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NI-488.2 User Manual for MacOS

1. GPIB NI 488 2 User Manual for MacOS July 1997 Edition Part Number 320897B 01 Copyright 1995 1997 National Instruments Corporation All rights reserved Internet Support support natinst com E mail info natinst com FTP Site ftp natinst com Web Address http www natinst com Bulletin Board Support BBS United States 512 794 5422 BBS United Kingdom 01635 551422 BBS France 01 48 65 15 59 Jm Fax on Demand Support 512 418 1111 O gt gt COOK lt C gt Telephone Support U S Tel 512 795 8248 Fax 512 794 5678 Os International Offices Australia 03 9879 5166 Austria 0662 45 79 90 0 Belgium 02 757 00 20 Canada Ontario 905 785 0085 Canada Qu bec 514 694 8521 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Germany 089 741 31 30 Hong Kong 2645 3186 Israel 03 5734815 Italy 02 413091 Japan 03 5472 2970 Korea 02 596 7456 Mexico 5 520 2635 Netherlands 0348 433466 Norway 32 84 84 00 Singapore 2265886 Spain 91 640 0085 Sweden 08 730 49 70 Switzerland 056 200 51 51 Taiwan 02 377 1200 United Kingdom 01635 523545 National Instruments Corporate Headquarters 6504 Bridge Point Parkway Austin TX 78730 5039 Tel 512 794 0100 Important Information Warranty Copyright Trademarks The media on which you receive National Instruments software are warranted not to fail to execute programming instructions due to defects in m
2. B 2 National Instruments Corporation Solutions ENOL 2 Appendix B Error Codes and Solutions e Any of the NI 488 2 routines that issue GPIB command bytes such as SendCmds PPoll Send Receive Following are some possible solutions e Use ibsicor SendIFC to make the GPIB board become CIC on the GPIB e Use ibrsc 1 to make sure your GPIB board is configured as System Controller e In multiple CIC situations always be certain that the CIC bit appears in the status word ibsta before attempting these calls If it does not appear you can perform an ibwait for CIC call to delay further processing until control is passed to the board Solutions ENOL usually occurs when a write operation is attempted with no Listeners addressed For a device write this error indicates that the GPIB address configured for that device in the software does not match the GPIB address of any device connected to the bus that the GPIB cable is not connected to the device or that the device is not powered on ENOL can occur in situations in which the GPIB board is not the CIC and the Controller asserts ATN before the write call in progress has ended Following are some possible solutions e Make sure that the GPIB address of your device matches the GPIB address of the device to which you want to write data e Use the appropriate hex code in ibcmd to address your device e Check your cable connections and make sure at least two thirds
3. National Instruments Corporation Chapter 6 GPIB Configuration Utility Default Configuration Your NI 488 2 software is shipped with the following default configurations The Auto Configure checkbox is selected All buses are configured as shown in the bus device frame in Figure 6 1 All devices are configured similarly to dev1 shown in the bus device frame in Figure 6 2 The devices dev1 through dev30 use bus gpib0 and are at the primary addresses through 30 respectively The devices dev31 through dev60 use bus gpib1 and are at the primary addresses 1 through 30 respectively The devices dev61 through dev64 use bus gpib2 and are at the primary addresses through 4 respectively m NI 488 Config Natinal Instruments GPIB Configuration Utility 0 1 2345 x Auto Configure scan bus WOOOOO 9 gpib gt 0 Interface Type PCI slots Bus Device Primary Address es Use Bus gpib0 g Repeat Addressing PCI Buffer 512k C Read END on EOS C Write END on EOS x Write END on Last Byte O seit eos Configuration Sets EOS Byte Lg Ss Figure 6 2 Device Default Settings in NI 488 Config National Instruments Corporation 6 3 NI 488 2 User Manual for MacOS Chapter 6 GPIB Configuration Utility Control Items NI 488 Config has the following four types of control items The rectangular boxes with drop shadows and labels to the left have pop up men
4. and TNT4882C are trademarks of National Instruments Corporation Product and company names listed are trademarks or trade names of their respective companies WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS National Instruments products are not designed with components and testing intended to ensure a level of reliability suitable for use in treatment and diagnosis of humans Applications of National Instruments products involving medical or clinical treatment can create a potential for accidental injury caused by product failure or by errors on the part of the user or application designer Any use or application of National Instruments products for or involving medical or clinical treatment must be performed by properly trained and qualified medical personnel and all traditional medical safeguards equipment and procedures that are appropriate in the particular situation to prevent serious injury or death should always continue to be used when National Instruments products are being used National Instruments products are NOT intended to be a substitute for any form of established process procedure or equipment used to monitor or safeguard human health and safety in medical or clinical treatment Table of Contents About This Manual How to Use This Manual S et vccccsescssesnseeoseces ares tes a e N N O TEE xi Organization of This Manual eee ceeceseeeeceseeeeceeeeeeseeeeseecaecaaecaecsaesae
5. Wr Te ENDON EAER Bute SS C seit Eos Load Set ros eyte 9 Check to automatically configure the bus to hardware interface association Figure 6 3 Help Frame in NI 488 Config Global Frame The Interface Type pop up menu options let you switch the checkboxes among interface types Choose NuBus boards for boards such as the NB GPIB P TNT or NB GPIB P installed in a NuBus Macintosh The Serial box products option applies to the GPIB 422CT or GPIB 232CT A the Ethernet box products option applies to the GPIB ENET and the SCSI box products option applies to the GPIB SCSI or GPIB SCSI A For specific information on configuring one of those products refer to the getting started manual that came with the product To the upper right of the Interface Type menu box is a row of interface checkboxes with which you can associate an IEEE 488 bus Slot numbers appear above the checkboxes and associated bus numbers if any appear below the checkboxes To manually associate a bus with an interface first unselect Auto Configure When you select an interface checkbox with Auto Configure selected the next available bus is assigned to it Figure 6 4 shows the manual association of bus 0 to System slot 3 NuBus slot xB National Instruments Corporation 6 5 NI 488 2 User Manual for MacOS Chapter 6 GPIB Configuration Utility Bus Device Frame N1488 Config National Instruments GPIB Configuration Ut
6. Writing Your NI 488 Application Items to Include This section discusses items you should include in your application program general program steps and an NI 488 example In this manual the example code is presented in C using the standard C language interface The NI 488 2 software includes the source code for example NI 488 applications written in C Devsamp c and in FutureBASIC Devsamp bas Include the following in your application program e For C applications include the GPIB header files decl h These files contain variable and constant declarations as well as declarations of structures e For FutureBASIC applications the files FutureBASIC GPIB LI GLBL and FutureBASIC GPIB LI LIB must be included at the beginning of your program e Check for errors after each NI 488 function call e Declare and define a function to handle GPIB errors This function takes the device offline and closes the application If the function is declared as follows void gpiberr char msg function prototype then your application invokes the function as follows if ibsta amp ERR gpiberr GPIB error NI 488 2 User Manual for MacOS 2 6 National Instruments Corporation Chapter 2 Developing Your Application NI 488 Program Shell Figure 2 1 is a flowchart of the steps to create your application program using device level NI 488 functions Open Device ibdev Are All Devices Open Yes lt lt
7. IBIC 488 2 Simply issue the same functions or routines one at a time as they appear in your application program Because IBIC 488 2 returns the status values and error codes after each call you should be able to determine which GPIB call is failing For more information about IBIC 488 2 refer to Chapter 4 Interface Bus Interactive Control Utility National Instruments Corporation 3 1 NI 488 2 User Manual for MacOS Chapter 3 Debugging Your Application After you determine which GPIB call is failing and note the corresponding values of the global variables refer to Appendix A Status Word Conditions and Appendix B Error Codes and Solutions These appendixes will help you interpret the state of the driver GPIB Error Codes Table 3 1 lists the GPIB error codes Remember that the error variable is meaningful only when the ERR bit in the status variable is set For a detailed description of each error and possible solutions refer to Appendix B Error Codes and Solutions Table 3 1 GPIB Error Codes Error iberr Mnemonic Value Meaning EDVR 0 System error ECIC 1 Function requires GPIB board to be CIC ENOL 2 No Listeners on the GPIB EADR 3 GPIB board not addressed correctly EARG 4 Invalid argument to function call ESAC 5 GPIB board not System Controller as required EABO 6 T O operation aborted timeout ENEB 7 Nonexistent GPIB board EDMA 8 No DMA channel available EOIP 10 Asynch
8. Make a Device Level Call e Send Data to Device ibwrt e Receive Data from Device ibrd e Clear Device ibclr Serial Poll Device ibrsp and so on Finished GPIB Programming Close Device ibon1 Closed All Devices Figure 2 1 General Program Shell Using NI 488 Device Functions National Instruments Corporation 2 7 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application General Program Steps and Examples The following steps demonstrate how to use the NI 488 device functions in your program This example configures a digital multimeter reads 10 voltage measurements and computes the average of these measurements Step 1 Open a Device Your first NI 488 function call should be to ibdev to open a device ud ibdev 0 1 0 T10s 1 0 if ibsta amp ERR gpiberr ibdev error The input arguments of the ibdev function are as follows e 0Q board index for GPIBO e 1 primary GPIB address of the device e 0 no secondary GPIB address for the device e T10s I O timeout value 10 s e 1 send END message with the last byte when writing to device e 0Q disable EOS detection mode When you call ibdev the driver automatically initializes the GPIB by sending an Interface Clear IFC message and placing the device in remote programming state Step 2 Clear the Device Clear the device before you configure the device for your application Clearing the devi
9. One way IBIC 488 2 helps you to learn about your instrument and to troubleshoot problems is by displaying the following information on your screen whenever you enter a command e The results of the status word ibsta in hexadecimal notation e The mnemonic constant of each bit set in ibsta e The mnemonic value of the error variable iberr if an error exists the ERR bit is set in ibsta e The count value for each read write or command function e The data received from your instrument Example Using NI 488 Functions This section shows how you might use IBIC 488 2 to test a sequence of NI 488 device function calls You do not need to remember the parameters that each function takes If you enter the function name only IBIC 488 2 prompts you for the necessary parameters National Instruments Corporation 4 1 NI 488 2 User Manual for MacOS Chapter 4 Interface Bus Interactive Control Utility 1 Run IBIC 488 2 by double clicking on the IBIC 488 2 icon Your screen should appear as follows IBIC 488 2 out NI 488 2 User Manual for MacOS National Instruments IEEE 488 2 Interface Bus Interactive Control Program IBIC For the Macintosh Family of Computers 091987 1995 National Instruments Corp Version 6 0 All Rights Reserved Use ibdev to open a device assign it to access board gpibo choose a primary address of 6 with no secondary address set a timeout of 10 s enable
10. Read s n rdbuf Output gt Read 10 98E 3 sum AsciiToFloat rdbuf Step 7 Process the Data Repeat steps 4 through 6 in a loop until 10 measurements have been read Then print the average of the readings as shown printf The average of the 10 readings is f n sum 10 0 Step 8 Place the Device Offline As a final step take the device offline using the ibon1 function ibonl ud 0 National Instruments Corporation 2 11 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application Writing Your NI 488 2 Application Items to Include This section discusses items you should include in an application program that uses NI 488 2 routines general program steps and an NI 488 2 example In this manual the example code is presented in C using the standard C language interface The NI 488 2 software includes the source code for example NI 488 2 applications written in C Samp4882 c and FutureBASIC Samp4882 bas Include the following in your application program NI 488 2 User Manual for MacOS For C applications include the GPIB header files decl h These file contain variable and constant declarations as well as declarations of structures For FutureBASIC applications the file FutureBASIC GPIB LI GLBL and FutureBASIC GPIB LI LIB must be included at the beginning of your program Check for errors after each NI 488 2 routine Declare and define a function to handle GPIB erro
11. except that WaitSRQ suspends the application program until either SRQ is asserted or the timeout period is exceeded The following examples use NI 488 2 routines to detect SRQ and then determine which device requested service In these examples three devices are present on the GPIB at addresses 3 4 and 5 and the GPIB interface is designated as bus index 0 The first example uses FindROS to determine which device is requesting service and the second example uses AllSpo11 to serial poll all three devices Both examples use WaitSRQ to wait for the GPIB SRQ line to be asserted Note Automatic serial polling is not used in these examples because you cannot use it with NI 488 2 routines National Instruments Corporation 5 9 NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques Example 1 Using FindRQS This example illustrates the use of FindRQS to determine which device is requesting service void GetASerialPollResponse char DevicePad char DeviceResponse char SerialPollResponse 0 int WaitResult Addr4882_t Addrlist 4 WaitSRQ 0 if WaitResult 3 4 5 NOADDR amp WaitResult printf SRQ is asserted n Use FindRQS to find a device that requested servic ets FindROQS 0 AddrList amp SerialPollResponse if ibsta amp ERR printf Device at pad x returned byte x n AddrList ibcnt int SerialPollResponse DevicePad AddrList
12. 30 hex 1E The primary GPIB address of any device is set within that device either with hardware switches or in some cases a software program This address must match the address listed in the configuration utility Refer to the device documentation for instructions about the device address The primary GPIB address of all NI 488 2 driver buses is 0 unless changed by the configuration utility There are no hardware switches on the interface board to select the GPIB address Use the Primary Address pop up menu to select the primary address of the bus or device Secondary Address You must assign a secondary address in the range decimal 96 hex 60 to decimal 126 hex 7E to any device or bus using secondary addressing As with primary addressing the secondary GPIB address of any device is set within that device either with hardware switches or in some cases a software program This address must match the address listed in the configuration utility Refer to your device documentation for instructions By default secondary addressing is disabled for all devices and boards unless you change it with the configuration utility Select the secondary address of the bus or device from the Secondary Address pop up menu The secondary addresses are displayed in three formats zero based decimal and hexadecimal Only the zero based format is displayed in the pop up menu box Selecting None means that only primary addressing is used for this bus or
13. 4 1 and Table 4 2 summarize the syntax of NI 488 functions in IBIC 488 2 vrepresents a number and string represents a string that you input For more information about the function parameters use the IBIC 488 2 help feature or refer to the NI 488 2 Function Reference Manual for MacOS Table 4 1 Syntax for Board Level NI 488 Functions in IBIC 488 2 Syntax Description ibbna brdname Change access board of device where brdname is symbolic name of new board ibelr Clear specified device ibconfig mn v Alter configurable parameters where mn is mnemonic for a configuration parameter or equivalent integer value ibdev v v v v v Open an unused device ibdev parameters are board id pad v sad tmo eos eot ibeos v Change disable EOS message ibeot v Enable disable END message iblines Read the state of all GPIB control lines ibln v v Check for presence of device on the GPIB at pad sad ibloc Go to local ibonl v Place device online or offline ibpad v Change primary address ibpct Pass control ibppe v Parallel poll configure ibrd v Read data where v is the bytes to read ibrda v Read data asynchronously where v is the bytes to read NI 488 2 User Manual for MacOS 4 6 National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility Table 4 1 Syntax for Board Level NI 488 Functions in IBIC 488 2 Continued Syntax Description ibrdf flnam
14. 6 10 EOS Byte option 6 9 to 6 10 NI 488 2 User Manual for MacOS Index EOS modes 6 9 exiting 6 12 global frame 6 5 to 6 6 help frame 6 4 to 6 5 Interface Type menu 6 2 opening 6 1 to 6 2 opening screen illustration 6 2 overview 6 1 Primary Address pop up menu 6 8 Rename Device option 6 11 Repeat Addressing option 6 9 Secondary Address pop up menu 6 8 System Controller option 6 11 Timeout pop up menu 6 9 TNT High Speed option 6 10 Unaddressing option 6 11 Use Bus option 6 12 NI 488 functions board functions 2 2 device functions 2 2 one device per board concept 2 1 to 2 2 parallel polling 5 11 to 5 14 serial polling 5 5 to 5 8 using in IBIC 488 2 ibdev 4 12 to 4 14 ibrd 4 14 ibwrt 4 14 syntax table 4 6 to 4 9 NI 488 2 applications programming See programming NI 488 2 routines capabilities 2 2 parallel polling 5 13 to 5 14 serial polling 5 9 serial polling examples AllSpoll 5 11 FindRQS 5 10 using in IBIC 488 2 Receive 4 16 Send 4 15 NI 488 2 User Manual for MacOS SendList 4 15 Set 4 15 syntax table 4 9 to 4 10 NI 488 2 software C language files 1 8 default configuration 6 3 driver and driver utilities 1 7 FutureBASIC language files 1 8 NI 488 2 Test utility 3 1 to 3 2 NRFD not ready for data line 1 3 number syntax IBIC 488 2 4 5 0 operation of GPIB See GPIB operation P parallel polling 5 11 to 5 14 implementing 5 11 to 5 14 using NI 488 func
15. Corporation xi NI 488 2 User Manual for MacOS About This Manual Use the NI 488 2 Function Reference Manual for MacOS for specific NI 488 function and NI 488 2 routine information such as format parameters and possible errors Organization of This Manual This manual is organized as follows NI 488 2 User Manual for MacOS Chapter 1 Introduction gives an overview of GPIB and the NI 488 2 software Chapter 2 Developing Your Application explains how to develop a GPIB application program using NI 488 functions and NI 488 2 routines Chapter 3 Debugging Your Application describes several ways to debug your application program Chapter 4 Interface Bus Interactive Control Utility introduces you to IBIC 488 2 the interactive control utility you can use to communicate with GPIB devices interactively Chapter 5 GPIB Programming Techniques describes techniques for using some NI 488 functions and NI 488 2 routines in your application program Chapter 6 GPIB Configuration Utility contains instructions for configuring the NI 488 2 software with the NI 488 Config utility Appendix A Status Word Conditions gives a detailed description of the conditions reported in the status word ibsta Appendix B Error Codes and Solutions lists a description of each error some conditions under which it might occur and possible solutions Appendix C Customer Communication contains forms you can use to request help from Nation
16. Device Level NI 488 Functions in IBIC 488 2 eee 4 7 Table 4 3 Syntax for NI 488 2 Routines in IBIC 488 2 000 0 eee eeeeeeseceeeeceteeeneeeees 4 9 Table 4 4 Auxiliary Functions in IBIC 488 2 ooo eecceeeeeeeereeseeceesseceenaeenees 4 16 Table 6 1 Bus Device Options in NI 488 Config oo eee eeeceeceseeneceeeeseeneees 6 7 Table A 1 Stats Word Bits receten Sex eaeoe e aE E EE Eae ar aiai A 1 Table B 1 GPIB Error CdS os sivcccseeceuns catsecunsveeavs n a a a Gs B 1 NI 488 2 User Manual for MacOS X National Instruments Corporation About This Manual This manual describes the features and functions of the NI 488 2 software for MacOS This manual assumes that you are already familiar with the Macintosh operating system How to Use This Manual Set SSS Getting Started Manual Installation and Configuration Novice Experienced Users Users y SSeS NI 488 2 Function NI 488 2 Application Reference Manual User Manual for Development for MacOS MacOS and Examples Function and Routine Descriptions Use the getting started manual that came with your kit to install and configure your GPIB hardware and NI 488 2 software Use the NI 488 2 User Manual for MacOS to learn the basics of GPIB and how to develop an application program The user manual also contains debugging information and detailed examples National Instruments
