National Instruments GPIB
Contents
1. 7 Schematic Diagram ets ugue 1 GPIB 100A Parts Locator Diagram sse C 1 Appendix D Cable Assembly Wire D 1 Appendix E Interface 222 22 2 2 220002100000000000000004 E 1 Appendix F Key soos cS sed Re cee ales ete 1 GPIB 100A User Manual viii National Instruments Corporation Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Table Table Table Table Table Table Table Table Contents Figures 1 1 The Model GPIB 100A Bus 1 1 1 2 Typical GPIB 100A Extension System Physical Configuration 1 2 1 3 Typical GPIB 100A Extension System Logical Configuration 1 2 Ps NB TOES edic E 2 1 3 1 Switch Settings for Operating Mode 3 2 3 2 Switch Settings for Parallel Poll Response Mode eese 3 4 4 1 GPIB 100A Block DIAgtatn 4 1 GPIB Cable Connector us ouo ie rot Machi pe de cea e A 3 2 Linear Configuration of the GPIB Devices eee A 5 3 Star Configuration of GPIB Devices A 6 C 1 GPIB 100A Parts Locator Diagram C 1 Tables l 1 System Configu2. SCHEMATIC DIAGRAM GPIB 00A 7802 32 0 8 65 7 99 TE i TENT NO DRAWING NEXT ASSY APPLICATION DO SCALE DRAWING Appendix GPIB 100A Parts Locator Diagram This appendix contains the parts locator diagram for the GPIB 100A parts locator diagram shows the locations of the GPIB 100A configuration jumpers and switches 1 2 1985 180235 01 SERNO o c CABLE GROUND SHIELD ISOLATION JUMPER o o o o a 9 a 9 3 o 0 0 0 0 0 0 vosi ds 15151 da 29157 4 265192 js 14651 d 265192 ds 5 c 25519 45 c 265192 45 21 623 C24 25 c26 c30 c Lo C i2 c c o 8051 Gr 8051 d 9851 gt 8051 c vos ds a Lj o 1875 4 a 0 0 0 a c o e 62251 4 i vos do do ro ho a 08 c 151 d c o c e S1 d 2057 da d 2 Figure C 1 GPIB 100A Parts Locator Diagram National Instruments Corporation C 1 GPIB 100A User Manual Appendix D Cable Assembly Wire List This appendix contains the wire list for the GPIB 100A Transmission Cable National Instruments Corporation D 1 GPIB 100A U
3. 4 2 source Handshake POUR ded e UNAM Ge 4 2 Parallel Polling iL 4 3 Data Direction 4 4 4 4 National Instruments Corporation vii GPIB 100A User Manual Contents Appendix A Operation of the G PUB A 1 eres 1 TYPOS Of MESSASES 1 Talkers Listeners and nennen eene eene 1 System Controller and Active Controller eese A 2 P 2 Data Tames T AE A 3 Handshake nu Aen ER A 3 NRED not ready for data ce ts A 3 55 200 o Vest dus i utc dun dt 4 datacvalad ade oh tds A RE 4 4 ASTIN ALTE Wi OTI 4 interface Clear 4 REN iH EE 4 RC SERVICE TEQUESE acuto 4 end r id ntify 4 Physical and Electrical Characteristics eiecit nennen onte nennen A 5 Confieuration TUR S
4. National Instruments Corporation Chapter 3 Configuration and Operation Users who are unfamiliar with the GPIB should first read Appendix A Operation of the GPIB to become familiar with GPIB terminology and protocol In the following discussions the terms ocal and remote refer to certain states of the two GPIB 100A Bus Extenders in the system When one extender is in a local state meaning that the state in question originated on the local state s side the other extender is in the corresponding remote state The three states in question are the System Controller Active Controller and Source Handshake states Operating Modes The GPIB 100A has two operating modes Talker Listener Controller mode and Talker Listener mode Both units in the extension system must be set to the same mode Talker Listener Controller TLC Mode The 100 is set at the factory to the more common TLC operating mode The TLC mode requires a System Controller on one side of the extension There may be any number of Talkers Listeners and other Controllers in the system In the TLC mode the two GPIB 100As expect to see in order first the Interface Clear IFC signal from the System Controller second the Attention ATN signal from the Active Controller and third the Data Valid DAV signal from the Active Controller or Talker A brief description of this mode is in the following paragraph Both units power up in a quiescent condition with no l
