Display Response Table B-3. Gpib Calibration Error Messages Meaning Error MeaningFront Panel Command Corresponding Scpi Calibration Over The Gpib Calibration Language Dictionary CalcurrCalcurrlev Calpass Calstat CalvoltCalvoltlev Calvoltprot Basic Calibration Program Pause Clear Screen Figure B-2. Basic Calibration Program Verification Test Equipment RequiredList of Equipment Current Monitoring Resistor Performing The Tests Current Programming and Readback Accuracy Remove the short from across the loadVoltage Programming and Readback Current Programming and ReadbackPage Error Messages Power supply Hardware Error MessagesCalibration Error Messages System Error Messages Error Number Line Voltage Conversion Line Voltage ConversionPage Fault/Inhibit Operation Digital Port Functions Figure F-2. Example of Inhibit Input Changing The Port Configuration Figure F-4. Digital Port Configuration Jumper Digital I/O Operation Relay Link OperationIN/OUT 2 pin Common pin Figure F-6. Relay Link Connections Page Parallel Polling Compatibility LanguageCompatibility Language Table G-1. Arps Commands Description Arps Command1Similar Scpi Command RST Hold OFF Hold on Outpprotcle Volttrig Currtrig HOLD? TRGVOLTTRIG? CURRTRIG? Init Ontrig Init ON*TRG STO RCL STS? ASTS? TEST? ID? Systlang UNMASK? FAULT?TST? IDN? Systlang Index Index Index Scpi Curr Prot Stat CURR, Curr TRIG, 73 DIG Data Index Agilent Sales and Support Offices Manual Updates