17. In Charge CIC The only argument of SendIFC is the GPIB interface board number SendIFC 0 if ibsta amp ERR gpiberr SendIFC error Step 2 Find All Listeners Use the FindLstn routine to create an array of all of the instruments attached to the GPIB The first argument is the interface board number the second argument is the list of instruments that was created the third argument is a list of instrument addresses that the procedure actually found and the last argument is the maximum number of devices that the procedure can find that is it must stop if it reaches the limit The end of the list of addresses must be marked with the NOADDR constant which is defined in the header file that you included at the beginning of the program for loop 0 loop lt 30 loop t instruments loop loop instruments 31 NOADDR printf Finding all Listeners on the bus n Findlstn 0 instruments result 30 if ibsta amp ERR gpiberr FindLstn error NI 488 2 User Manual for MacOS 2 14 National Instruments Corporation Chapter 2 Developing Your Application Step 3 Identify the Instrument Send an identification query to each device for identification For this example assume that all of the instruments are IEEE 488 2 compatible and can accept the identification query IDN In addition assume that FindLstn found the GPIB interface board at primary address 0 default and therefo
18. MacOS 6 6 National Instruments Corporation Chapter 6 GPIB Configuration Utility For information on product specific options such as the Serial or IP Address pop up boxes refer to the getting started manual that came with your GPIB hardware Table 6 1 Bus Device Options in NI 488 Config Option Type Default Setting Primary Address Bus Device 0 Secondary Address Bus Device None Timeout Bus Device 10 sec Read END on EOS Bus Device Disabled Write END on EOS Bus Device Disabled Write END on Last Byte Bus Device Enabled 8 bit EOS Bus Device Disabled EOS Byte Bus Device 0 Bus Timing Bus Only Interface specific TNT High Speed Bus Only Disabled DMA Bus Only Disabled System Controller Bus Only Enabled Assert REN when System Bus Only Enabled Unaddressing Bus Only Disabled Repeat Addressing Bus Device Disabled Rename Device Device Only dev 1 dev64 Use Bus Device Only gpib0 National Instruments Corporation 6 7 NI 488 2 User Manual for MacOS Chapter 6 GPIB Configuration Utility Options for Buses or Devices Select the device or bus you want to configure from the Bus Device pop up menu The following sections describe the options available for buses or devices Also refer to the subsequent sections Options for Buses Only and Options for Devices Only Primary Address Each device and bus must have unique primary addresses in the range decimal 0 to decimal
19. TE S EEE E EEE RE aarete 4 4 Number Syntax anenee E EE E A E ER R 4 5 Sting Syntax aoa A a E Rae ea E es 4 5 Address S VOTAK adn ccscesceesslvcesossettveerandesdyeesvbcesspsvecseesis ssiepesesnsuvcpeoseeesdensutcetepaueuves 4 5 IBIC 488 2 Syntax for NI 488 Functions o00 ee eee eeeeseeseecseceseeseceseeseceseeseeeeeseeseeeenes 4 6 IBIC 488 2 Syntax for NI 488 2 Routines eee ee ceeceseeeeceeeeeceseeseeeeeeeeseeeeseseeeeneeeaes 4 9 Status Wordissa Ghani dn eae eich han ie Ras 4 11 Error nformat ON eee ee pa eacedeeens a tat ple sadend nei dotnet 4 11 COUN R E EE E E A EOE AAE EA A E EAS EEE diel dts 4 12 Common NI 488 Functions cccscccessecessssecsssececescecesececesaeceeacesesaeceseeaeessneeeseaeeseeeees 4 12 loe e E E A EE EEE E E EE a a ei i et 4 12 VOW m AEAEE ANES EPEA EE E EEEE E E EEEIEE ETE OE 4 14 Ploan P aE EEEE EEE A A EE E E 4 14 Common NI 488 2 Routines in IBIC 488 2 0 0 0 ccccceccssscceessseecsesececsneeccesaeeecneaeeeeseeeenes 4 15 SEB E E beseech seeks esa des eos bebe deee ate heel Gab aca dar eed bee deeb eet ede oat 4 15 Send and SenGLASt jcee20ssc2 feltt seeded docieceaesdersta tee ergdesns colts tnaddegecieetedetei east 4 15 RECEIVE se ithe nents anak E TEENE EaR EE 4 16 AUX ary PUDCHONS rsss e a E E E E E EE E beeen abetted 4 16 Set Select Device or Board ccccccessssecesseceeesceeessecesesaeeceeeeeeesaeeeseaeeesneeeeneaes 4 17 Help Display Help Information 00 eee eeeeeseeseeceseec
20. a mode in which the END bit is set only when EOI is asserted In this mode if the I O operation completes because of the EOS character by itself END is not set The application should check the last byte of the received buffer to see if it is the EOS character RQS dev SRQI indicates that a GPIB device is requesting service SRQI is set whenever the GPIB board is CIC the GPIB SRQ line is asserted and the automatic serial poll capability is disabled SRQI is cleared either when the GPIB board ceases to be the CIC or when the GPIB SRQ line is unasserted RQS appears in the status word only after a device level call and indicates that the device is requesting service RQS is set whenever bit 6 is asserted in the serial poll status byte of the device The serial poll that obtains the status byte can be the result of a call to ibrsp or the poll might be automatic if automatic serial polling is enabled Do not issue an ibwait on RQS for a device that does not respond to serial polls RQS is cleared when an ibrsp reads the serial poll status byte that caused the RQS CMPL dev brd CMPL indicates the condition of I O operations It is set whenever an T O operation is complete CMPL is cleared while the I O operation is in progress National Instruments Corporation A 3 NI 488 2 User Manual for MacOS Appendix A Status Word Conditions LOK brd REM brd LOK indicates whether the board is in a lockout state While L
21. bytes Following are some possible solutions e Verify that the instrument is operating correctly e Check for loose or faulty cabling or several powered off instruments on the GPIB e Ifthe timeout period is too short for the driver to send command bytes increase the timeout period National Instruments Corporation B 7 NI 488 2 User Manual for MacOS Appendix B Error Codes and Solutions ESTB 15 Solutions ESRQ 16 ESTB is reported only by the ibrsp function ESTB indicates that one or more serial poll status bytes received from automatic serial polls have been discarded because of a lack of storage space Several older status bytes are available however the oldest is being returned by the ibrsp call Following are some possible solutions e Call ibrsp more frequently to empty the queue e Disable autopolling with the ibconfig function or the NI 488 Config utility Solutions NI 488 2 User Manual for MacOS ESRQ occurs only during the ibwait function or the wait SRQ routine ESRQ indicates that a wait for RQS is not possible because the GPIB SRQ line is stuck on This situation can be caused by the following events e Usually a device unknown to the software is asserting SRQ Because the software does not know of this device it can never serial poll the device and unassert SRQ e A GPIB bus tester or similar equipment might be forcing the SRQ line to be asserted e A cable problem might exist invo
22. bytes SendDataBytes addrlist string Send data bytes mode SendIFC Send interface clear SendList addrlist string mode Send data to multiple devices SendLLO Put devices in local lockout SendSetup addrlist Send setup SetRWLS addrlist Put devices in remote with lockout state TestSys addrlist Cause multiple devices to perform self tests TestSRQ Test for service request Trigger address Trigger a device TriggerList addrlist Trigger multiple devices WaitSRQ Wait for service request NI 488 2 User Manual for MacOS 4 10 National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility Status Word In IBIC 488 2 all NI 488 functions except ibfind and ibdev and NI 488 2 routines return the status word ibsta in two forms a hex value in square brackets and a list of mnemonics in parentheses In the following example the status word is on the second line It shows that the device function write operation completed successfully udO ibwrt f2t3x 0100 cmpl count 5 udo For more information about the status word refer to Chapter 2 Developing Your Application Error Information If an NI 488 function or NI 488 2 routine completes with an error IBIC 488 2 displays the relevant error mnemonic In the following example an error condition EBUS has occurred during a data transfer udO ibwrt f2t3x 8100 err cmpl error EBUS count 1 udo In this example the addressing command bytes could not b
23. can function as a Talker Listener and Controller National Instruments Corporation 1 1 NI 488 2 User Manual for MacOS Chapter 1 Introduction Controller In Charge and System Controller GPIB Addressing You can have multiple Controllers on the GPIB but only one Controller at a time can be the active Controller or Controller In Charge CIC When a Controller is not active it is considered an idle Controller Active control can pass from the current CIC to an idle Controller The System Controller usually a GPIB interface board is the only device on the bus that can make itself the CIC All devices and boards connected to the GPIB must be assigned a unique GPIB address The Controller uses the addresses to identify each device when sending or receiving data A GPIB address is made up of two parts a primary address and an optional secondary address The primary address is a number in the range 0 to 30 The GPIB Controller uses the primary address to form a talk or listen address that is sent over the GPIB when communicating with a device A talk address is formed by setting bit 6 the TA Talk Active bit of the GPIB address A listen address is formed by setting bit 5 the LA Listen Active bit of the GPIB address For example if a device is at address 1 the Controller sends hex 41 address 1 with bit 6 set to make the device a Talker Because the Controller is usually at primary address 0 it sends hex 20 address 0 with bi
24. codes and solutions GPIB operation addressing 1 2 configuration controlling more than one board 1 5 linear and star configuration illustration 1 5 requirements 1 6 to 1 7 Controller In Charge and System Controller 1 2 interface management lines ATN attention 1 4 EOI end or identify 1 4 IFC interface clear 1 4 NI 488 2 User Manual for MacOS Index REN remote enable 1 4 SRQ service request 1 4 overview 1 1 sending messages 1 3 to 1 4 signals and lines data lines 1 3 DAV data valid 1 3 handshake lines 1 3 NDAC not data accepted 1 3 NRFD not ready for data 1 3 Talkers Listeners and Controllers 1 1 GPIB programming techniques device level calls and bus management 5 4 high speed data transfers 5 2 to 5 4 enabling HS488 5 2 to 5 3 system configuration effects 5 3 parallel polling 5 11 to 5 14 implementing 5 11 to 5 14 using NI 488 functions 5 12 to 5 13 using NI 488 2 routines 5 13 to 5 14 serial polling 5 5 to 5 9 automatic serial polling 5 6 to 5 8 autopolling and interrupts 5 7 C ON SRQ capability 5 8 stuck SRQ state 5 7 service requests from IEEE 488 devices 5 6 from IEEE 488 2 devices 5 6 SRQ and serial polling with NI 488 device functions 5 8 with NI 488 2 routines 5 9 Talker Listener applications 5 5 requesting service 5 5 waiting for messages from Controller 5 5 termination of data transfers 5 1 to 5 2 waiting for GPIB conditions 5 4 NI 488 2 User Ma
25. function to send data and the Controller uses it to send commands See acceptor handshake and handshake Serial Poll Disable is the GPIB command used to cancel an SPE command Serial Poll Enable is the GPIB command used to enable a specific device to be polled That device must also be addressed to talk See SPD The GPIB line that a device asserts to notify the CIC that the device needs servicing To load the operating system programs from floppy or hard disk into memory and to begin executing the code A hard boot is when power is applied to the computer The IEFE 488 2 defined data byte sent by a device when it is serially polled See ibsta The single designated Controller that can assert control become CIC of the GPIB by sending the Interface Clear IFC message Other devices can become CIC only by having control passed to them National Instruments Corporation G 7 NI 488 2 User Manual for MacOS Glossary T TAD Talk Address Talker TCT timeout TLC TTL U ud unit descriptor UNL UNT NI 488 2 User Manual for MacOS See MTA A GPIB device that sends data messages to Listeners Take Control is the GPIB command used to pass control of the bus from the current Controller to an addressed Talker A feature of the NI 488 2 driver that prevents I O functions from hanging indefinitely when there is a problem on the GPIB An integrated circuit that implements most of the GPIB Talker Listen
26. is running If your application uses ibconfig it will always work regardless of the previous configuration of the driver Refer to the description of ibconfig in the NI 488 2 Function Reference Manual for MacOS for more information Timing Errors If your application fails but the same calls issued in ibic are successful your program might be issuing the NI 488 2 calls too quickly for your device to process and respond to them This problem can also result in corrupted or incomplete data A well behaved IEEE 488 device should hold off handshaking and set the appropriate transfer rate If your device is not well behaved you can National Instruments Corporation 3 3 NI 488 2 User Manual for MacOS Chapter 3 Debugging Your Application test for and resolve the timing error by single stepping through your program and inserting finite delays between each GPIB call One way to do this is to have your device communicate its status whenever possible Although this method is not possible with many devices it is usually the best option Your delays will be controlled by the device and your application can adjust itself and work independently on any platform Other delay mechanisms will probably cause varying delay times on different platforms Communication Errors Repeat Addressing Some devices require GPIB addressing before any GPIB activity Devices adhering to the IEEE 488 2 standard should remain in their current state until spe
27. of your devices are powered on e Call ibpad or ibsad if necessary to match the configured address to the device switch settings e Reduce the write byte count to that which is expected by the Controller National Instruments Corporation B 3 NI 488 2 User Manual for MacOS Appendix B Error Codes and Solutions EADR 3 Solutions EARG 4 EADR occurs when the GPIB board is CIC and is not properly addressing itself before read and write functions This error is usually associated with board level functions EADR is also returned by the function ibgts when the shadow handshake feature is requested and the GPIB ATN line is already unasserted In this case the shadow handshake is not possible and the error is returned to notify you of that fact Following are some possible solutions e Make sure that the GPIB board is addressed correctly before calling ibrd ibwrt RcvRespMsg or SendDataBytes e Avoid calling ibgts except immediately after an ibcmd call ibcmd causes ATN to be asserted Solutions NI 488 2 User Manual for MacOS EARG results when an invalid argument is passed to a function call The following are some examples e ibtmo called with a value not in the range 0 through 17 e ibpad or ibsad called with invalid addresses e ibppc called with invalid parallel poll configurations e A board level NI 488 call made with a valid device descriptor or a device level NI 488 call made with a board descri
28. of a key on the keyboard for example lt Shift gt IEEE 488 and IEEE 488 2 refer to the ANSI IEEE Standard 488 1 1987 and the ANSI IEEE Standard 488 2 1987 respectively which define the GPIB Macintosh refers to any computer using MacOS Abbreviations acronyms metric prefixes mnemonics symbols and terms are listed in the Glossary Related Documentation The following documents contain information that you may find helpful as you read this manual e ANSI IEEE Standard 488 1 1987 IEEE Standard Digital Interface for Programmable Instrumentation e ANSI IEEE Standard 488 2 1987 IEEE Standard Codes Formats Protocols and Common Commands e Inside Macintosh Apple Computer Inc Reading MA 1987 e Macintosh Programmer s Workshop Version 3 3 Apple Computer Inc Cupertino CA 1993 National Instruments Corporation xiii NI 488 2 User Manual for MacOS About This Manual e Metrowerks CodeWarrior User s Guide Metrowerks Inc Mooers NY e FutureBASIC STAZ Software Inc Diamondhead MS 1996 e THINK C User s Manual Symantec Corp Bedford MA Customer Communication NI 488 2 User Manual for MacOS National Instruments wants to receive your comments on our products and manuals We are interested in the applications you develop with our products and we want to help if you have problems with them To make it easy for you to contact us this manual contains comment and configuration forms for you to
29. the END message and disable the EOS mode ibdev enter enter enter enter enter enter board index 0 primary address 6 secondary address 0 timeout 13 EOI on last byte flag end of string mode byte id 32256 udo 1 0 You could also input all the same information with the ibdev command as follows ibdev 0 6 0 13 1 0 id 32256 udo 4 2 National Instruments Corporation National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility Clear the device as follows udO ibclr 0100 cmp1 Write the function range and trigger source instructions to your device Refer to the instrument s user manual for the command bytes that work with your instrument ud0 ibwrt enter string RST VAC AUTO TRIGGER 2 SRE 16 0100 cmp1 count 35 or ud0 ibwrt RST VAC AUTO TRIGGER 2 SRE 16 0100 cmpl count 35 Trigger the device as follows ud0 ibtrg 0100 cmpl Wait for a timeout or for your device to request service If the current timeout limit is too short use ibtmo to change it Use the ibwait command as follows ud0 ibwait enter wait mask TIMO ROS 0900 rqs cmpl or ud0 ibwait TIMO RQS 0900 rqs cmpl Read the serial poll status byte This serial poll status byte varies depending on the device used ud0 ibrsp 0100 cmpl Poll 0x40 decimal 64 4 3 NI 488 2 User Manual for MacOS Chapter 4
30. the count variables reflect the number of bytes sent In your application program you can use the count variables to null terminate an ASCII string of data received from an instrument For example if data is received in an array of characters you can use ibcnt to null terminate the array and print the measurement on the screen as follows char rdbuf 512 ibra ud rdbut 20L if ibsta amp ERR rdbuf ibcnt 0O printf Read s n rdbuf else error ibcnt is the number of bytes received Data begins in the array at index zero 0 therefore ibcnt is the position for the null character that marks the end of the string National Instruments Corporation 2 5 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application Using IBIC 488 2 to Communicate with Devices Before you begin writing your application program you might want to use the Interface Bus Interactive Control utility IBIC 488 2 With IBIC 488 2 you communicate with your instruments from the keyboard rather than from an application program Before you develop your GPIB application you can use IBIC 488 2 to learn how to communicate with your instruments and to determine your programming needs For specific device communication instructions refer to the user manual that came with your instrument For information about using IBIC 488 2 and for detailed examples refer to Chapter 4 Interface Bus Interactive Control Utility
31. the last byte of a write operation and has EOS characters disabled include decl h char ppr dev ibdev 0 3 0 T3s 1 0 Pass the binary bit pattern 0110 110 or hex 66 to ibppc ibppc dev 0x66 If the GPIB interface board configures itself for a parallel poll you should still use the ibppc function Pass the board index or a board unit descriptor value as the first argument in ibppc In addition if 5 12 National Instruments Corporation Chapter 5 GPIB Programming Techniques the individual status bit ist of the board needs to be changed use the ibist function In the following example the GPIB board is to configure itself to participate in a parallel poll It asserts DIOS when ist 1 if a parallel poll is conducted ibppc 0 Ox6C ibist 0 1 Conduct the parallel poll using ibrpp and check the response for a certain value The following example code performs the parallel poll and compares the response to hex 10 which corresponds to DIOS If that bit is set the ist of the device is 0 ibrpp dev amp ppr if ppr amp 0x10 printf ist O n Unconfigure the device for parallel polling with ibppc Notice that any value having the parallel poll disable bit set bit 4 in the bit pattern disables the configuration so you can use any value between hex 70 and 7E ibppc dev 0x70 Parallel Polling with NI 488 2 Routines Follow these steps to implement parallel polling using NI 488 2
32. unless you have a National Instruments GPIB ENET National Instruments Corporation 3 5 NI 488 2 User Manual for MacOS Chapter 3 Debugging Your Application How do I use IBIC 488 2 You can use IBIC 488 2 to practice communication with your instrument troubleshoot problems and develop your application program For instructions refer to Chapter 4 Interface Bus Interactive Control Utility How can I determine which type of GPIB board I have installed Run the NI Boards configuration utility for information about the GPIB boards installed in your computer What information should I have before I call National Instruments Before you contact National Instruments note the results of the diagnostic test NI 488 2 Test and fill out the support forms in Appendix C Customer Communication NI 488 2 User Manual for MacOS 3 6 National Instruments Corporation Chapter Interface Bus Interactive Control Utility This chapter introduces you to IBIC 488 2 the interactive control utility you can use to communicate with GPIB devices interactively Overview With the IBIC 488 2 utility you communicate with GPIB devices through functions you enter at the keyboard For specific information about how to communicate with your particular device refer to the manual that came with the device You can use IBIC 488 2 to practice communication with the instrument troubleshoot problems and develop your application program
33. write National Instruments Corporation 5 1 NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques e EOS read method TIf this is enabled the NI 488 2 driver terminates ibrd ibrda and ibrdf calls when the EOS byte is detected on the GPIB when the GPIB EOI line is asserted or when the specified count is reached If the EOS read method is disabled ibrd ibrda and ibrdf calls terminate only when the GPIB EOI line is asserted or the specified count has been read You can use the ibconfig function to configure the software to inform you whether or not the GPIB EOI line was asserted when the EOS byte was read Use the IbcEndBitIsNormal option to configure the software to report only the END bit in ibsta when the GPIB EOI line is asserted By default the NI 488 2 driver reports END in ibsta when either the EOS byte is read in or the EOI line is asserted during a read High Speed Data Transfers HS488 National Instruments has designed a high speed data transfer protocol for IEEE 488 called HS488 This protocol increases performance for GPIB reads and writes up to 8 MB s depending on the speed of your computer HS488 is a superset of the IEEE 488 standard thus you can mix IEEE 488 1 IEEE 488 2 and HS488 devices in the same system If HS488 is enabled the TNT4882C hardware implements high speed transfers automatically when communicating with HS488 instruments If you attempt to enable HS488 on a GPIB board