5. 15 16 17 31 33 29 12 a Appendix E Multiline Interface Command Messages The following tables are multiline interface messages sent and received with ATN TRUE National Instruments Corporation 1 GPIB 100A User Manual Multiline Interface Command Messages Oct Dec 000 0 001 1 002 2 003 3 004 4 005 5 006 6 007 7 010 8 011 9 012 10 013 11 014 12 015 13 016 14 017 15 020 16 021 17 022 18 023 19 024 20 025 21 026 22 027 23 030 24 031 25 032 26 033 27 034 28 035 29 036 30 037 3 Appendix E Multiline Interface Messages ASCII NUL SOH STX ETX EOT ENQ ACK BEL DLE Message Definitions DCL GET GTL LLO MLA Device Clear Group Execute Trigger Go To Local Local Lockout My Listen Address GPIB 100A User Manual Msg GTL SDC PPC GET TCT LLO DCL PPU SPE SPD Hex Oct Dec ASCII Msg 20 040 21 041 22 042 23 043 24 044 25 045 26 046 27 047 28 050 29 051 052 2B 053 2C 054 2D 055 2 056 2 057 30 060 31 061 32 062 33 063 34 064 35 065 36 066 37 067 38 070 39 071 3A 072 3B 073 3C 074 3D 075 076 077 5 PPD 32 SP MLAO 33 MLAI 34 4 MLA2 35 36 4 37 5 38 amp MLA6 39 7 40 8 41 MLA9 42 m MLAIO 43 11 44 12 45 46 MLA14 47 15 48 0 MLAI6 49 1 MLA17 50 2 MLAIS8 51 3 MLAI9 32 4 MLA20 53
6. National Instruments Corporation Appendix A Operation of the GPIB Physical and Electrical Characteristics Devices are usually connected with a cable assembly consisting of a shielded 24 conductor cable with both a plug and receptacle at each end This design allows devices to be connected in either a linear or a star configuration or a combination of the two See Figures A 2 and A 3 Figure A 2 Linear Configuration of the GPIB Devices National Instruments Corporation A 5 GPIB 100A User Manual Operation the GPIB Appendix A Figure 3 Star Configuration of GPIB Devices The standard connector is the Amphenol or Cinch Series 57 MICRORIBBON or AMP CHAMP type An adapter cable using non standard cable and or connector is used for special interconnect applications The GPIB uses negative logic with standard TTL logic levels When DAV is true for example it is a TTL low level 0 8 V and when DAV is false it is a TTL high level 2 2 0 V GPIB 100A User Manual A 6 National Instruments Corporation Appendix Operation of the GPIB Configuration Restrictions To achieve the high data transfer rate that the GPIB is designed for the physical distance between devices and the number of devices on the bus is limited The following restrictions are typical Amaximum separation of 4 m between any two devices and an average separation of 2 over the entire bus maximum total cable length of 20 m
7. No more than 15 devices connected to each bus with at least two thirds powered on It is usually possible to connect a cluster of lab instruments without exceeding these restrictions But many applications require longer cable spans or additional loading From the time the GPIB was invented the need has existed for bus extenders and expanders repeaters Extenders connect two separate buses via a transmission medium and the distance between the buses can be quite long Expanders allow up to 14 additional devices to be connected to the bus and 20 meters of cable length to be added to the system National Instruments provides two extenders which allow longer cable spans These products are the GPIB 100A and the GPIB 110 Both must be used in pairs one at each end of the extension cable The GPIB 100A a parallel extender relays the instantaneous status of all GPIB signals over an RS 422 compatible cable The GPIB 100A allows up to a 300 meter extension The GPIB 110 a serial extender samples the GPIB signals encodes the information into small packets and transmits the packets on either a low cost coaxial cable or a high performance electrically isolated fiber optic cable The GPIB 110 allows up to a 2 kilometer extension The GPIB 100A is the only parallel extender on the market today The instantaneous status of all GPIB signals on one side are relayed over individual RS 422 circuits to the other side This approach makes the GPIB 100A the