34. 03 k kilo 10 M Mega 10 A AC acceptor handshake access board ANSI ASCII automatic serial polling autopolling alternating current Listeners use this GPIB interface function to receive data and all devices use it to receive commands See source handshake and handshake The GPIB board that controls and communicates with the devices on the bus that are attached to it American National Standards Institute American Standard Code for Information Interchange A feature of the NI 488 2 software in which serial polls are executed automatically by the driver whenever a device asserts the GPIB SRQ line National Instruments Corporation G 1 NI 488 2 User Manual for MacOS Glossary board level function boot C CFE CFGn CIC configuration Controller In Charge CIC CPU D DAV Data Valid DCL dec Device Clear device level function DIO1 through DIO8 NI 488 2 User Manual for MacOS A rudimentary function that performs a single operation See startup Configuration Enable is the GPIB command which precedes CFGn and is used to place devices into their configuration mode These GPIB commands CFG1 through CFG15 follow CFE and are used to configure all devices for the number of meters of cable in the system so that HS488 transfers occur without errors See Controller In Charge The process of altering the software parameters in the driver that desc
35. 1 4 interface management lines table 1 4 NDAC not data accepted 1 3 NRFD not ready for data 1 3 REN remote enable 1 4 SRQ service request 1 4 SRQ service request line definition 1 4 serial polling automatic serial polling 5 6 to 5 7 C ON SRQ capability 5 8 stuck SRQ state 5 7 using NI 488 device functions 5 8 using NI 488 2 routines 5 9 SRQI status word condition A 3 status word ibsta ATN A 4 CIC A 4 CMPL A 3 DCAS A 5 DTAS A 5 END A 2 to A 3 ERR A 2 IBIC 488 2 operation 4 11 LACS 5 5 A 5 NI 488 2 User Manual for MacOS l 8 list of status word bits table 2 4 A 1 to A 2 LOK A 4 REM A 4 RQS A 3 SRQI A 3 TACS 5 5 A 5 testing for ibsta conditions 2 3 to 2 4 TIMO A 2 string syntax IBIC 488 2 4 4 to 4 5 stuck SRQ state 5 7 syntax IBIC 488 2 See IBIC 488 2 System Controller configuring in NI 488 Config utility 6 11 GPIB operation 1 1 T TACS status word condition definition A 5 waiting for message from Controller 5 5 Talker Listener applications definition 5 5 requesting service 5 5 waiting for messages from Controller 5 5 Talkers 1 1 technical support C 1 termination of data transfers debugging applications 3 4 GPIB programming techniques 5 1 to 5 2 TestSRQ routine 5 9 timeout value setting in NI 488 Config utility 6 9 timing errors 3 3 to 3 4 TIMO status word condition A 2 TNT High Speed option NI 488 Config utility 6 10 TNT4882C har
36. 2 9 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application Step 5 Wait for the Measurement After you trigger the device the RQS bit is set when the device is ready to send the measurement You can detect RQS by using the ibwait function The second parameter indicates what you are waiting for Notice that the ibwait function also returns when the I O timeout value is exceeded printf Waiting for RQS n ibwait ud TIMO RQS if ibsta amp ERR TIMO gpiberr ibwait error When SRQ has been detected serial poll the instrument to determine if the measured data is valid or if a fault condition exists For IEEE 488 2 instruments you can find out by checking the message available MAV bit bit 4 in the status byte that you receive from the instrument ibrsp ud amp StatusByte if ibsta amp ERR gpiberr ibrsp error if StatusByte amp MAVbit gpiberr Improper Status Byte printf Status Byte 0x x n StatusByte NI 488 2 User Manual for MacOS 2 10 National Instruments Corporation Chapter 2 Developing Your Application Step 6 Read the Measurement If the data is valid read the measurement from the instrument AsciiToFloat is a function that takes a null terminated string as input and outputs the floating point number it represents ibra ud rdbuf 10L if ibsta amp ERR gpiberr ibrd error rdbuf ibcntl 0 printf
37. 20 udO 10 Notice that the multiplier does not become part of the function name that is ibwrt Hello is repeated 20 times not 5 ibwrt Hello Execute Indirect File The function reads a specified file and executes the IBIC 488 2 functions listed in that file in sequence as if they were entered in that order from the keyboard The following example executes the IBIC 488 2 functions listed in the file userfile gpib0O userfile The following example repeats the operation three times gpib0O 3 userfile The display mode that is in effect before this function was executed can be changed by functions in the indirect file NI 488 2 User Manual for MacOS 4 18 National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility Buffer Set Buffer Display Mode You can set the type of display used for buffers to control how much of the buffer is displayed Type buffer 0 to turn off the display of all buffers buffer 1 to display the buffer in ASCII only buffer 2 to display the buffer in hex ASCII or buffer 3 to display a brief hex ASCII display National Instruments Corporation 4 19 NI 488 2 User Manual for MacOS Chapter GPIB Programming Techniques This chapter describes techniques for using some NI 488 functions and NI 488 2 routines in your application program For more detailed information about each function or routine refer to the NI 488 2 Function Referen
38. 3 the END message enabled eot 1 and the EOS mode disabled eos 0 ibdev 0 6 0x67 13 1 0 id 32256 udo NI 488 2 User Manual for MacOS 4 12 National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility If you use ibdev without specifying parameters IBIC 488 2 prompts you for the input parameters as shown in the following example ibdev enter board index 0 enter primary address 6 enter secondary address 0x67 enter timeout 13 enter EOI on last byte flag 1 enter end of string mode byte 0 id 32256 udo The following three distinct errors can occur with the ibdev call e EDVR No device is available the board index entered refers to a nonexistent board that is not 0 1 2 or 3 or no driver is installed The following example illustrates an EDVR error ibdev 4 6 0x67 7 1 0 id 1 8000 err error EDVR 2 e ENEB The board index entered refers to a known board such as 0 but the driver cannot find the board e EARG One of the last five parameters is an invalid value The ibdev call returns with a new prompt and the EARG error invalid function argument If the ibdev call returns with an EARG error you must identify which parameter is incorrect and use the appropriate command to correct it In the following example pad National Instruments Corporation 4 13 NI 488 2 User Manual for MacOS Chapter 4 ibwrt ibrd Interface Bus Interactive C
39. 488 2 calls acGPIB68k CodeWarrior lib isa library file for Metrowerks CodeWarrior compiler acGPIB68k ThinkC 1ib is a library file for THINK C compiler acGPIB68k o is a library file for MPW C compiler acGPIB shlb is a shared library for developing applications for PowerPC FutureBASIC Language Files The BASIC LI Folder contains the following files relevant to programming in FutureBASIC NI 488 2 User Manual for MacOS FutureBASIC GPIB LI lib is a library file loaded by your FutureBASIC program FutureBASIC GPIB L1 GLBLis a global file that must be included at the beginning of your program Devsamp bas is a device level sample program Samp4882 bas is a sample program using NI 488 2 calls 1 8 National Instruments Corporation Chapter 1 Introduction How the NI 488 2 Software Works with Your System The NI 488 2 INIT is a device driver that is loaded at system startup Figure 1 3 shows how the NI 488 2 software works with your system and your GPIB hardware IBIC 488 2 Utility for User Using NI 488 2 Application Commands Interactively Program NI 488 2 Language Interface Operating System NI 488 2 Driver GPIB Hardware Interface Figure 1 3 How the NI 488 2 Software Works with Your System National Instruments Corporation 1 9 NI 488 2 User Manual for MacOS Chapter Developing Your Application This chapter explains how t
40. 488 2 program also displays the status word and the count of transferred bytes 488 2 0 Receive 5 10 STOPend 2124 end cmpl cic lacs count 5 48 65 6c 6c 6f Hello Auxiliary Functions Table 4 4 summarizes the auxiliary functions that you can use in IBIC 488 2 Table 4 4 Auxiliary Functions in IBIC 488 2 Description set udname Select active device or board where udname is the symbolic name of the new device or board for example dev1 or gpib0 Call ibfind or ibdev initially to open each board or device help option Display help information where option is any NI 488 or NI 488 2 call If you do not enter an opt ion a menu of options appears Repeat previous function E Turn display off Turn display on n function Execute function n times where function represents the correct IBIC 488 2 function syntax n Execute previous function n times NI 488 2 User Manual for MacOS 4 16 National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility Table 4 4 Auxiliary Functions in IBIC 488 2 Continued Function Description filename Execute indirect file where filename is the pathname of a file that contains IBIC 488 2 functions to be executed print string Display string on screen where string is an ASCII character sequence octal bytes hex bytes or special symbols buffer Set the type of display used for buffer
41. Board 4 17 BASIC See FutureBASIC Buffer Set Buffer Display Mode function IBIC 488 2 4 19 bus device frame NI 488 Config utility bus only options 6 10 to 6 11 bus or device options 6 8 to 6 10 device only options 6 11 to 6 12 options table 6 7 Bus Timing option NI 488 Config utility 6 10 byte count IBIC 488 2 4 12 C C language compiling linking and running applications 2 19 to 2 20 NI 488 2 software language files 1 8 CIC protocol for making GPIB board Controller in Charge 5 4 CIC status word condition A 4 CMPL status word condition A 3 communication errors repeat addressing 3 4 termination method 3 4 compiling linking and running applications C applications 2 19 to 2 20 FutureBASIC applications 2 20 configuration See GPIB operation NI 488 Config utility NI 488 2 User Manual for MacOS Index configuration errors debugging 3 3 Configure Enable CFE message 5 3 Configure CFGn message 5 3 control items NI 488 Config utility 6 4 Controllers CIC protocol for making GPIB board Controller in Charge 5 4 Controller In Charge and System Controller 1 2 device level calls and bus management 5 4 GPIB operation 1 1 monitoring by Talker Listener applications 5 5 System Controller option NI 488 Config utility 6 11 count IBIC 488 2 4 12 count variables ibcnt and ibentl 2 5 customer communication xiv C 1 D data lines 1 3 data transfers high speed HS488 5 2 to 5 4 en
42. E CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporation NI 488 NI 488 2
43. E R 2 8 Step 3 Configure the Device sseeeseseeesseresesssrersreerrrrsreresreserrrereres 2 9 Step 4 Trigger the Device s r isi eee ceeeseeeeeseecneeseecaeeseceeeseeseeeaeeaee 2 9 Step 5 Wait for the Measurement 0 eee cece ceeeeeeeeeeeeseaeeneeeaes 2 10 Step 6 Read the Measurement 00 eee eee eeeesseseceseeseceeeeeeeseeeneeaee 2 11 Step 7 Process the Data 00 eee ceeeeceseeesceeeeseeseecaeceecesenseseeseneeaes 2 11 Step 8 Place the Device Offline eee cseeeeceseeeeceeeeeeeseeeneeaes 2 11 Writing Your NI 488 2 Application 0 0 eee cee ceseescesecescesecseeesecaeesecsaeesecereaeesaeeaeeaes 2 12 Tt ms to Include sis seis cc cssetss tape ssckesaes eea tits E EEKE EES 2 12 NI 488 2 Program Shellin e eee ded ines a r A E uo EN 2 13 General Program Steps and Examples sssessssesssseseerssssresesrsresrsreerssrererssrerrereee 2 14 Step 1 Initi lization ss coiere nni i essees eues 2 14 Step 2 Find All Listeners isesi inrer esiri 2 14 Step 3 Identify the Instrument 00 0 cece ceeeeeeeeeeeeesaeceeenaes 2 15 Step 4 Initialize the Instrument eee eee eeeeceeseceeceeeeseeeeeenee 2 16 Step 5 Configure the Instrument eee ceseeeeceeeeneeeeeneenees 2 16 Step 6 Trigger the Instrument 0 0 ee ee eee cseeseceeeeeceeeeeeeaecseenaee 2 17 Step 7 Wait for the Measurement oe cee eeeceeeeeeeeeeeeessecaeeaes 2 17 Step 8 Read the Measurement 000 0 eee eee eseeseceseeseceeseeseseeenenaes 2 18 Step 9 Process the Data 0 0 eee
44. EEE 488 2 compatible you can just send it the trigger command TRG The VAL1 command instructs the meter to send the next triggered reading to its output buffer Send 0 fluke TRG VAL1 11L NLend if ibsta amp ERR gpiberr Send trigger error Step 7 Wait for the Measurement After the meter is triggered it takes a measurement and displays it on its front panel and then asserts SRQ You can detect the assertion of SRQ using either the Test SRO or Wait SRO routine If you have a process that you want to execute while you are waiting for the measurement use Test SRQ For this example you can use the Wait SRO routine The first argument in Wait SRQ is the GPIB board number The second argument is a flag returned by Wait SRQ that indicates whether or not SRQ is asserted WaitSRQ 0 amp SRQasserted if SRQasserted gpiberr WaitSRQ error National Instruments Corporation 2 17 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application After you have detected SRQ use the ReadStatusByte routine to poll the meter and determine its status The first argument is the GPIB board number the second argument is the GPIB address of the instrument and the last argument is a variable that ReadStatusByte uses to store the status byte of the instrument ReadStatusByte 0 fluke amp statusByte if ibsta amp ERR gpiberr ReadStatusByte error After you have obtained the status b
45. I O is canceled the driver and application are resynchronized e iboni The I O is canceled and the interface is reset the driver and application are resynchronized B 6 National Instruments Corporation ECAP 11 Appendix B Error Codes and Solutions Solutions EFSO 12 Solutions EBUS 14 ECAP results when your GPIB board lacks the ability to carry out an operation or when a particular capability has been disabled in the software and a call is made that requires the capability Check the validity of the call or make sure your GPIB interface board and the driver both have the needed capability EFSO results when an ibrdf or ibwrtf call encounters a problem performing a file operation Specifically this error indicates that the function is unable to open create seek write or close the file being accessed The specific system error code for this condition is contained in ibent Following are some possible solutions e Make sure the file is in the same folder as your application e Make sure there is enough room on the disk to hold the file Solutions EBUS results when certain GPIB bus errors occur during device functions All device functions send command bytes to perform addressing and other bus management Devices are expected to accept these command bytes within the time limit specified by the default configuration or the ibtmo function EBUS results if a timeout occurred while sending these command
46. Interface Bus Interactive Control Utility 10 Use the read command to display the data on the screen both in hex values and their ASCII equivalents ud0 ibrd enter byte count 18 0100 cmp1 count 18 4e 44 43 56 20 30 30 30 NDCV 000 2e 30 30 34 37 45 2b 30 0047E 0 Oa Oa or ud0 ibrd 18 0100 cmpl count 18 4e 44 43 56 20 30 30 30 NDCV 000 2e 30 30 34 37 45 2b 30 0047E 0 Oa Oa Place the device offline as follows ud0 ibonl enter value 0 0100 cmp1 or ud0 ibonl 0 0100 cmp1 Terminate the IBIC 488 2 program by entering q at the prompt or choosing Quit from the File menu IBIC 488 2 Syntax When you enter commands in IBIC 488 2 you can either include the parameters or the program prompts you for values Some commands require numbers as input values Others might require you to input a string NI 488 2 User Manual for MacOS 4 4 National Instruments Corporation Number Syntax String Syntax Address Syntax Chapter 4 Interface Bus Interactive Control Utility You can enter numbers as hexadecimal octal or decimal integer Hexadecimal numbers Y ou must precede hex numbers by zero and x for example OxD Octal numbers Y ou must precede octal numbers by zero only for example 015 Decimal numbers Enter the number only You can enter strings as an ASCII character sequence octal bytes hex bytes or special symbols ASCII character sequence Y ou must enclose t
47. OK is set the EnableLocal routine or ibloc function is inoperative for that board LOK is set whenever the GPIB board detects that the Local Lockout LLO message has been sent either by the GPIB board or by another Controller LOK is cleared when the System Controller unasserts the Remote Enable REN GPIB line REM indicates whether or not the board is in the remote state REM is set whenever the Remote Enable REN GPIB line is asserted and the GPIB board detects that its listen address has been sent either by the GPIB board or by another Controller REM is cleared in the following situations When REN becomes unasserted e When the GPIB board as a Listener detects that the Go to Local GTL command has been sent either by the GPIB board or by another Controller e When the ibloc function is called while the LOK bit is cleared in the status word CIC brd ATN brd CIC indicates whether the GPIB board is the Controller In Charge CIC is set when the SendIFC routine or ibsic function is executed either while the GPIB board is System Controller or when another Controller passes control to the GPIB board CIC is cleared either when the GPIB board detects Interface Clear IFC from the System Controller or when the GPIB board passes control to another device NI 488 2 User Manual for MacOS ATN indicates the state of the GPIB Attention ATN line ATN is set whenever the GPIB ATN line is asserted and it is cleared when th
48. S 2 4 brd Listener DTAS 1 2 brd Device Trigger State DCAS 0 1 brd Device Clear State The language header files included on your distribution disk contain the mnemonic constants for ibsta You can check a bit position in ibsta by using its numeric value or its mnemonic constant For example bit position 15 hex 8000 detects a GPIB error The mnemonic for this bit is ERR To check for a GPIB error use either of the following statements after each NI 488 function and NI 488 2 routine if ibsta amp ERR gpiberr or if ibsta amp 0x8000 gpiberr where gpiberr is an error handling routine NI 488 2 User Manual for MacOS 2 4 National Instruments Corporation Chapter 2 Developing Your Application Error Variable iberr If the ERR bit is set in the status word ibsta a GPIB error has occurred When an error occurs the error type is specified by the value in iberr Note The value in iberr is meaningful as an error type only when the ERR bit is set indicating that an error has occurred For more information on error codes and solutions refer to Chapter 3 Debugging Your Application or Appendix B Error Codes and Solutions Count Variables ibent and ibentl The count variables are updated after each read write or command function ibcnt and ibcnt1 are both 32 bit integers If you are reading data the count variables indicate the number of bytes read If you are sending data or commands
49. a board number for example n 0 for gpib0 The 488 2 prompt indicates that you are in NI 488 2 mode on board n The following example shows how to enter into 488 2 mode on board gpibo set 488 2 0 488 2 0 Send and SendList The Send routine sends data to a single GPIB device You can use the SendList command to send data to multiple GPIB devices For example suppose you want to send the five character string IDN followed by the new line character with EOI You want to send the message from the computer to the devices at primary address 2 and 17 To do this enter the SendList command at the 488 2 0 promptas shown in the following example 488 2 0 SendList 2 17 IDN NLend 0128 cmpl cic tacs count 6 The returned status word contains the cmp1 bit which indicates a successful I O completion The byte count 6 indicates that six characters including the added new line were sent from the computer and received by both devices National Instruments Corporation 4 15 NI 488 2 User Manual for MacOS Chapter 4 Interface Bus Interactive Control Utility Receive The Receive routine causes the GPIB board to receive data from another GPIB device The following example acquires 10 data bytes from the device at primary address 5 It stops receiving data when 10 characters have been received or when the END message is received The acquired data is then displayed in hex format along with its ASCII equivalent The IBIC
50. abling 5 2 to 5 3 system configuration effects 5 3 terminating 5 1 to 5 2 DAV data valid line 1 3 DCAS status word condition description A 5 waiting for messages from Controller 5 5 debugging applications See also IBIC 488 2 common questions 3 4 to 3 6 communication errors repeat addressing 3 4 termination method 3 4 configuration errors 3 3 global status variables 3 1 NI 488 2 User Manual for MacOS l 2 GPIB error codes 3 2 to 3 3 IBIC 488 2 3 1 to 3 2 NI 488 2 Test 3 1 timing errors 3 3 to 3 4 default configuration for NI 488 2 software 6 3 device frame NI 488 Config utility See bus device frame NI 488 Config utility device level calls and bus management 5 4 DMA option NI 488 Config utility 6 10 documentation conventions used xiii organization of xii related documentation xiii to xiv driver and driver utilities NI 488 2 1 7 DTAS status word condition description A 5 waiting for messages from Controller 5 5 E EABO error code B 5 EADR error code B 4 EARG error code B 4 EBUS error code B 7 ECAP error code B 7 ECIC error code B 2 to B 3 EDMA error code B 6 EDVR error code B 2 EFSO error code B 7 ELCK error code B 9 END status word condition A 2 to A 3 ENEB error code B 5 to B 6 ENOL error code B 3 EOI end or identify line definition table 1 4 termination of data transfers 5 1 to 5 2 EOIP error code B 6 National Instruments Corporation EOS configuring ibeos f
51. al Instruments or to comment on our products and manuals The Glossary contains an alphabetical list and description of terms used in this manual including abbreviations acronyms metric prefixes mnemonics and symbols The Index contains an alphabetical list of key terms and topics in this manual including the page where you can find each one xii National Instruments Corporation About This Manual Conventions Used in This Manual bold italic bold italic monospace bold monospace italic monospace lt gt IEEE 488 and IEEE 488 2 Macintosh The following conventions are used in this manual Bold text denotes commands menus menu items options and screen button names and checkboxes Italic text denotes emphasis cross references field names or an introduction to a key concept Bold italic text denotes a note caution or warning Text in this font denotes text or characters that you enter from the keyboard Sections of code programming examples and syntax examples also appear in this font This font is also used for the proper name of disk drives paths directories device names variables and for statements taken from program code Bold text in this font denotes the messages and responses that the computer automatically prints to the screen Italic text in this font denotes that you must supply the appropriate words or values in the place of these items Angle brackets enclose the name
52. ate drivers for installed National Instruments GPIB interfaces The NI 488 INIT is loaded into memory when the Macintosh is booted NI 488 Config is a configuration utility that you can use to examine or change the software settings NI 488 2 Test is a software diagnostic utility IBIC 488 2 is an interactive control program that you use to communicate with the GPIB devices interactively using NI 488 2 functions and routines It helps you to learn the NI 488 2 routines and to program your instrument or other GPIB devices NI DMA DSP is a system extension that provides DMA functionality through an RTSI connection to an NB DMA2800 or NB DMA 8 The Ethernet folder contains utilities that are applicable if you have a National Instruments GPIB ENET MacGPIB shlbisa shared library that programmers can use to call NI 488 2 routines 1 7 NI 488 2 User Manual for MacOS Chapter 1 Introduction C Language Files IBDIAG NUBUS IBDIAG PCI and IBDIAG PCMCIA are hardware diagnostic utilities PCI_GPIB is a native PowerMac device driver which supports the PCI GPIB interface PCCARD_GPIB is a native PowerMac device driver for PowerBooks that adhere to PC Card 3 0 The C LI Folder contains the following files relevant to programming in THINK C MPW C and Metrowerks CodeWarrior C decl h is a file containing useful variable and constant declarations Devsamp c is a device level sample program Samp4882 c is asample program using NI
53. aterials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this manual is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOS
54. ation B 1 NI 488 2 User Manual for MacOS Appendix B Error Codes and Solutions Table B 1 GPIB Error Codes Continued Error iberr Mnemonic Value Meaning ETAB 20 Table problem ELCK 21 Board or device is locked EDVR 0 EDVR is returned for the following reasons Solutions When the board or device name passed to ibfind is not configured in the software When an invalid unit descriptor is passed to any function call When the driver is not installed In this case ibcnt contains a system level error code Following are some possible solutions ECIC 1 Use ibdev to open a device without specifying its symbolic name Use only device or board names that are configured in the utility program NI 488 Config as parameters in the ibfind function Use the unit descriptor returned from the ibfind function as the first parameter in subsequent NI 488 functions Examine the variable after the ibfind and before the failing function to make sure it was not corrupted Make sure the NI 488 2 driver is installed by checking to see if NI 488 INIT isin the Extensions folder in the System Folder ECIC is returned when one of the following board functions or routines is called while the board is not CIC NI 488 2 User Manual for MacOS Any device level NI 488 functions that affect the GPIB Any board level NI 488 functions that issue GPIB command bytes such as ibcmd ibemda ibln ibrpp ibcac ibgts
55. ce Manual for MacOS Termination of Data Transfers GPIB data transfers are terminated either when the GPIB EOI line is asserted with the last byte of a transfer or when a preconfigured end of string EOS character is transmitted By default the NI 488 2 driver asserts EOI with the last byte of writes and the EOS modes are disabled You can use the ibeot function to enable or disable the end of transmission EOT mode If EOT mode is enabled the NI 488 2 driver asserts the GPIB EOI line when the last byte of a write is sent out on the GPIB If it is disabled the EOI line is not asserted with the last byte of a write You can use the ibeos function to enable disable or configure the EOS modes EOS mode configuration includes the following information e AnEOS byte e EOS comparison method This indicates whether the EOS byte has seven or eight significant bits For a 7 bit EOS byte the eighth bit of the EOS byte is ignored e EOS write method lIf this is enabled the NI 488 2 driver automatically asserts the GPIB EOI line when the EOS byte is written to the GPIB For example if the buffer passed into an ibwrt call contains five occurrences of the EOS byte the EOI line is asserted as each of the five EOS bytes are written to the GPIB If the ibwrt buffer does not contain an occurrence of the EOS byte the EOI line is not asserted unless the EOT mode is enabled in which case the EOI line is asserted with the last byte of the
56. ce resets its internal functions to a default state ibclr ud if ibsta amp ERR gpiberr ibclr error NI 488 2 User Manual for MacOS 2 8 National Instruments Corporation Chapter 2 Developing Your Application Step 3 Configure the Device After you open and clear the device it is ready to receive commands To configure the instrument you send device specific commands using the ibwrt function Refer to the instrument user manual for the command bytes that work with your instrument ibwrt ud RST VAC AUTO TRIGGER 2 SRE 16 35L if ibsta amp ERR gpiberr ibwrt error The programming instruction in this example resets the multimeter RST The meter is instructed to measure the volts alternating current VAC using auto ranging AUTO to wait for a trigger from the GPIB interface board before starting a measurement TRIGGER 2 and to assert the SRQ line when the measurement completes and the multimeter is ready to send the result SRE 16 Step 4 Trigger the Device If you configure the device to wait for a trigger you must send a trigger command to the device before reading the measurement value Then instruct the device to send the next triggered reading to its GPIB output buffer ibtrg ud if ibsta amp ERR gpiberr ibtrg error ibwrt ud VAL1 5L if ibsta amp ERR gpiberr ibwrt error National Instruments Corporation
57. ceceseeeseeseees xii Conventions Used in This Manual sssisirsiriiirsiieireiirsrisireiieiesireirieidediieriesisisesriiide iseis xiii Related Documentation ennie a E EE EE AAEE Ea xiii Customer COMMUNICATION nn seeria E E Ea E EE E E EEN xiv Chapter 1 Introduction GPIB Ove EW a E E R E e A T E ae N 1 1 Talkers Listeners and Controllers cccccccccccesssceceeceesscececeeessneceeeeesersseeecees 1 1 Controller In Charge and System Controller cece eeeeseeseeeeeeseeseeeseenseeaes 1 2 GPIB A dre ssin 8 onee e S E RE E E E RE 1 2 Sending Messages Across the GPIB eseseesssseresssreersresrsreeerisseeresreresreeesreee 1 3 Data LANES vesn eraren t e a are a aa aa e aia ni 1 3 Handshake Lines niin S EE EEA E 1 3 Interface Management Lines eesseseesseseseseesesesrereresesreseseeserseeseesee 1 4 Setting Up and Configuring Your System eee cece eeeeeeeeeeeeeeeneeeeeaes 1 4 Controlling More Than One Board eee eeeeeeeeeeeereeeeeseeseeaes 1 5 Configuration Requirements 0 0 0 0 ee eceeeeseeeeeeeeseecsecseeaecsaeeseceeeeeeeeeeseseeseaes 1 6 NI 488 2 Software Components eieiei tessens auburn stern EES E 1 7 NI 488 2 Driver and Driver Utilities 0 00 ceseeeeceseeeeceeeeeeeeeeeeeseneeaee 1 7 GC Tan euage E ENA E A AAP E TE EEEE E EEEE EEE ETE 1 8 FutureBASIC Language Files seessseesesseseseeseeeesreersreerereeerrsreeresreresrenrsreneers 1 8 How the NI 488 2 Software Works with Your System eee esses eeeeeee 1 9 Chapter 2 Develo
58. ceeeeceseeeeceeecseeseecseesecnsceeeeeseneeaee 2 19 Step 10 Place the Board Offline 0 ce cesses ceeeeeeeeeeesesseeeeeaes 2 19 Compiling Linking and Running 00 eee ce eeeeseeeeecseeeceseeseeeeseeeeseeeseeaes 2 19 C Applications ss sessce sessca scvcacsssens ou iesseediginta sivas Lede iSS eo Eora Kirsi 2 19 FutureBASIC Applications cece ceceeeecesececessecseeeceseeeeseeeseeaes 2 20 NI 488 2 User Manual for MacOS vi National Instruments Corporation Chapter 3 Debugging Your Application Running NI 48822 Testenine arster reor or a E ave ans EERTE TE E a 3 1 Debugging with the Global Status Variables elec ceseeteceeceneeeeeeeeees 3 1 Debugging with IBIC488 2 iisirireiesmoesessisiiseescssisir iospiras reiese iiir pepin 3 1 GPIB Error Codes EEE Sekai SAE A T 3 2 Configuration Errors escosesa oa E aa e EE EEEE E rE Ei 3 3 Timing Errors soene Sea aon ik wins Aen Oa wah aA 3 3 Communication Errors c cccccsccecessecessececesecesecceesssecesesaeecseeeeeeseecseseeeseeeeenenes 3 4 Repeat Addressing sieren eni eenei Son sacwacnaseunees E EEr EESE EENES 3 4 Termination Method ccccseccesssseeessseceesseecseneeeceseeeeesececesaeceseneeeees 3 4 Common Questions e e ee atest BA es 3 4 Chapter 4 Interface Bus Interactive Control Utility OVELVIEW 25 0 oe8 Sais nae a SA he ae Be ae 4 1 Example Using NI 488 Functions 000 eeceeeeeeeceeeesecaeecaecesesaeceeeseceeeeseeeeeeseseneeas 4 1 IBIC 488 2 Syntax eeni eee Re EEE
59. cific commands are sent across the GPIB to change their state You might need to configure your NI 488 2 driver to perform repeat addressing if your device does not remain in its currently addressed state Refer to Chapter 6 GPIB Configuration Utility or to the description of ibconfig option IbcREADDR in the NI 488 2 Function Reference Manual for MacOS for more information about reconfiguring your software Termination Method You should be aware of the data termination method that your device uses By default your NI 488 2 software is configured to send EOI on writes and terminate reads on EOI or a specific byte count If you send a command string to your device and it does not respond it might be because it does not recognize the end of the command You might need to send a termination message such as lt CR gt lt LF gt after a write command as follows ibwrt dev COMMAND x0A x0D 9 Common Questions What do I do if NI 488 2 Test fails with an error Refer to the getting started manual for specific information about what might cause this test to fail NI 488 2 User Manual for MacOS 3 4 National Instruments Corporation Chapter 3 Debugging Your Application How do I communicate with my instrument over the GPIB Refer to the documentation that came from the instrument manufacturer The command sequences you use are totally dependent on the specific instrument The documentation for each instrument should inc
60. ck access to the connection National Instruments Corporation B 9 NI 488 2 User Manual for MacOS Appendix Customer Communication For your convenience this appendix contains forms to help you gather the information necessary to help us solve your technical problems and a form you can use to comment on the product documentation When you contact us we need the information on the Technical Support Form and the configuration form if your manual contains one about your system configuration to answer your questions as quickly as possible National Instruments has technical assistance through electronic fax and telephone systems to quickly provide the information you need Our electronic services include a bulletin board service an FTP site a fax on demand system and e mail support If you have a hardware or software problem first try the electronic support systems If the information available on these systems does not answer your questions we offer fax and telephone support through our technical support centers which are staffed by applications engineers Electronic Services Bulletin Board Support National Instruments has BBS and FTP sites dedicated for 24 hour support with a collection of files and documents to answer most common customer questions From these sites you can also download the latest instrument drivers updates and example programs For recorded instructions on how to use the bulletin board and FTP service
61. complete These forms are in Appendix C Customer Communication at the end of this manual xiv National Instruments Corporation Chapter Introduction This chapter gives an overview of GPIB and the NI 488 2 software GPIB Overview The ANSI IEEE Standard 488 1 1987 also known as GPIB General Purpose Interface Bus describes a standard interface for communication between instruments and controllers from various vendors It contains information about electrical mechanical and functional specifications The GPIB is a digital 8 bit parallel communications interface with data transfer rates of 1 MB s and above The bus supports one System Controller usually a computer and up to 14 additional instruments The ANSI IEEE Standard 488 2 1987 extends IEEE 488 1 by defining a bus communication protocol a common set of data codes and formats and a generic set of common device commands Talkers Listeners and Controllers GPIB devices can be Talkers Listeners or Controllers A Talker sends out data messages Listeners receive data messages The Controller usually a computer manages the flow of information on the bus It defines the communication links and sends GPIB commands to devices Some devices are capable of playing more than one role A digital voltmeter for example can be a Talker and a Listener If your personal computer has a National Instruments GPIB interface board and the NI 488 2 software installed it
62. d description of the conditions reported in the status word ibsta For information about how to use ibsta in your application program refer to Chapter 2 Developing Your Application If a function call returns an ENEB or EDVR error all status word bits except the ERR bit are cleared indicating that it is not possible to obtain the status of the GPIB board Each bit in ibsta can be set for device calls dev board calls brd or both dev brd Table A 1 lists the status word bits Table A 1 Status Word Bits Bit Hex Mnemonic Pos Value Type Description ERR 15 8000 dev brd GPIB error TIMO 14 4000 dev brd Time limit exceeded END 13 2000 dev brd END or EOS detected SRQI 12 1000 brd SRQ interrupt received RQS 11 800 dev Device requesting service CMPL 8 100 dev brd I O completed LOK 7 80 brd Lockout State REM 6 40 brd Remote State CIC 5 20 brd Controller In Charge National Instruments Corporation A 1 NI 488 2 User Manual for MacOS Appendix A Status Word Conditions Table A 1 Status Word Bits Continued Bit Hex Mnemonic Pos Value Type Description ATN 4 10 brd Attention is asserted TACS 3 8 brd Talker LACS 2 4 brd Listener DTAS 1 2 brd Device Trigger State DCAS 0 1 brd Device Clear State ERR dev brd ERR is set in the status word following any call that results in an error You can determine the particular erro
63. device If you configure any bus or device for secondary addressing all buses and devices used by the application must be configured for secondary addressing NI 488 2 User Manual for MacOS 6 8 National Instruments Corporation Chapter 6 GPIB Configuration Utility Repeat Addressing Normally a device remains addressed after a read or write operation is performed However some devices require addressing for each operation If you check the Repeat Addressing box read or write operations readdress the selected device even if the same operation was just performed with that device Timeout The timeout value is the approximate length of time that can elapse before I O functions complete Select the I O timeout of the bus or device from the Timeout pop up menu The abbreviations used in the Timeout pop up menu are usec microseconds msec milliseconds and sec seconds Selecting None means I O for this bus or device will never time out EOS Modes The following options determine how the device I O transmissions terminate e Read END on EOS Some devices send an EOS byte signaling the last byte of a data message Checking this box causes the NI 488 2 software to terminate read operations when it receives the EOS byte e Write END on EOS Checking this box causes the NI 488 2 software to assert the EOI send End line when the EOS character is sent e Write END on Last Byte Some devices as Listeners require that the Ta
64. dle char SerialPollResponse 0 ibwait DeviceHandle TIMO RQS if ibsta amp ROS printf Device asserted SRQ n Use ibrsp to retrieve the serial poll response ibrsp DeviceHandle amp SerialPollResponse j return SerialPollResponse NI 488 2 User Manual for MacOS 5 8 National Instruments Corporation Chapter 5 GPIB Programming Techniques SRQ and Serial Polling with NI 488 2 Routines The NI 488 2 software includes a set of NI 488 2 routines that you can use to conduct SRQ servicing and serial polling Routines pertinent to SRQ servicing and serial polling are A11Spo11 FindRQS ReadStatusByte TestSROQ and WaitSRQ All1Spol11 can serial poll multiple devices with a single call It places the status bytes from each polled instrument into a predefined array Then you must check the RQS bit of each status byte to determine whether that device requested service ReadStatusByte is similar to Al1Spo11 except that it serial polls only a single device It is also analogous to the device level NI 488 ibrsp function FindROQs serial polls a list of devices until it finds a device that is requesting service or until it has polled all of the specified devices The routine returns the index and status byte value of the device requesting service TestSRQ determines whether the SRQ line is asserted or unasserted and returns to the program immediately WaitSRQ is similar to Test SROQ
65. dware 5 2 National Instruments Corporation U Unaddressing option NI 488 Config utility 6 11 Use Bus option NI 488 Config utility 6 12 W WaitSRQ routine 5 9 writing applications See programming National Instruments Corporation Index NI 488 2 User Manual for MacOS
66. e Read data to file where f1name is pathname of file to read ibrpp Conduct a parallel poll ibrsp Return serial poll byte ibsad v Change secondary address ibstop Abort asynchronous operation ibtmo v Change disable time limit ibtrg Trigger selected device ibwait mask Wait for selected event where mask is a hex octal or decimal integer or a mask bit mnemonic ibwrt string Write data ibwrta string ibwrtf flname Write data asynchronously Write data from a file where f1name is pathname of file to write Table 4 2 Syntax for Device Level NI 488 Functions in IBIC 488 2 Syntax Description ibcac v Become Active Controller ibcmd string Send commands ibcmda string Send commands asynchronously ibconfig mn v Alter configurable parameters where mn is mnemonic for a configuration parameter or equivalent integer value ibdma v Enable disable DMA ibeos v Change disable EOS message ibeot v Enable disable END message National Instruments Corporation 4 7 NI 488 2 User Manual for MacOS Interface Bus Interactive Control Utility Table 4 2 Syntax for Device Level NI 488 Functions in IBIC 488 2 Continued Syntax Description ibfind udname Return unit descriptor where udname is the symbolic name of a board for example gpib0 ibgts v Go from Active Controller to standby ibist v Set clear ist iblines Read the s
67. e ATN line is unasserted A 4 National Instruments Corporation TACS brd Appendix A Status Word Conditions LACS brd TACS indicates whether the GPIB board is addressed as a Talker TACS is set whenever the GPIB board detects that its talk address and secondary address if enabled has been sent either by the GPIB board itself or by another Controller TACS is cleared whenever the GPIB board detects the Untalk UNT command its own listen address a talk address other than its own talk address or Interface Clear IFC DTAS brd LACS indicates whether the GPIB board is addressed as a Listener LACS is set whenever the GPIB board detects that its listen address and secondary address if enabled has been sent either by the GPIB board itself or by another Controller LACS is also set whenever the GPIB board shadow handshakes as a result of the ibgts function LACS is cleared whenever the GPIB board detects the Unlisten UNL command its own talk address Interface Clear IFC or that the ibgts function has been called without shadow handshake DCAS brd DTAS indicates whether the GPIB board has detected a device trigger command DTAS is set whenever the GPIB board as a Listener detects that the Group Execute Trigger GET command has been sent by another Controller DTAS is cleared on any call immediately following an ibwait call if the DTAS bit is set in the ibwait mask parameter DCAS indicates whether
68. e A maximun total cable length of 20 m e A maximum of 15 devices connected to each bus with at least two thirds powered on For high speed operation the following restrictions apply e All devices in the system must be powered on e Cable lengths should be as short as possible up to a maximum of 15 m of cable in each system e There must be at least one equivalent device load per meter of cable NI 488 2 User Manual for MacOS 1 6 National Instruments Corporation Chapter 1 Introduction If you want to exceed these limitations you can use bus extenders to increase the cable length or expanders to increase the number of device loads Extenders and expanders are available from National Instruments The following sections describe the NI 488 2 software which controls the flow of communication on the GPIB NI 488 2 Software Components The following section highlights important elements of the NI 488 2 software for MacOS and describes the function of each element NI 488 2 Driver and Driver Utilities The NI 488 2 software includes the following driver and utility files National Instruments Corporation Read Me is a documentation file that contains important information about the NI 488 2 software and a description of any new features Before you use the software read this file for the most recent information NI 488 2 Installer is an application that installs the NI 488 2 software NI 488 INIT loads the appropri
69. e new name of the device that you entered appears in the Bus Device pop up menu However to avoid the confusion of naming and renaming devices use the NI 488 function ibdev in new applications to dynamically configure new devices You can use ibdev to configure the driver from your program instead of from the configuration utility National Instruments Corporation 6 11 NI 488 2 User Manual for MacOS Chapter 6 GPIB Configuration Utility Use Bus You can connect the device displayed on the Bus Device pop up menu to a different bus by selecting the new bus from the Use Bus pop up menu The new bus number appears to the left of the device name in the Bus Device pop up menu Exiting the Configuration Utility To exit the configuration utility click on the close box in the upper left corner of the configuration screen An alert message displays if you close the utility while any of the following conditions applies e The Macintosh must be restarted to load new drivers or change the serial port PCI buffers or ENET connection settings e A device GPIB address conflicts with the GPIB address of the bus to which it is connected Each GPIB address must be unique e No GPIB board is in the slot associated with one of the buses e A bus or device I O timeout is set to None disabled NI 488 2 User Manual for MacOS 6 12 National Instruments Corporation Status Word Conditions Appendix This appendix gives a detaile
70. e transmitted to the device This indicates that either dev1 is powered off or the GPIB cable is disconnected For a detailed list of the error codes and their meanings refer to Chapter 3 Debugging Your Application National Instruments Corporation 4 11 NI 488 2 User Manual for MacOS Chapter 4 Count Interface Bus Interactive Control Utility When an I O function completes IBIC 488 2 displays the actual number of bytes sent or received regardless of the existence of an error condition If one of the addresses in an address list of an NI 488 2 routine is invalid then the error is EARG and IBIC 488 2 displays the index of the invalid address as the count The count has a different meaning depending on which NI 488 function or NI 488 2 routine is called Refer to the function descriptions in the NI 488 2 Function Reference Manual for MacOS for the correct interpretation of the count return Common NI 488 Functions ibdev Following are some common NI 488 functions The ibdev command initializes a device descriptor with the input information With ibdev you specify the following values e Access board for the device e Primary address e Secondary address e Timeout setting e EOT mode e EOS mode The following example shows ibdev opening an available device and assigning it to access gpib0 board 0 with a primary address of 6 pad 6 a secondary address of hex 67 sad 0x67 a timeout of 10 s tmo 1
71. ed the SRQ line and responds accordingly The most common method for SRQ detection and servicing is the serial poll National Instruments Corporation 5 5 NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques Service Requests from IEEE 488 Devices IEEE 488 devices request service from the GPIB Controller by asserting the GPIB SRQ line When the Controller acknowledges the SRQ it serial polls each open device on the bus to determine which device requested service Any device requesting service returns a status byte with bit 6 set and then unasserts the SRQ line Devices not requesting service return a status byte with bit 6 cleared Manufacturers of IEEE 488 devices use lower order bits to communicate the reason for the service request or to summarize the state of the device Service Requests from IEEE 488 2 Devices The IEEE 488 2 standard refined the bit assignments in the status byte In addition to setting bit 6 when requesting service IEEE 488 2 devices also use two other bits to specify their status Bit 4 the Message Available bit MAV is set when the device is ready to send previously queried data Bit 5 the Event Status bit ESB is set if one or more of the enabled IEEE 488 2 events occurs These events include power on user request command error execution error device dependent error query error request control and operation complete The device can assert SRQ when ESB or MAV are set or when a manufac
72. ede enen eaea oaa A tededdesheveteaveeneetteets 6 3 Control tems 5 eet ne a et AS Re ee ee 6 4 Help Fraen a E stave giebueeeiaue herent eees 6 4 Global Frames sient ote r ete hes Go et RE ee 6 5 NI 488 2 User Manual for MacOS viii National Instruments Corporation Buis De vice Frames earann ose eeose epe ae So e A EEE E le an ene EET cess 6 6 Options for Buses or Devices e sesseeesseesesresesrererersreerereererresreresere 6 8 Primary Address noseci ienis uel sh beee e a benny 6 8 Secondary Address siioni eree esei 6 8 Repeat Addressing eesseeesseeeseereesssreresrsrrrrerrsrrsererererrssese 6 9 BETIO EEEE E T 6 9 FOS ModE r r a eee ea ESEE VEEE EE NE iste 6 9 BOS Byler a a E T ENA 6 9 Options for Buses Only ese cesses ceseeseceeceseeseeeeeeeseaeeeeeeneeeaes 6 10 Bus TIMIN Tk iee speci accents esaerea taoa ora EEE a ES ois 6 10 TNT High Speed seein ee eeoa TEE 6 10 DMA a a E R A ae 6 10 System Controller s issssneirsnieo nrs erri ienee esei 6 11 Assert REN when System Controller s eessessesseereeeeeeeeee 6 11 Un ddressin g ceci esise ere Ea a dae E E 6 11 Options for Devices Only ssessseesesssseserereessreerereerrsrsserreseeresresrsrrereees 6 11 Rename Devices eciccescsteicec ces ateviasnen sunseiaebaehe AE RER ea 6 11 Use BUS errare reses eetere aap iee a Ea E ao ESETE 6 12 Exiting the Configuration Utility esessseeeeeeeeeseeesersresrsstrrsseeresrererrssenreseersreserresreereeeet 6 12 Appendi
73. enceceeecaeeeeeeetreseneeeenees 4 17 Repeat Previous FUnction ceeessecescecsseeesseeeececeeceeseceeecaeceaeeceeeecneeeeneees 4 18 n Repeat Function n Times erriei E E EE ETE 4 18 Execute Indirect File s czcc c see scgsSshes cnn iatond oh Gain ope dvd vee he oes helena 4 18 Buffer Set Buffer Display Mode cece cee ceeeesecseceseesseeseeseceeeeeeseneeeeseneeaee 4 19 National Instruments Corporation vii NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques Termination of Data Transters s c secsscuecsscesveescseesssvtscs oaseccess abe sbevasdupeiste sss qposedebebensseeeses 5 1 High Speed Data Transfers HS488 oo eee cseee cee ceseeeceeceeeeeeeeeseaeeeaeeaee 5 2 Enabling HS488 3 2 sss sisc s5tes santas sec sbesens cs sctesaesgesseevesoss ds vae seonssadesiseescevess 5 2 System Configuration Effects on HS488 00 eseseceecereeees 5 3 Waiting for GPIB Conditions 0 eee ceseeseceeceseeeeeeeeeeeeeseeeneeaee 5 4 Device Level Calls and Bus Management eee eseececeeeeeeeeeeeeeeeneeeneeaee 5 4 Talker Listener Applications 1ssccscssscssccsessissseesssssstssepssedneses ogbedcesscssenssdesstesnsoaessoevesbes 5 5 Waiting for Messages from the Controller eee eeeeceeeeseeeeeeeseeeeseeeseenee 5 5 Requesting SCrviCe cesccssscusciviscieesscehsgues socstevencnseebes ep E er EEr E TEE aaa 5 5 Seral PolINE ee ee SR EE a ENE AEE EE AES O EES 5 5 Service Requests from IEEE 488 Devices seseeesseeesserese
74. er and Controller functions in hardware Transistor transistor logic A variable name and first argument of each function call that contains the unit descriptor of the GPIB interface board or other GPIB device that is the object of the function Unlisten is the GPIB command used to unaddress any active Listeners Untalk is the GPIB command used to unaddress an active Talker G 8 National Instruments Corporation Numbers Symbols Repeat Previous Function IBIC 488 2 4 18 Execute Indirect File function IBIC 488 2 4 18 A address syntax IBIC 488 2 4 5 addressing GPIB address bits illustration 1 2 configuring in NI 488 Config utility Primary Address option 6 8 Repeat Addressing option 6 9 Secondary Address option 6 8 Unaddressing option 6 11 overview 1 2 repeat addressing 3 4 AllSpoll routine 5 9 5 11 ANSI TEEE Standard 488 1 1987 1 1 application development See debugging applications programming Assert REN When System Controller option NI 488 Config utility 6 11 ATN attention line 1 4 ATN status word condition A 4 automatic serial polling See serial polling auxiliary functions IBIC 488 2 Repeat Previous Function 4 18 Execute Indirect File 4 18 Buffer Set Buffer Display Mode 4 19 Help Display Help Information 4 17 list of functions table 4 16 to 4 17 National Instruments Corporation Index n Repeat Function n Times 4 18 Set Select Device or
75. er than three HS488 devices connected by four meters of cable National Instruments Corporation 5 3 NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques Waiting for GPIB Conditions You can use the ibwait function to obtain the current ibsta value or to suspend your application until a specified condition occurs on the GPIB If you use ibwait with a parameter of zero it immediately updates ibsta and returns If you want to use ibwait to wait for one or more events to occur then pass a wait mask to the function The wait mask should always include the TIMO event otherwise your application is suspended indefinitely until one of the wait mask events occurs Device Level Calls and Bus Management The NI 488 device level calls are designed to perform all of the GPIB management for your application program However the NI 488 2 driver can handle bus management only when the GPIB interface board is CIC Controller In Charge Only the CIC is able to send command bytes to the devices on the bus to perform device addressing or other bus management activities Use one of the following methods to make your GPIB board the CIC e If your GPIB board is configured as the System Controller default it automatically makes itself the CIC by asserting the IFC line the first time you make a device level call e If your setup includes more than one Controller or if your GPIB interface board is not configured as the System Controlle
76. evice functions that hide much of the GPIB management operations and low level or board functions that offer you more control over the GPIB than NI 488 2 routines The following sections describe these different function types NI 488 Device Functions Device functions are high level functions that automatically execute commands that handle bus management operations such as reading from and writing to devices or polling them for status If you use device functions you do not need to understand GPIB protocol or bus management For information about device level calls and how they manage the GPIB refer to Device Level Calls and Bus Management in Chapter 5 GPIB Programming Techniques NI 488 Board Functions Board functions are low level functions that perform rudimentary GPIB operations Board functions access the interface board directly and require you to handle the addressing and bus management protocol In cases when the high level device functions might not meet your needs low level board functions give you the flexibility and control to handle situations such as the following e Communicating with non compliant non IEEE 488 2 devices e Altering various low level board configurations e Managing the bus in non typical ways The NI 488 board functions are compatible with and can be interspersed within sequences of NI 488 2 routines When you use board functions within a sequence of NI 488 2 routines you do not need a prior cal
77. figuration messages using ibcmd or SendCmds The HS488 configuration message is made up of two GPIB command bytes The first byte the Configure Enable CFE message hex 1F places all HS488 devices into their configuration mode Non HS488 devices should ignore this message The second byte is a GPIB secondary command that indicates the number of meters of cable in your system It is called the Configure CFGn message Because HS488 can operate only with cable lengths of 1 to 15 meters only CFGn values of 1 through 15 hex 61 through 6F are valid If the cable length was configured correctly in the configuration utility you can determine how many meters of cable are in your system by calling ibask option IbaHSCableLength in your application program For CFE and CFGn messages refer to Appendix A Multiline Interface Messages in the NI 488 2 Function Reference Manual for MacOS System Configuration Effects on HS488 Maximum data transfer rates can be limited by your host computer and GPIB system setup For example even though the theoretical maximum transfer rate with HS488 is 8 MB s the maximum transfer rate obtainable on Macintosh computers with a NuBus is 2 MB s The same IEEE 488 cabling constraints for a 350 ns T1 delay apply to HS488 As you increase the amount of cable in your GPIB configuration the maximum data transfer rate using HS488 decreases For example two HS488 devices connected by two meters of cable can transfer data fast
78. he entire sequence in quotation marks for example tst To include a quotation mark in a string precede it with a backslash for example ab cd Octal bytes You must use a backslash character followed by the octal value For example octal 40 is represented by 40 and can be used ina string as ab 40cd Hex bytes You must use a backslash character and an x followed by the hex value For example hex 40 is represented by x40 and can be used in a string as ab x40cd Special Symbols Some instruments require special termination or end of string EOS characters that indicate to the device that a transmission has ended The two most common EOS characters are r and n r represents a carriage return character and n represents a linefeed character You can use these special characters to insert the carriage return and linefeed characters into a string as in F3R5T1 r n Many of the NI 488 2 routines have an address or address list parameter An address is a 16 bit representation of the GPIB address of a device The primary address is stored in the low byte and the secondary address if any is stored in the high byte For example a device at primary address 6 and secondary address 0x67 has an address of 0x6706 A NULL address is represented as Oxffff National Instruments Corporation 4 5 NI 488 2 User Manual for MacOS Chapter 4 Interface Bus Interactive Control Utility IBIC 488 2 Syntax for NI 488 Functions Table
79. ibcnt DeviceResponse SerialPollResponse return NI 488 2 User Manual for MacOS 5 10 National Instruments Corporation Chapter 5 GPIB Programming Techniques Example 2 Using AllSpoll This example illustrates the use of Al1Spo11 to serial poll three devices void GetAllSerialPollResponses Addr4882_t AddrList short ResponseList int WaitResult WaitSRQ 0 amp WaitResult if WaitResult printf SRO is asserted n Use Allspoll to serial poll all the devices at once AllSpoll 0 AddrList ResponseList if ibsta amp ERR for i 0 AddrList i NOADDR i printf Device at pad x returned byte x n AddrList i ResponseList i return Parallel Polling Although parallel polling is not widely used it is a useful method for obtaining the status of more than one device at the same time The advantage of a parallel poll is that it can easily check up to eight individual devices at once In comparison eight separate serial polls would be required to check eight devices for their serial poll response bytes Implementing a Parallel Poll You can implement parallel polling with either NI 488 functions or NI 488 2 routines If you use NI 488 2 routines to execute parallel National Instruments Corporation 5 11 NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques polls you do not need extensive knowledge of the parallel
80. igure function Kilobytes of memory See MLA Code that enables an application program that uses NI 488 functions or NI 488 2 routines to access the driver See MLA A GPIB device that receives data messages from a Talker See board level function Meters The Message Available bit is part of the IEEE 488 2 defined status byte which is received from a device responding to a serial poll Megabytes of memory Resident in RAM A GPIB command used to address a device to be a Listener It can be any one of the 31 primary addresses NI 488 2 User Manual for MacOS Glossary MSA My Secondary Address is the GPIB command used to address a device My Secondary Address to be a Listener or a Talker when extended two byte addressing is used The complete address is a MLA or MTA address followed by an MSA address There are 31 secondary addresses for a total of 961 distinct listen or talk addresses for devices MTA My Talk Address A GPIB command used to address a device to be a Talker It can be any one of the 31 primary addresses NDAC One of the three GPIB handshake lines See handshake Not Data Accepted NI 488 Config The NI 488 2 driver configuration control panel utility NRFD One of the three GPIB handshake lines See handshake Not Ready For Data P parallel poll The process of polling all configured devices at once and reading a composite poll response See serial poll PIO See programmed I O PPC Paral
81. ility C Auto Configure scan bus gpib gt Interface Type NuBus boards Bus Device i C oma Primary Address Q_ Bd system Secondary Address i Assert REN when System oO Unaddressing C Repeat Addressing C Read END on EOS C Write END on EOS i EJ write END on Last Byte Configuration Sets nell afa O Bit Eos Load set cos eyte 0 Check to associate System slot 3 NuBus slot B with the next free bus Figure 6 4 Manual Bus Association in NI 488 Config Selecting the Auto Configure checkbox in the global frame automatically configures the buses according to the way the boards are contained in the system When Auto Configure is checked each bus gpib0 through gpib7 is associated with the next GPIB board found by the Slot Manager when searching System slots 1 through 6 NuBus slots 9 through E and expansion slots x1 through x8 NuBus slots 1 through 8 Select the Auto Configure checkbox unless your application requires compatibility with older releases of the NI 488 2 driver where the naming conventions of the buses are different Do not check the Auto Configure checkbox if you want to change the order that device identifying software uses GPIB interfaces Items in the bus device frame configure characteristics of a bus a device or either Table 6 1 lists the primary bus device options available in NI 488 Config The sections following the table describe the options in more detail NI 488 2 User Manual for
82. l polls 5 12 unconfiguring device for parallel polling 5 13 ibrd function 4 14 ibrpp function 5 13 ibrsp function 5 7 ibrsrv function 5 5 ibsta See status word ibsta ibwait function conducting serial polls 5 7 Talker Listener applications 5 5 terminating stuck SRQ state 5 7 waiting for GPIB conditions 5 4 ibwrt function 4 14 IFC interface clear line 1 4 Interface Bus Interactive Control utility BIC 488 2 See IBIC 488 2 interface management lines ATN attention 1 4 EOI end or identify 1 4 IFC interface clear 1 4 National Instruments Corporation l 5 Index REN remote enable 1 4 SRQ service request 1 4 interrupts and autopolling 5 7 L LACS status word condition description A 5 waiting for message from Controller 5 5 lines See signals and lines Listeners definition 1 1 Talker Listener applications 5 5 LOK status word condition A 4 Message Available MAV bit 5 6 messages sending across GPIB 1 3 to 1 4 n Repeat Function n Times function IBIC 488 2 4 18 NDAC not data accepted line 1 3 NI 488 applications programming See programming NI 488 Config utility Assert REN When System Controller option 6 11 bus device frame 6 6 to 6 7 bus only options 6 10 to 6 11 bus or device options 6 8 to 6 10 device only options 6 11 to 6 12 options table 6 7 Bus Device menu 6 1 to 6 2 Bus Timing option 6 10 control items 6 4 default configuration 6 3 DMA option
83. l to ibfind to obtain a board descriptor You simply substitute the board index as the first parameter of the board function call With this flexibility you can handle non standard or unusual situations that you cannot resolve using NI 488 2 routines only NI 488 2 User Manual for MacOS 2 2 National Instruments Corporation Chapter 2 Developing Your Application Using NI 488 2 Routines Multiple Boards and or Multiple Devices When your system includes a board that must access more than one device use the NI 488 2 routines NI 488 2 routines can perform the following tasks with a single call e Find all of the Listeners on the bus e Find a device requesting service e Determine the state of the SRQ line or wait for SRQ to be asserted e Address multiple devices to listen Checking Status with Global Variables Each NI 488 function and NI 488 2 routine updates the global variables to reflect the status of the device or board that you are using The status word ibsta the error variable iberr and the count variables ibent and ibcnt1 contain useful information about the performance of your application program Your program should check these variables frequently The following sections describe each of these global variables and how you can use them in your application program You can print out the values of the global variables at any time while the application is running Status Word ibsta All functions update a global stat
84. least one more response byte If this happens you should continue to call ibrsp until RQS is cleared Stuck SRQ State If autopolling is enabled and the GPIB interface board detects an SRQ the driver serial polls all open devices connected to that board The serial poll continues until either SRQ unasserts or all the devices have been polled If no device responds positively to the serial poll or if SRQ remains in effect because of a faulty instrument or cable a stuck SRQ state is in effect If this happens during an ibwait for RQS the driver reports the ESRQ error If the stuck SRQ state happens no further polls are attempted until another ibwait for RQS is made Whenever ibwait is issued the stuck SRQ state is terminated and the driver attempts a new set of serial polls Autopolling and Interrupts If autopolling is enabled the NI 488 2 software can perform autopolling after any device level NI 488 call as long as no GPIB I O is currently in progress This means that an automatic serial poll can occur even when your application is not making any calls to the NI 488 2 software Autopolling can also occur when a device level ibwait for RQS is in progress Autopolling is not allowed whenever an application calls a board level NI 488 function or any NI 488 2 routine or the stuck SRQ ESRQ condition occurs If autopolling is enabled and interrupts are disabled you can use autopolling in the following situations only e During a de
85. lect NI 488 Config The NI 488 Config utility displays the currently defined values for characteristics of a particular device or bus such as addressing and timeout information Help for modifying the current settings is available at the bottom of the window The NI 488 Config configuration utility consists of three frames arranged vertically and separated by a heavy line National Instruments Corporation 6 1 NI 488 2 User Manual for MacOS Chapter 6 GPIB Configuration Utility N1488 Config National Instruments GPIB Configuration Utility x Auto Configure sean bus qb Interface Type NuBus boards Bus Device i J oma Primary Address QB system controtter Secondary Address amp Assert REN when System Timeout go Unaddressing Bus Timing C Repeat Addressing C Read END on EOS C Write END on EOS 4 Write END on Last Byte O ssit Eos EOS Byte Help message box for each dialog item Refer to the User Manual for more information Configuration Sets Figure 6 1 Opening Screen of NI 488 Config The global and bus device frames contain the configuration characteristic settings The help frame displays information about the item over which the cursor is positioned The Interface Type and Bus Device menus affect the display of configuration controls For example selecting a serial interface hides the Auto Configure checkbox NI 488 2 User Manual for MacOS 6 2
86. lel Poll Configure is the GPIB command used to configure an Parallel Poll Configure addressed Listener to participate in polls PPD Parallel Poll Disable is the GPIB command used to disable a configured Parallel Poll Disable device from participating in polls There are 16 PPD commands PPE Parallel Poll Enable is the GPIB command used to enable a configured Parallel Poll Enable device to participate in polls and to assign a DIO response line There are 16 PPE commands PPU Parallel Poll Unconfigure is the GPIB command Parallel Poll used to disable anydevice from participating in Unconfigure polls programmed I O Low speed data transfer between the GPIB board and memory in which the CPU moves each data byte according to program instructions See DMA NI 488 2 User Manual for MacOS G 6 National Instruments Corporation RAM RQS S SC SDC serial poll Service Request source handshake SPD Serial Poll Disable SPE Serial Poll Enable SRQ Service Request startup status byte status word System Controller Glossary Random access memory Request Service See System Controller Selected Device Clear is the GPIB command used to reset internal or device functions of an addressed Listener See DCL and IFC The process of polling and reading the status byte of one device at a time See parallel poll See SRQ The GPIB interface function that transmits data and commands Talkers use this
87. list of addresses separated by commas For more information about the routine parameters use the IBIC 488 2 help feature or refer to the NI 488 2 Function Reference Manual for MacOS Table 4 3 Syntax for NI 488 2 Routines in IBIC 488 2 Routine Syntax Description AllSpoll addrlist Serial poll multiple devices DevClear address Clear a device DevClearList addrlist Clear multiple devices EnableLocal addrlist Enable local control EnableRemote addrlist Enable remote control FindLstn addrlist limit Find all Listeners FindRQS addrlist Find device asserting SRQ PassControl address Pass control to a device PPoll Parallel poll devices National Instruments Corporation 4 9 NI 488 2 User Manual for MacOS Chapter 4 Interface Bus Interactive Control Utility Table 4 3 Syntax for NI 488 2 Routines in IBIC 488 2 Continued Routine Syntax Description PPollConfig address line sense Configure device for parallel poll PPollUnconfig address Unconfigure device for parallel poll RcvRespMsg address string mode Receive response message ReadStatusByte address Serial poll a device Receive address count mode Receive data from a device ReceiveSetup address Receive setup ResetSys addrlist Reset multiple devices Send address string mode Send data to a device SendCmds string Send command
88. lker terminate a data message by asserting the EOI signal line sending END with the last byte Checking this box causes the NI 488 2 software to assert EOI on the last data byte e 8 bit EOS Along with the designation of an EOS charactaer you can specify whether all eight bits are compared to detect EOS or if just the seven least significant bits ASCII or ISO format are compared to detect EOS EOS Byte You can program some devices to terminate a read operation when a selected character is detected A linefeed character decimal 10 is a popular EOS character National Instruments Corporation 6 9 NI 488 2 User Manual for MacOS Chapter 6 GPIB Configuration Utility Notice that to send the EOS character to a device in a write operation you must explicitly include that byte in your data string Enter the EOS byte 0 to 255 of the bus or device in the EOS Byte editable text box To change the EOS byte click inside the box enter the new number and press the lt return gt key Options for Buses Only Select the device you want to configure from the Bus Device pop up menu The following sections describe the available bus options See also the section Options for Buses or Devices earlier in this chapter Bus Timing This pop up menu appears when configuring a bus associated with a NAT4882 based interface such as the NB GPIB P You can use it to specify the T1 delay of the board source handshake capability This delay dete
89. lude the GPIB commands you need to communicate with it In most cases NI 488 device level calls are sufficient for communicating with instruments Refer to Chapter 2 Developing Your Application for more information Can I use the NI 488 and NI 488 2 calls together in the same application Yes you can mix NI 488 functions and NI 488 2 routines What do I do if I have installed the NI 488 2 software and now my Macintosh crashes upon startup Try changing the name of the NI 488 INIT to ZNI 488 INIT Because INITs load in alphabetical order the ZNI 488 INIT will load last preventing possible corruption from INITs that load after it If changing the name of the NI 488 INIT does not solve the problem another INIT file might have a conflict with the NI 488 INIT Try removing some of your other INIT files You can store them in a temporary folder in case you need to reload them later If you are using System 7 5 or later you can use the Extensions Manager control panel to disable certain extensions and control panels What can I do to check for errors in my GPIB application Examine the value of ibsta after each NI 488 or NI 488 2 call If a call fails the ERR bit of ibsta is set and an error code is stored in ibcnt For more information about global status variables refer to Chapter 2 Developing Your Application How can I use the files located in the Ethernet folder You do not need to use the files in the Ethernet folder
90. lving the SRQ line Although the occurrence of ESRQ warns you of a definite GPIB problem it does not affect GPIB operations except that you cannot depend on the RQS bit while the condition lasts Check to see if other devices not used by your application are asserting SRQ Disconnect them from the GPIB if necessary B 8 National Instruments Corporation ETAB 20 Appendix B Error Codes and Solutions Solutions ELCK 21 ETAB occurs only during the FindLstn FindRQS and ibevent functions ETAB indicates that there was some problem with a table used by the following functions e Inthe case of FindLstn ETAB means that the given table did not have enough room to hold all the addresses of the Listeners found e Inthe case of FindROS ETAB means that none of the devices in the given table were requesting service e In the case of ibevent ETAB means the event queue overflowed and event information was lost In the case of FindLstn increase the size of result arrays In the case of FindRQS check to see if other devices not used by your application are asserting SRQ Disconnect them from the GPIB if necessary In the case of ETAB returned from ibevent call ibevent more often to empty the queue Solutions ELCK occurs if the requested GPIB ENET board or device is being used through another connection Wait for the lock on the board or device to be released or try using ibunlock if you previously used iblock to lo
91. nl 0 0 Compiling Linking and Running C Applications Include the following C statement at the beginning of your application program include decl h The file decl h defines external variables and constants that you can use in your application If your application requires prototypes be sure to include the following statement at the beginning of your application program define PROTOTYPES The GPIB status error and count information are returned in the variables ibsta iberr and ibcnt as described earlier in this chapter Do one of the following based on the type of your application and the type of compiler you are using e For 68k applications compiled under Think C Before compiling add the file MacGPIB68K ThinkC 1ibto your project Add Think C libraries that support toolbox and string functions as well e For 68k applications compiled under Metrowerks CodeWarrior Before compiling add the file MacGPIB68k CodeWarrior lib to your project Add CodeWarrior libraries that support toolbox and string functions as well National Instruments Corporation 2 19 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application e For 68k applications compiled under MPW C Add the file MacGP1IB68k o to the command that links your object module to create the application e For native PowerPC applications Use the MacGPIB sh1b shared library located in the Extensions folder FutureBASIC Applicatio
92. ns Place the following lines at the beginning of your application GLOBALS FutureBASIC GPIB LI GLBL END GLOBALS INCLUDE FutureBASIC GPIB LI LIB NI 488 2 User Manual for MacOS 2 20 National Instruments Corporation Chapter Debugging Your Application This chapter describes several ways to debug your application program Running NI 488 2 Test The software diagnostic test NI 488 2 Test verifies that the NI 488 2 software is installed and functioning with the GPIB board For more information about NI 488 2 Test refer to the getting started manual that came with your GPIB board Debugging with the Global Status Variables After each function call to your NI 488 2 driver ibsta iberr ibcnt and ibcnt1 are updated before the call returns to your application You should check for an error after each GPIB call Refer to Chapter 2 Developing Your Application for more information about how to use these variables within your program to automatically check for errors After you determine which GPIB call is failing and note the corresponding values of the global variables refer to Appendix A Status Word Conditions and Appendix B Error Codes and Solutions These appendixes will help you interpret the state of the driver Debugging with IBIC 488 2 If your application does not automatically check for and display errors you can locate an error by using the Interface Bus Interactive Control utility
93. nt Status bit is part of the IEEE 488 2 defined status byte which is received from a device responding to a serial poll first in first out Group Execute Trigger is the GPIB command used to trigger a device or internal function of an addressed Listener See GTL General Purpose Interface Bus is the common name for the communications interface system defined in ANSI IEEE Standard 488 1 1987 and ANSI IEEE Standard 488 2 1987 The address of a device on the GPIB composed of a primary address MLA and MTA and an optional secondary address MSA The GPIB board has both a GPIB address and an I O address National Instruments Corporation G 3 NI 488 2 User Manual for MacOS Glossary GPIB board Group Executed Trigger GTL H handshake hex high level function Hz ibcnt iberr IBIC 488 2 ibsta IEEE interface message NI 488 2 User Manual for MacOS Refers to the National Instruments family of GPIB interface boards See GET Go To Local is the GPIB command used to place an addressed Listener in local front panel control mode The mechanism used to transfer bytes from the Source Handshake function of one device to the Acceptor Handshake function of another device The three GPIB lines DAV NRFD and NDAC are used in an interlocked fashion to signal the phases of the transfer so that bytes can be sent asynchronously for example without a clock at the speed of the slowest device For more informati
94. nual for MacOS l 4 H handshake lines 1 3 Help Display Help Information function IBIC 488 2 4 17 help frame NI 488 Config utility 6 4 to 6 5 high speed data transfers HS488 5 2 to 5 4 enabling HS488 5 2 to 5 3 system configuration effects 5 3 HS488 See high speed data transfers HS488 HSS488 configuration message 5 3 ibcnt and ibcntl count variables 2 5 ibconfig function configuring GPIB board as CIC 5 2 to 5 3 determining assertion of EOI line 5 2 enabling autopolling 5 6 enabling high speed data transfers 5 2 to 5 3 ibdev function IBIC 488 2 4 12 to 4 14 ibeos function 5 1 ibeot function 5 1 iberr error variable 2 5 IBIC 488 2 auxiliary functions Repeat Previous Function 4 18 Execute Indirect File 4 18 Buffer Set Buffer Display Mode 4 19 Help Display Help Information 4 17 list of functions table 4 16 to 4 17 n Repeat Function n Times 4 18 Set Select Device or Board 4 17 byte count 4 12 debugging applications 3 1 to 3 2 error information 4 11 National Instruments Corporation NI 488 functions commonly used with ibdev 4 12 to 4 14 ibrd 4 14 ibwrt 4 14 NI 488 2 routines commonly used with examples 4 1 to 4 4 Receive 4 16 Send and SendList 4 15 Set 4 15 overview 4 1 status word ibsta 4 11 syntax address syntax 4 5 NI 488 functions 4 6 to 4 9 NI 488 2 routines 4 9 to 4 10 number syntax 4 5 string syntax 4 5 ibppe function conducting paralle
95. ny Address Fax Phone Computer brand Model Processor Operating system include version number Clock speed MHz RAM MB Display adapter Mouse __ yes ___no Other adapters installed Hard disk capacity MB Brand Instruments used National Instruments hardware product model Revision Configuration National Instruments software product Version Configuration The problem is List any error messages The following steps reproduce the problem Documentation Comment Form National Instruments encourages you to comment on the documentation supplied with our products This information helps us provide quality products to meet your needs Title NI 488 2 User Manual for MacOS Edition Date July 1997 Part Number 320897B 01 Please comment on the completeness clarity and organization of the manual If you find errors in the manual please record the page numbers and describe the errors Thank you for your help Name Title Company Address Phone __ Fax ___ Mail to Technical Publications National Instruments Corporation 6504 Bridge Point Parkway Austin TX 78730 5039 Fax to Technical Publications National Instruments Corporation 512 794 5678 Glossary Prefix Meanings Value n nano 10 u micro ig m milli 1
96. o develop a GPIB application program using NI 488 functions and NI 488 2 routines Choosing a Programming Method Programs that need to communicate across the GPIB can access the NI 488 2 driver using the NI 488 2 language interface Using the NI 488 2 Language Interface Your NI 488 2 software includes two distinct sets of subroutines to meet your application needs For most application programs the NI 488 functions are sufficient You should use the NI 488 2 routines if you have a complex configuration with one or more interface boards and multiple devices The following sections discuss some differences between NI 488 functions and NI 488 2 routines Using NI 488 Functions One Device for Each Board If your system has only one device attached to each board the NI 488 functions are probably sufficient for your programming needs Some other factors that make the NI 488 functions more convenient include the following e With NI 488 asynchronous I O functions ibcmda ibrda and ibwrta you can initiate an I O sequence while maintaining control over the CPU for non GPIB tasks e NI 488 functions include built in file transfer functions ibraf and ibwrtf e With NI 488 functions you can control the bus in non typical ways or communicate with non compliant devices National Instruments Corporation 2 1 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application The NI 488 functions consist of high level or d
97. on about handshaking refer to the ANSI IEFE Standard 488 1 1987 Hexadecimal a number represented in base 16 For example decimal 16 hex 10 See device level function Hertz After each NI 488 2 I O function this global variable contains the actual number of bytes transmitted A global variable that contains the specific error code associated with a function call that failed IBIC 488 2 the Interface Bus Interactive Control utility is used to communicate with GPIB devices troubleshoot problems and develop your application At the end of each function call this global variable status word contains status information Institute of Electrical and Electronic Engineers A broadcast message sent from the Controller to all devices and used to manage the GPIB G 4 National Instruments Corporation T O Input Output I O address KB L LAD Listen Address language interface listen address Listener low level function MAV MB memory resident MLA My Listen Address National Instruments Corporation G 5 Glossary In the context of this manual the transmission of commands or messages between the computer via the GPIB board and other devices on the GPIB The address of the GPIB board from the point of view of the CPU as opposed to the GPIB address of the GPIB board Also called port address or board address An Individual Status bit of the status byte used in the Parallel Poll Conf
98. ontrol Utility has an invalid value You can correct it with an ibpad call as shown ibdev 0 66 0x67 7 1 0 id 32256 8100 err cmpl error EARG ud0 ibpad 6 previous value 16 The ibwrt command sends data from one GPIB device to another For example to send the six character data string F3R5T1 from the computer to a device you enter the following string at the prompt as shown in the following example udO ibwrt F3R5T1 0100 cmp1 count 6 The returned status word contains the cmp1 bit which indicates a successful I O completion The byte count 6 indicates that all six characters were sent from the computer and received by the device The ibrd command causes a GPIB device to receive data from another GPIB device The following example acquires data from the device and displays it on the screen in hex format and in its ASCII equivalent along with the status word and byte count ud0 ibrd 20 2100 end cmpl count 18 4e 44 43 56 28 30 30 30 2e 30 30 34 37 45 2b 30 Od Oa NI 488 2 User Manual for MacOS 4 14 NDCV9000 0047E 0 National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility Common NI 488 2 Routines in IBIC 488 2 Following are some common NI 488 2 routines in IBIC 488 2 Set You must use the set command before you can use NI 488 2 routines in IBIC 488 2 The syntax for this form of the set command is as follows set 488 2 n where n represents
99. ontroller A Talker Listener application typically uses ibwait with a mask of 0 to monitor the status of the interface board Then based on the status bits set in ibsta the application takes whatever action is appropriate For example the application could monitor the status bits TACS Talker Active State and LACS Listener Active State to determine when to send data to or receive data from the Controller The application could also monitor the DCAS Device Clear Active State and DTAS Device Trigger Active State bits to determine if the Controller has sent the device clear DCL or SDC or trigger GET messages to the interface board If the application detects a device clear from the Controller it might reset the internal state of message buffers If it detects a trigger message from the Controller the application might begin an operation such as taking a voltage reading if the application is actually acting as a voltmeter Requesting Service Another type of event that might be important in a Talker Listener application is the serial poll A Talker Listener application can call ibrsv with a serial poll response byte when it needs to request service from the Controller Serial Polling You can use serial polling to obtain specific information from GPIB devices when they request service When the GPIB SRQ line is asserted it signals the Controller that a service request is pending The Controller then determines which device assert
100. ough 8 Step 5 Configure the Instrument After initialization the instrument is ready to receive instructions To configure the multimeter use the Send routine to send device specific commands The first argument is the number of the access board The second argument is the GPIB address of the multimeter The third argument is a string of bytes to send to the multimeter The bytes in this example instruct the meter to measure volts alternating current VAC using auto ranging AUTO to wait for a trigger from the Controller before starting a measurement Trigger 2 and to assert SRQ when the measurement has been completed and the meter is ready to send the result SRE 16 The fourth argument represents the number of bytes to be sent The last argument NLend is a constant defined in the header file which tells Send to append a linefeed NI 488 2 User Manual for MacOS 2 16 National Instruments Corporation Chapter 2 Developing Your Application character with EOI asserted to the end of the message sent to the multimeter Send 0 fluke VAC AUTO TRIGGER 2 SR NLend az 16 29L if ibsta amp ERR gpiberr Send setup error Step 6 Trigger the Instrument In the previous step the multimeter was instructed to wait for a trigger before conducting a measurement Now send a trigger command to the multimeter You could use the Trigger routine to accomplish this but because the Fluke 45 is I
101. ping Your Application Choosing a Programming Method cece eeeecceeeeeeseeeseceecaecaeaececeseceseeseseeseaeseeeeas 2 1 Using the NI 488 2 Language Interface ee ec ceeeseceseeseceeeeseeeeeeeeeeeeenes 2 1 Using NI 488 Functions One Device for Each Boatd cece eeeeeeeeeeeees 2 1 NE 488 Device FUNCIONS osim e e ease este 2 2 NI 488 Board Functions cece ceseesececeseeeeceeeeeeceseseeseaeesaecseesaeenees 2 2 National Instruments Corporation v NI 488 2 User Manual for MacOS Using NI 488 2 Routines Multiple Boards and or Multiple Devices 2 3 Checking Status with Global Variables eeeeeeceeeeeeeeeeee 2 3 Status Word ibsta oo eee se cseceecneeseeseeeseesaesaecsaeeseeseseeseseesaesaes 2 3 Error Variable tberricse isss sssiscs ssscctssscsavsnstsssstsnes sbecstanspesststessecsesseees 2 5 Count Variables ibent and ibentl eee ee eeee cee ceseeeeeeeeeeeeeeenee 2 5 Using IBIC 488 2 to Communicate with Devices eee eee eeeeeeceeeeeeeeeeee 2 6 Writing Your NI 488 Application eee csecssececesecesceseeseeesecaaesecsaeeseceeseaeesaeeneeaes 2 6 Items to Include iss ssccncscccssvave suehiagesesstsun ss vecsebebesueeastsnothaachecsgebes ESS 2 6 NI 488 Program Sheller innie soiien dbssevbe es 2 7 General Program Steps and Examples ss esssessssseeseseeeresesrsresrseesrrsreresesrerrerese 2 8 Step T Open a Device spiritose oriee rore soena Sione ESETE ENEKE 2 8 Step 2 Clear the Device niesie iera a e
102. plications 2 20 NI 488 2 software language files 1 8 National Instruments Corporation l 7 Index R ReadStatusByte routine 5 9 Receive routine IBIC 488 2 4 16 REM status word condition A 4 REN remote enable line 1 4 Rename Device option NI 488 Config utility 6 11 repeat addressing enabling in NI 488 Config utility 6 9 required before GPIB activity 3 4 Repeat Function n Times n IBIC 488 2 4 18 Repeat Previous Function IBIC 488 2 4 18 RQS status word condition A 3 S secondary GPIB address definition 1 2 setting in NI 488 Config utility 6 8 Send routine 4 15 SendCmds function 5 3 sending messages across GPIB 1 3 to 1 4 SendList routine 4 15 serial polling 5 5 to 5 9 automatic serial polling 5 6 to 5 7 autopolling and interrupts 5 7 C ON SRQ capability 5 8 stuck SRQ state 5 7 service requests from IEEE 488 devices 5 6 from IEEE 488 2 devices 5 6 Talker Listener applications 5 5 SRQ and serial polling with NI 488 device functions 5 8 with NI 488 2 routines 5 9 NI 488 2 User Manual for MacOS Index service requests serial polling IEEE 488 devices 5 6 IEEE 488 2 devices 5 6 stuck SRQ state 5 7 Talker Listener applications 5 5 Set Select Device or Board function IBIC 488 2 4 17 Set routine IBIC 488 2 4 15 signals and lines ATN attention 1 4 data lines 1 3 DAV data valid 1 3 EOI end or identify 1 4 handshake lines table 1 3 IFC interface clear
103. polling messages However you should use the NI 488 functions for parallel polling when the GPIB board is not the Controller and must configure itself for a parallel poll and set its own individual status bit ist Parallel Polling with NI 488 Functions Follow these steps to implement parallel polling using NI 488 functions Each step contains example code 1 NI 488 2 User Manual for MacOS Configure the device for parallel polling using the ibppc function unless the device can configure itself for parallel polling ibppc requires an 8 bit value to designate the data line number the ist sense and whether or not the function configures or unconfigures the device for the parallel poll The bit pattern is as follows 0131 ES D2 D1 DO E is to disable parallel polling and 0 to enable parallel polling for that particular device S is 1 if the device is to assert the assigned data line when ist 1 and 0 if the device is to assert the assigned data line when ist 0 D2 through DO determine the number of the assigned data line The physical line number is the binary line number plus one For example DIO3 has a binary bit pattern of 010 The following example code configures a device for parallel polling using NI 488 functions The device asserts DIO7 if its ist 0 In this example the ibdev command is used to open a device that has a primary address of 3 has no secondary address has a timeout of 3 s asserts EOI with
104. ptor e An NI 488 2 routine called with an invalid address e PPollConfig called with an invalid data line or sense bit Following are some possible solutions e Make sure that the parameters passed to the NI 488 function or NI 488 2 routine are valid e Do not use a device descriptor in a board function or vice versa B 4 National Instruments Corporation ESAC 5 Appendix B Error Codes and Solutions Solutions EABO 6 Solutions ENEB 7 ESAC results when ibsic ibsre SendIFC or EnableRemote is called when the GPIB board does not have System Controller capability Give the GPIB board System Controller capability by calling ibrsc 1 or by using NI 488 Config to configure that capability into the software EABO indicates that an I O operation has been canceled usually due to a timeout condition Other causes for this error are calling ibstop or receiving the Device Clear message from the CIC while performing an T O operation Frequently the I O is not progressing the Listener is not continuing to handshake or the Talker has stopped talking or the byte count in the call which timed out was more than the other device was expecting Following are some possible solutions e Use the correct byte count in input functions or have the Talker use the END message to signify the end of the transfer e Lengthen the timeout period for the I O operation using ibtmo e Make sure that you have configured your de
105. r use the CIC Protocol method To use the protocol issue the ibconfig function option IbcCICPROT or use the configuration utility to activate the CIC protocol If the interface board is not CIC and you make a device level call with the CIC Protocol enabled the following sequence occurs 1 The GPIB interface board asserts the SRQ line 2 The current CIC serial polls the board 3 The interface board returns a response byte of hex 42 4 The current CIC passes control to the GPIB board If the current CIC does not pass control the NI 488 2 driver returns the ECIC error code to your application This error can occur if the current CIC does not understand the CIC Protocol If this happens you could send a device specific command requesting control for the GPIB board Then use a board level ibwait command to wait for CIC NI 488 2 User Manual for MacOS 5 4 National Instruments Corporation Chapter 5 GPIB Programming Techniques Talker Listener Applications Although designed for Controller In Charge applications you can also use the NI 488 2 software in most non Controller situations These situations are known as Talker Listener applications because the interface board is not the GPIB Controller A typical Talker Listener application waits for events from the Controller and responds as appropriate The following paragraphs describe some programming techniques for Talker Listener applications Waiting for Messages from the C
106. r by examining the error variable iberr Appendix B Error Codes and Solutions describes error codes that are recorded in iberr along with possible solutions ERR is cleared following any call that does not result in an error TIMO dev brd TIMO indicates that the timeout period has been exceeded TIMO is set in the status word following an ibwait call if the TIMO bit of the ibwait mask parameter is set and the time limit expires TIMO is also set following any synchronous I O functions for example ibcmd ibrd ibwrt Receive Send and SendCmds if a timeout occurs during one of these calls TIMO is cleared in all other circumstances END dev brd END indicates either that the GPIB EOI line has been asserted or that the EOS byte has been received if the software is configured to terminate a read on an EOS byte If the GPIB board is performing a shadow handshake as a result of the ibgts function any other function can return a status word with the END bit set if the END condition occurs before or during that call END is cleared when any I O operation is initiated NI 488 2 User Manual for MacOS A 2 National Instruments Corporation SRQI brd Appendix A Status Word Conditions Some applications might need to know the exact I O read termination mode of a read operation EOI by itself the EOS character by itself or EOI plus the EOS character You can use the ibconfig function option IbcEndBitIsNormal to enable
107. r software to obtain support Telephone Fax Australia 03 9879 5166 03 9879 6277 Austria 0662 45 79 90 0 0662 45 79 90 19 Belgium 02 757 00 20 02 757 03 11 Canada Ontario 905 785 0085 905 785 0086 Canada Quebec 514 694 8521 514 694 4399 Denmark 45 76 26 00 45 76 26 02 Finland 09 725 725 11 09 725 725 55 France 01 48 14 24 24 01 48 14 24 14 Germany 089 741 31 30 089 714 60 35 Hong Kong 2645 3186 2686 8505 Israel 03 5734815 03 5734816 Italy 02 413091 02 41309215 Japan 03 5472 2970 03 5472 2977 Korea 02 596 7456 02 596 7455 Mexico 5 520 2635 5 520 3282 Netherlands 0348 433466 0348 430673 Norway 32 84 84 00 32 84 86 00 Singapore 2265886 2265887 Spain 91 640 0085 91 640 0533 Sweden 08 730 49 70 08 730 43 70 Switzerland 056 200 51 51 056 200 51 55 Taiwan 02 377 1200 02 737 4644 United States 512 795 8248 512 794 5678 United Kingdom 01635 523545 01635 523154 Technical Support Form Photocopy this form and update it each time you make changes to your software or hardware and use the completed copy of this form as a reference for your current configuration Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently If you are using any National Instruments hardware or software products related to this problem include the configuration forms from their user manuals Include additional pages if necessary Name Compa
108. re you can skip the first entry in the result array for loop 1 loop lt num_Listeners looptt Send 0 result loop IDN 5L NLend if ibsta amp ERR gpiberr Send error Receive 0 result loop buffer 10L STOPend if ibsta amp ERR gpiberr Receiv rror buffer ibcntl 0O printf The instrument at address d is a s n result loop buffer if strncemp buffer Fluke 45 9 0 fluke result loop printf Found the Fluke n break if loop gt num_Listeners printf Did not find the Fluke n TOOT TOO 3 exit 1 National Instruments Corporation 2 15 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application The constant NLend signals that the new line character with EOI is automatically appended to the data to be sent The constant STOPend indicates that the read is stopped when EOI is detected Step 4 Initialize the Instrument After you find the multimeter use the DevClear routine to clear it The first argument is the GPIB board number The second argument is the GPIB address of the multimeter Then send the IEEE 488 2 reset command to the meter DevClear 0 fluke if ibsta amp ERR gpiberr DevClear error Send 0 fluke RST 4L NLend if ibsta amp ERR gpiberr Send RST error sum 0 0 for m 0 m lt 10 m start of loop for Steps 5 thr
109. ribe characteristics of the devices and boards The device that manages the GPIB by sending interface messages to other devices Central processing unit One of the three GPIB handshake lines See handshake Device Clear is the GPIB command used to reset the device or internal functions of all devices See SDC Decimal See DCL A function that combines several rudimentary board operations into one function so that the user does not have to be concerned with bus management or other GPIB protocol matters The GPIB lines that are used to transmit command or data bytes from one device to another G 2 National Instruments Corporation DMA direct memory access driver E END or END message EOI End or Identify EOS EOS byte EOT ESB FIFO G GET Go To Local GPIB GPIB address Glossary High speed data transfer between the GPIB board and memory that is not handled directly by the CPU Not available on some systems See programmed I O Device driver software installed within the operating system A message that signals the end of a data string END is sent by asserting the GPIB End or Identify EOI line with the last data byte A GPIB line that is used to signal either the last byte of a data message END or the parallel poll Identify IDY message End of string A 7 or 8 bit end of string character that is sent as the last byte of a data message End of transmission The Eve
110. rmines the minimum interval following Ready for Data RFD after which the board may assert Data Valid DAV during a write or command operation If the total length of the GPIB cable in the system is less than 15 m and all devices are on you can choose the sub item Very High 350 ns from the NAT4882 Timing pop up menu For total cable lengths greater than 15 m choose Low 2 us or High 500 ns depending on the maximum capability of your particular device TNT High Speed If you are using a National Instruments TNT4882C based interface such as the NB GPIB P TNT a second item TNT High Speed appears enabled Initially the sub item High Speed Mode Disabled is checked If your device is capable of 1 wire high speed handshaking you can enable the HS488 high speed protocol by choosing the sub item corresponding to the total GPIB cable length of your setup For maximum performance select the sub item GPIB cable is 1 meter DMA When the DMA box is checked direct memory access hardware is used for data transfers freeing the CPU for other work Uncheck the DMA box to transfer data using the CPU DMA channels are allocated for GPIB when you check the DMA box or call the ibdma function with v l in an application program NI 488 2 User Manual for MacOS 6 10 National Instruments Corporation Chapter 6 GPIB Configuration Utility System Controller Generally the NI 488 2 driver is the System Controller SC In some situations such a
111. ronous I O in progress ECAP 11 No capability for operation EFSO 12 File system error EBUS 14 GPIB bus error ESTB 15 Serial poll status byte queue overflow ESRQ 16 SRQ stuck in ON position NI 488 2 User Manual for MacOS 3 2 National Instruments Corporation Chapter 3 Debugging Your Application Table 3 1 GPIB Error Codes Continued Error iberr Mnemonic Value Meaning ETAB 20 Table problem ELCK 21 Board or device is locked Configuration Errors If your hardware and software settings do not match one of the following problems might occur e Application hangs on input or output functions e Data is corrupted If these problems occur make sure that the GPIB hardware settings match the NI 488 2 software settings for the interrupt request level and the DMA channel Refer to the getting started manual that came with your kit for information on hardware and software default settings For instructions on how to view or modify the NI 488 2 software configuration refer to Chapter 6 GPIB Configuration Utility Several applications require customized configuration of the GPIB driver For example you might want to terminate reads on a special end of string character or you might require secondary addressing In these cases you can use either the configuration utility to permanently reconfigure the driver or the NI 488 ibconfig function to programmatically modify the driver while your application
112. routines Each step contains example code 1 National Instruments Corporation Configure the device for parallel polling using the PPol1Config routine unless the device can configure itself for parallel polling The following example configures a device at address 3 to assert data line 5 DIO5 when its ist value is 1 include decl h char response Addr4882_t AddressList 2 The following command clears the GPIB SendIFC 0 The value of sense is compared with the ist bit of the device and determines whether the data line is asserted PPollConfig 0 3 5 1 5 13 NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques NI 488 2 User Manual for MacOS Conduct the parallel poll using PPo11 store the response and check the response for a certain value In the following example because DIOS is asserted by the device if ist 1 the program checks bit 4 hex 10 in the response to determine the value of ist PPoll 0 amp response If response has bit 4 hex 10 set the ist bit of the device at that time is equal to 0 If it does not appear the ist bit is equal to 1 Check the bit in the following statement if response amp 0x10 printf The ist equals 1 n else printf The ist equals 0 n Unconfigure the device for parallel polling using the PPo11Unconfig routine as shown in the following example In this example the NOADDR constant must appear a
113. rs This function takes the device offline and closes the application If the function is declared as follows void gpiberr char msg function prototype then your application invokes the function as follows if ibsta amp ERR gpiberr GPIB error 2 12 National Instruments Corporation Chapter 2 Developing Your Application NI 488 2 Program Shell Figure 2 2 is a flowchart of the steps to create your application program using NI 488 2 routines Ba Initialize Specified GPIB Interface SendIFC Are All Boards Installed Low Level lt figh Level or Low Level Make a High Level Call Send Data to Device Send e Receive Data from Device Receive e Clear Device DevClear e Serial Poll Device ReadStatusByte and so on Finished GPIB Programming Close Board ibon1 Are All Boards Closed Figure 2 2 General Program Shell Using NI 488 2 Routines National Instruments Corporation 2 13 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application General Program Steps and Examples The following steps demonstrate how to use the NI 488 2 routines in your program This example configures a digital multimeter reads 10 voltage measurements and computes the average of these measurements Step 1 Initialization Use the SendIFC routine to initialize the bus and the GPIB interface board so that the GPIB board is Controller
114. s option e Exit q Quit Set Select Device or Board You can use the set command to select 488 2 mode or to communicate with a different device The following example switches communication from using NI 488 2 routines for gpibO to using a unit descriptor ud0 previously acquired by an ibdev call 488 2 0 set udo ud0 Help Display Help Information The help feature displays a menu of topics to choose from Each topic lists relevant functions and other information You can access help for a specific NI 488 function or NI 488 2 routine by typing help followed by the call name for example help ibwrt Help describes the function syntax for all NI 488 functions and NI 488 2 routines National Instruments Corporation 4 17 NI 488 2 User Manual for MacOS Chapter 4 Interface Bus Interactive Control Utility Repeat Previous Function The function repeats the most recent function executed The following example issues an ibsic command and then repeats that same command gpib0 ibsic 0130 cmpl cic atn gpibo 0130 cmpl cic atn n Repeat Function n Times The n function repeats the execution of the specified function n times where n is an integer In the following example the message Hello is sent five times to the device described by ud0 udO 5 ibwrt Hello In the following example the word Hello is sent five times 20 times and then 10 more times ud0 5 ibwrt Hello udO
115. s and for BBS automated information call 512 795 6990 You can access these services at United States 512 794 5422 Up to 14 400 baud 8 data bits 1 stop bit no parity United Kingdom 01635 551422 Up to 9 600 baud 8 data bits 1 stop bit no parity France 01 48 65 15 59 Up to 9 600 baud 8 data bits 1 stop bit no parity FTP Support To access our FTP site log on to our Internet host ftp natinst com as anonymous and use your Internet address such as joesmith anywhere com as your password The support files and documents are located in the support directories National Instruments Corporation C 1 NI 488 2 User Manual for MacOS Fax on Demand Support Fax on Demand is a 24 hour information retrieval system containing a library of documents on a wide range of technical information You can access Fax on Demand from a touch tone telephone at 512 418 1111 E Mail Support currently U S only You can submit technical support questions to the applications engineering team through e mail at the Internet address listed below Remember to include your name address and phone number so we can contact you with solutions and suggestions support natinst com Telephone and Fax Support National Instruments has branch offices all over the world Use the list below to find the technical support number for your country If there is no National Instruments office in your country contact the source from which you purchased you
116. s in a network of computers linked by the GPIB another device might be System Controller Selecting the System Controller box designates the NI 488 2 driver as System Controller Unselecting the box designates that it is not System Controller Each bus can have only one System Controller Assert REN when System Controller Some devices must be in remote state to communicate over the GPIB Checking this box permits the driver to assert the Remote Enable condition REN when it is System Controller placing all instruments subsequently addressed into remote state Unaddressing Some devices must be unaddressed after each data or command transfer To force unaddressing commands to be sent at the end of device functions check the Unaddressing box Unchecking the Unaddressing box slightly improves the performance of your application because unaddressing commands are not sent at the end of device functions Options for Devices Only Select the device you want to configure from the Bus Device pop up menu The device is connected to the bus number that appears in the Use Bus text box The following sections describe the available device options See also the section Options for Buses or Devices earlier in this chapter Rename Device You can rename the device displayed in the Bus Device pop up menu by clicking the Rename Device button and entering the new name This feature is helpful when configuring a large number of devices because th
117. srssrrrrsreersreersresrrersse 5 6 Service Requests from IEEE 488 2 Devices ssssesesssresrssserrrrsrrersrrererreseeese 5 6 Automatic Serial Polling seeeseeeseesscenseneeeeeconeonecoevseessecseeensessenssennsees 5 6 Stuck SRO Statews c4 chin nie aoe ek RATS 5 7 Autopolling and Interrupts eee eeeeeeceseeseceseeseeeeeeeeseeeeseeeneenee 5 7 C ON SRQ Capability 00 0 eee e eio a ee sE es 5 8 SRQ and Serial Polling with NI 488 Device Functions 0 eee eeeeeees 5 8 SRQ and Serial Polling with NI 488 2 Routines oe eee ceeeeeeeeeeeeees 5 9 Example 1 Using FindRQS 5 sc 5sss cssc sscesesseetesessseassateses thes due sotds ss dna tise sstesdeesssntendbetsdeietes 5 10 Example 2 Using AlISpoll se sseescesssenseesseeseneveeesocvencescesseesecssenssevsenstenssessepesverens 5 11 Parallel Polling oinor tienenie anara aaea E rE hee debeas EE ETE E E 5 11 Implementing a Parallel Poll eeeeseeeeeeseeeseseeeeseesrsresssresserrnsenrsseeresresesreseeees 5 11 Parallel Polling with NI 488 Functions 00 eee ceseceeceseeeeeeeeees 5 12 Parallel Polling with NI 488 2 Routines eee eee ce eeteeeeeeeeee 5 13 Chapter 6 GPIB Configuration Utility OVGIVAGW ite ces Been a dis Bae Nee SA E EEE 6 1 Running the Configuration Utility eee csecssecseceseeseceeceeeeeeseeecneeenecaaesaecnesaeeneens 6 1 Opening the Configuration Utility 00 csese cre ceeeeceseeeeceeeeeeeeeeeeeees 6 1 Defa lt Configurations c c sssciseypessepac senses c
118. t 5 set to make itself a Listener Table 1 1 shows the configuration of the GPIB address bits Table 1 1 GPIB Address Bits Bit Position 7 6 5 4 3 2 1 0 Meaning 0 TA LA GPIB Primary Address range 0 to 30 With some With some devices you can use secondary addressing A secondary address is a number in the range hex 60 to hex 7E When secondary addressing is in use the Controller sends the primary talk or listen address of the device followed by the secondary address of the device NI 488 2 User Manual for MacOS 1 2 National Instruments Corporation Chapter 1 Introduction Sending Messages Across the GPIB Devices on the bus communicate by sending messages Signals and lines transfer these messages across the GPIB interface which consists of 16 signal lines and eight ground return shield drain lines The 16 signal lines are discussed in the following sections Data Lines Eight data lines DIO1 through DIO8 carry both data and command messages Handshake Lines Three hardware handshake lines asynchronously control the transfer of message bytes between devices This process is a three wire interlocked handshake and it guarantees that devices send and receive message bytes on the data lines without transmission error Table 1 2 summarizes the GPIB handshake lines Table 1 2 GPIB Handshake Lines Line Description NRFD not ready for data Listening device is ready no
119. t ready to receive a message byte Also used by the Talker to signal high speed transfers HS488 NDAC not data accepted Listening device has has not accepted a message byte DAV data valid Talking device indicates signals on data lines are stable valid data National Instruments Corporation 1 3 NI 488 2 User Manual for MacOS Chapter 1 Introduction Interface Management Lines Five GPIB hardware lines manage the flow of information across the bus Table 1 3 summarizes the GPIB interface management lines Table 1 3 GPIB Interface Management Lines Line Description ATN attention Controller drives ATN true when it sends commands and false when it sends data messages IFC interface clear System Controller drives the IFC line to initialize the bus and make itself CIC REN remote enable System Controller drives the REN line to place devices in remote or local program mode SRQ service request Any device can drive the SRQ line to asynchronously request service from the Controller EOI end or identify Talker uses the EOI line to mark the end of a data message Controller uses the EOI line when it conducts a parallel poll Setting Up and Configuring Your System Devices are usually connected with a cable assembly consisting of a shielded 24 conductor cable with both a plug and receptacle connector at each end With this design you can link de
120. t the end of the array to signal the end of the address list If NOADDR is the only value in the array all devices receive the parallel poll disable message AddressList 0 3 AddressList 1 NOADDR PPollUnconfig 0 AddressList 5 14 National Instruments Corporation Chapter GPIB Configuration Utility This chapter contains instructions for configuring the NI 488 2 software with the NI 488 Config utility Overview You can use the GPIB configuration utility NI 488 Config to view or change the configuration settings of your NI 488 2 software With NI 488 Config you can change the default GPIB settings that your interface board uses to communicate with other devices The utility edits the default GPIB configuration resources in the NI 488 INIT file Help is available on the screen for modifying the current settings For specific information about possible settings refer to the getting started manual that came with your GPIB interface board or box Running the Configuration Utility This section contains information on running the NI 488 Config configuration utility It explains how to use the utility and describes the configuration settings that you can modify Opening the Configuration Utility The NI 488 Config configuration utility appears in the Control Panels folder when you install your NI 488 2 software Open the Control Panels folder by choosing Control Panels from the Apple Icon menu and se
121. tate of all GPIB control lines iblnvv Check for presence of device on the GPIB at pad sad ibloc Go to local ibonl v Place device online or offline ibpad v Change primary address ibppe v Parallel poll configure ibrd v Read data where v is the bytes to read ibrda v Read data asynchronously where v is the bytes to read ibrdf flname Read data to file where f1name is pathname of file to read ibrpp Conduct a parallel poll ibrsc v Request release system control ibrsv v Request service ibsad v Change secondary address ibsic Send interface clear ibsre v Set clear remote enable line ibstop Abort asynchronous operation ibtmo v Change disable time limit NI 488 2 User Manual for MacOS 4 8 National Instruments Corporation Chapter 4 Interface Bus Interactive Control Utility Table 4 2 Syntax for Device Level NI 488 Functions in IBIC 488 2 Continued Syntax Description ibwait mask Wait for selected event where mask is a hex octal or decimal integer or a mask bit mnemonic ibwrt string Write data ibwrta string Write data asynchronously ibwrtf flname Write data from a file where f1name is pathname of file to write IBIC 488 2 Syntax for NI 488 2 Routines Table 4 3 summarizes the syntax of NI 488 2 routines in IBIC 488 2 v represents a number and string represents a string address represents an address and addrlist represents a
122. that does not have the TNT4882C chip the error ECAP is returned Enabling HS488 To enable HS488 for your GPIB board use the ibconfig function option IbcHSCableLength The value passed to ibconfig should specify the number of meters of cable in your GPIB configuration If you specify a cable length that is much smaller than what you actually use the transferred data could become corrupted If you specify a cable length longer than what you actually use the data is transferred successfully but more slowly than if you specified the correct cable length In addition to using ibconfig to configure your GPIB board for HS488 the Controller In Charge must send out GPIB command bytes interface messages to configure other devices for HS488 transfers NI 488 2 User Manual for MacOS 5 2 National Instruments Corporation Chapter 5 GPIB Programming Techniques If you are using device level calls the NI 488 2 software automatically sends the HS488 configuration message to devices If you enabled the HS488 protocol in the configuration utility the NI 488 2 software sends out the HS488 configuration message when you use ibdev to bring a device online If you call ibconfig to change the GPIB cable length the NI 488 2 software sends out the HS488 message again the next time you call a device level function If you are using board level functions or NI 488 2 routines and you want to configure devices for high speed you must send the HS488 con
123. the GPIB board has detected a device clear command DCAS is set whenever the GPIB board detects that the Device Clear DCL command has been sent by another Controller or whenever the GPIB board as a Listener detects that the Selected Device Clear SDC command has been sent by another Controller DCAS is cleared on any call immediately following an ibwait call if the DCAS bit was set in the ibwait mask parameter It also clears on any call immediately following a read or write National Instruments Corporation A 5 NI 488 2 User Manual for MacOS Appendix Error Codes and Solutions This appendix lists a description of each error some conditions under which it might occur and possible solutions The following table lists the GPIB error codes Table B 1 GPIB Error Codes Error iberr Mnemonic Value Meaning EDVR 0 System error ECIC 1 Function requires GPIB board to be CIC ENOL 2 No Listeners on the GPIB EADR 3 GPIB board not addressed correctly EARG 4 Invalid argument to function call ESAC 5 GPIB board not System Controller as required EABO 6 T O operation aborted timeout ENEB 7 Nonexistent GPIB board EDMA 8 No DMA channel available EOIP 10 Asynchronous I O in progress ECAP 11 No capability for operation EFSO 12 File system error EBUS 14 GPIB bus error ESTB 15 Serial poll status byte queue overflow ESRQ 16 SRQ stuck in ON position National Instruments Corpor
124. tions 5 12 to 5 13 using NI 488 2 routines 5 13 to 5 14 PPoll routine 5 14 PPollConfig routine 5 13 PPollUnconfig routine 5 14 primary GPIB address definition 1 2 setting in NI 488 Config utility 6 8 programming See also debugging applications GPIB programming techniques checking status with global variables count variables ibcnt and ibcntl 2 5 error variable iberr 2 5 status word ibsta 2 3 to 2 4 choosing programming method NI 488 2 language interface 2 1 compiling linking and running C applications 2 19 to 2 20 FutureBASIC applications 2 20 National Instruments Corporation Q examples NI 488 2 routines in IBIC 488 2 4 1 to 4 4 IBIC 488 2 for communicating with devices 2 6 NI 488 applications clearing devices 2 8 configuring devices 2 9 items to include 2 6 NI 488 program shell Cillustration 2 7 opening devices 2 8 placing device offline 2 11 processing data 2 11 reading measurements 2 11 triggering devices 2 9 waiting for measurements 2 10 NI 488 2 applications configuring instruments 2 16 to 2 17 finding all Listeners 2 14 identifying instruments 2 15 to 2 16 initialization 2 14 initializing instruments 2 16 items to include 2 12 NI 488 2 program shell illustration 2 13 placing board offline 2 19 processing data 2 19 reading measurements 2 18 triggering instruments 2 17 waiting for measurements 2 17 to 2 18 FutureB ASIC compiling linking and running ap
125. turer defined condition occurs Automatic Serial Polling You can enable automatic serial polling if you want your application to conduct a serial poll automatically any time the SRQ line is asserted You can use autopolling with NI 488 device level calls only The autopolling procedure occurs as follows 1 To enable autopolling use the configuration utility or the configuration function ibconfig with option IbcAUTOPOLL By default autopolling is enabled 2 When the SRQ line is asserted the driver automatically serial polls the open devices 3 Each positive serial poll response bit 6 or hex 40 is set is stored in a queue associated with the device that sent it The RQS bit of the device status word ibsta is set 4 The polling continues until SRQ is unasserted or an error condition is detected NI 488 2 User Manual for MacOS 5 6 National Instruments Corporation Chapter 5 GPIB Programming Techniques 5 Toempty the queue use the ibrsp function ibrsp returns the first queued response Other responses are read in first in first out FIFO fashion If the RQS bit of the status word is not set when ibrsp is called a serial poll is conducted and returns whatever response is received You should empty the queue as soon as an automatic serial poll occurs because responses might be discarded if the queue is full 6 If the RQS bit of the status word is still set after ibrsp is called the response byte queue contains at
126. unction 5 1 NI 488 Config utility EOS Byte option 6 9 to 6 10 EOS Modes option 6 9 EOS comparison method 5 1 EOS read method 5 2 EOS write method 5 1 ERR status word condition A 2 error codes IBIC 488 2 operation 4 11 error codes and solutions debugging applications 3 1 to 3 2 EABO B 5 EADR B 4 EARG B 4 EBUS B 7 ECAP B 7 ECIC B 2 to B 3 EDMA B 6 EDVR B 2 EFSO B 7 ELCK B 9 ENEB B 5 to B 6 ENOL B 3 EOIP B 6 ESAC B 5 ESRQ B 8 ESTB B 8 ETAB B 9 list of error codes table 3 2 to 3 3 B 1 to B 2 error variable iberr 2 5 errors debugging common questions 3 4 to 3 6 communication errors repeat addressing 3 4 termination method 3 4 configuration errors 3 3 GPIB error codes 3 2 to 3 3 timing errors 3 3 to 3 4 National Instruments Corporation l 3 Index ESAC error code B 5 ESRQ error code B 8 ESTB error code B 8 ETAB error code B 9 Event Status bit ESB 5 6 Execute Indirect File function IBIC 488 2 4 18 F FindRQS routine 5 10 functions See IBIC 488 2 NI 488 functions G General Purpose Interface Bus GPIB See GPIB operation global frame NI 488 Config utility 6 5 to 6 6 global variables count variables ibcnt and ibcntl 2 5 debugging applications 3 1 to 3 2 error variable iberr 2 5 status word ibsta 2 3 to 2 4 A 1 to A 5 GPIB addressing See addressing GPIB GPIB configuration utility See NI 488 Config utility GPIB error codes See error
127. us of options The currently selected option is displayed in the box To select an option on the pop up menu click and hold down the mouse button when the cursor is over the box Bus Device A checkbox is a small square box that contains an X when selected and is labeled at the right or on the top An unselected checkbox displays an alert box when E write END on Last Byte clicked A button is a rounded rectangular box EOS Byte 0 An editable text box is a rectangular box labeled to the left Help Frame When you place the cursor over any configuration item a help message for that item appears in the help frame Figure 6 3 shows the default configuration for bus gpib0 The global frame shows the automatic association of bus gpib0 with a GPIB board installed in System slot 3 NuBus slot xB The cursor is positioned over the Auto Configure checkbox and a corresponding help message appears in the help frame NI 488 2 User Manual for MacOS 6 4 National Instruments Corporation Chapter 6 GPIB Configuration Utility N1488 Config National Instruments GPIB Configuration Utility Rg Auto Configure scan bus gpib gt Interface Type NuBus boards Bus Device i LJ oma Primary Address QB system Controler Secondary Address ea Assert REN when System go Unaddressing NAT4882 Timing g Repeat Addressing C Read END on EOS C Write END on EOS it t Byt Configuration Sets
128. us word ibsta which contains information about the state of the GPIB and the GPIB hardware Most of the NI 488 functions return the value stored in ibsta You can test for conditions reported in ibsta to make decisions about continued processing or you can debug your program by checking ibsta after each call ibsta is a 16 bit value A bit value of one 1 indicates that a certain condition is in effect A bit value of zero 0 indicates that the condition is not in effect Each bit in ibsta can be set for NI 488 device calls dev NI 488 board calls and NI 488 2 calls brd or both dev brd Table 2 1 shows the condition that each bit position represents the bit mnemonics and the type of calls for which each bit can be set For a detailed explanation of each of the status conditions refer to Appendix A Status Word Conditions National Instruments Corporation 2 3 NI 488 2 User Manual for MacOS Chapter 2 Developing Your Application Table 2 1 Status Word ibsta Layout Bit Hex Mnemonic Pos Value Type Description ERR 15 8000 dev brd GPIB error TIMO 14 4000 dev brd Time limit exceeded END 13 2000 dev brd END or EOS detected SRQI 12 1000 brd SRQ interrupt received RQS 11 800 dev Device requesting service CMPL 8 100 dev brd T O completed LOK 7 80 brd Lockout State REM 6 40 brd Remote State CIC 5 20 brd Controller In Charge ATN 4 10 brd Attention is asserted TACS 3 8 brd Talker LAC
129. vice level ibwait for RQS e Immediately after a device level NI 488 function is completed before control is returned to the application program National Instruments Corporation 5 7 NI 488 2 User Manual for MacOS Chapter 5 GPIB Programming Techniques C ON SRQ Capability C applications can respond asynchronously to SRQ using the NI 488 ibsrq function This function lets an application specify an SRQ handling routine that is called whenever the NI 488 2 driver detects that the SRQ line is asserted This SRQ handling routine is not an interrupt service routine The driver checks the GPIB SRQ line after any NI 488 function or NI 488 2 routine has completed and if SRQ is asserted and the application has called ibsrq the user defined SRQ handling routine is called SRQ and Serial Polling with NI 488 Device Functions You can use the device level NI 488 function ibrsp to conduct a serial poll ibrsp conducts a single serial poll and returns the serial poll response byte to the application program If automatic serial polling is enabled the application program can use ibwait to suspend program execution until RQS appears in the status word ibsta The program can then call ibrsp to obtain the serial poll response byte The following example illustrates the use of the ibwait and ibrsp functions in a typical SRQ servicing situation when automatic serial polling is enabled include decl h char GetSerialPollResponse int DeviceHan
130. vice to send data before you request data ENEB occurs when there is no GPIB board present This happens when the board is not physically plugged into the system or there is a conflict in the system National Instruments Corporation B 5 NI 488 2 User Manual for MacOS Appendix B Error Codes and Solutions Solutions EDMA 8 Verify that all GPIB interfaces and external controller boxes are plugged in securely powered on and configured properly in the GPIB configuration Solutions EOIP 10 EDMA occurs when the driver is unable to allocate a DMA channel Verify that other boards are not using all seven available DMA channels Disconnect the RTSI connector from the other DMA boards temporarily Solutions NI 488 2 User Manual for MacOS EOIP occurs when an asynchronous I O operation has not finished before some other call is made During asynchronous I O you can only use ibstop ibwait and ibonl or perform other non GPIB operations Once the asynchronous I O has begun further GPIB calls other than ibstop ibwait or ibon1 are strictly limited If a call might interfere with the I O operation in progress the driver returns EOIP Resynchronize the driver and the application before making any further GPIB calls Resynchronization is accomplished by using one of the following three functions e ibwait lf the returned ibsta contains CMPL then the driver and application are resynchronized e ibstop The
131. vices in a linear configuration a star configuration or a combination of the two Figure 1 1 shows the linear and star configurations NI 488 2 User Manual for MacOS 1 4 National Instruments Corporation Chapter 1 Introduction Device A Device D pe ee Device B Device C Linear Configuration Star Configuration Figure 1 1 Linear and Star System Configuration Controlling More Than One Board Multiboard drivers such as the NI 488 2 driver for MacOS can control more than one interface board Figure 1 2 shows an example of a multiboard system configuration gpib0 is the access board for the voltmeter and gpib1 is the access board for the plotter and printer The control functions of the devices automatically access their respective boards National Instruments Corporation 1 5 NI 488 2 User Manual for MacOS Chapter 1 Introduction One GPIB So gagga Digital Voltmeter Plotter Another GPIB Printer Figure 1 2 Example of Multiboard System Setup Configuration Requirements To achieve the high data transfer rate that the GPIB was designed for you must limit the physical distance between devices and the number of devices on the bus The following restrictions are typical e A maximum separation of four meters between any two devices and an average separation of two meters over the entire bus
132. x A Status Word Conditions Appendix B Error Codes and Solutions Appendix C Customer Communication Glossary Index National Instruments Corporation ix NI 488 2 User Manual for MacOS Figures Figure 1 1 Linear and Star System Configuration cece cseesecseeesecneeeeeeeees 1 5 Figure 1 2 Example of Multiboard System Setup eee eee cseeeecseeeeecneeeeeneees 1 6 Figure 1 3 How the NI 488 2 Software Works with Your System ee 1 9 Figure 2 1 General Program Shell Using NI 488 Device Functions 0 000 2 7 Figure 2 2 General Program Shell Using NI 488 2 Routines ee eee eee 2 13 Figure 6 1 Opening Screen of NI 488 Config cece csseeseceseeeeceeeeseseeeeeeeees 6 2 Figure 6 2 Device Default Settings in NI 488 Config cee eseee ene ceteeneees 6 3 Figure 6 3 Help Frame in NI 488 Config cece ceeeeceeceeeeceseeseceeeeeeseeeeseeees 6 5 Figure 6 4 Manual Bus Association in NI 488 Config o eee eee eeeceeeeeneeeseeneees 6 6 Tables Table 1 1 GPIB Address Bits ixi sesc sia svcesoeti ir Ee E E T 1 2 Table 1 2 GPIB Handshake Lines 0 eee iei e e i aE 1 3 Table 1 3 GPIB Interface Management Lines 200 0 eee eeeesseceneeceseeeneeeeneenteeeeneens 1 4 Table 2 1 Status Word ibsta Layout cceeceseesseeeeceeseceeeeceseeceseeeneeceeeeceeeeeeeeee 2 4 Table 3 1 GPIB Error COES r aE tienda a et estes 3 2 Table 4 1 Syntax for Board Level NI 488 Functions in IBIC 488 2 00 eee 4 6 Table 4 2 Syntax for
133. yte you must check to see if the meter has a message to send You can do this by checking the message available MAV bit bit 4 in the status byte if statusByte amp MAVbit gpiberr Improper Status Byte printf Status Byte 0x x n statusByte Step 8 Read the Measurement Use the Receive function to read the measurement over the GPIB The first argument is the GPIB interface board number and the second argument is the GPIB address of the multimeter The third argument is a string into which the Receive function places the data bytes from the multimeter The fourth argument represents the number of bytes to be received The last argument indicates that the Receive message terminates upon receiving a byte accompanied with the END message Receive 0 fluke buffer 10L STOPend if ibsta amp ERR gpiberr Receiv rror buffer ibcnt 0O printf Reading s n buffer sum AsciiToFloat buffer end of loop started in Step 5 NI 488 2 User Manual for MacOS 2 18 National Instruments Corporation Chapter 2 Developing Your Application Step 9 Process the Data Repeat Steps 5 through 8 in a loop until 10 measurements have been read Then print the average of the readings as shown printf The average of the 10 readings is f n sum 10 Step 10 Place the Board Offline Before ending your application program take the board offline using the ibon1 function ibo

NI-488.2 User Manual for MacOS

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