8. Listener TL Mode There is no Controller and only one Talker in the TL mode of operation sometimes called talk only mode Usually there is just one Listener as well In the TL mode the System and Active Controller states remain inactive and the IFC REN ATN and SRQ signals are unused The directions of the other signals are set the first time the Talker asserts DAV Setting the Operating Mode Both GPIB 100As in the extension system must be set to the same operating mode Use switch 51 position 1 on the back panel of each GPIB 100A to set the operating mode Set the switches as shown in Figure 3 1 A Talker Listener Controller Mode B Talker Listener Mode represents the side of the switch you press down Figure 3 1 Switch Settings for Operating Mode Parallel Poll Response PPR Modes According to ANSI IEEE Standard 488 1978 devices must respond to a parallel poll within 200 nsec after the Identify IDY message Attention and End Or Identify EOD is asserted by the Active Controller which then waits until 2 usec or more to read the Parallel Poll Response PPR It is not possible for a remote device on an extended system to respond to this quickly because of cable propagation delay GPIB extender manufacturers have approached this in three ways Approach 1 Respond to IDY within 200 nsec with the results of the previous poll of the remote bus Approach 2 Ignore the 200 nsec rule and assume the Controller will
9. 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 PURPOSE 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 Instrument 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 Copyright Under the copyright laws this book may not be copied ph
10. contains descriptions of how the GPIB 100A circuitry operates Appendix A Operation of the GPIB describes GPIB terminology and protocol for users unfamiliar with the GPIB Appendix B Schematic Diagram contains a detailed schematic diagram of the GPIB 100A Appendix C GPIB 100A Parts Locator Diagram contains the parts locator diagram for the GPIB 100A Appendix D Cable Assembly Wire List contains the listing of wire connections for the GPIB 100A transmission cable Appendix E Multiline Interface Messages contains an ASCII chart and a list of the corresponding GPIB messages Appendix F Mnemonics Key contains a mnemonics key that defines the mnemonics used throughout the manual Related Document The following document is a reference that covers in greater detail specific topics introduced in this manual e ANSI IEEE Standard 488 1978 IEEE Standard Digital Interface for Programmable Instrumentation National Instruments Corporation GPIB 100A User Manual Preface Abbreviations Used in the Manual The following abbreviations are used in the text of this manual C Hz in kbytes mA Mbytes usec nsec sec VAC GPIB 100A User Manual centigrade Fahrenheit hertz inch thousand bytes meter milliamperes million bytes millimeter microsecond nanosecond second volts Volts Alternating Current watt vi National Instruments Corporation Contents Chapter 1 Description
11. of the GPIB 100A 7 1 1 Introductions nios toot Sean cp 1 1 100 8 1 3 Chapter 2 Ea 2 1 PIS PE CUO 2 1 Power 2 1 Groundimneg NERO 2 2 Disassembly ncuei ng 2 2 Mounin e en 2 2 Connecting to Hewlett Packard Controllers 2 2 Chapter 3 Configuration and Operation sse 3 1 Operating 3 1 Talker Listener Controller TLC 3 1 Talker Listen r TE doa ford 3 2 Setting the Operating sitos stes e RI Et eu emnes 3 2 Parallel Poll Response PPR docte etae ee a ane te p a eade 3 2 Buffered PPR Mode Approach 1 3 3 Unbuffered PPR Mode Approach 2 Lotte 3 3 Mixer Mode Operation minea rete 3 4 Operating the GPIB 100A 5 3 4 Chapter 4 Theory of OpDerallon tek Pon cab os 4 1 ERE RITE LS ERN 4 1 Pi Were OD 4 1 System Controller Deteetloti 4 2 Active Controller pe
12. on the System Controller last after the extenders and all other devices are operating This is necessary if the System Controller executes only one IFC shortly after power on The preferred operating mode is to keep both extenders and at least two thirds of the devices on both buses powered on when there is any GPIB activity GPIB 100A User Manual 3 4 National Instruments Corporation Chapter 4 Theory of Operation Diagrams Figure 4 1 shows a block diagram for the GPIB 100A Refer to Appendix B for GPIB 100A schematic diagrams and Appendix C for the GPIB 100A parts locator diagram RIFC System Controller Detection BUS REN 4 RATN Active Controller 4 BUS SRQ boh RS 422 etection Drivers L M and M Receivers y XRFD Source Handshake a 4 RRFD Detection and Handshake Control gt BUS NDAC xeo SEES 67 Data Direction Parallel Poll RRON Control Control BUF UNBUF PPR 85 422 Receivers Parallel Poll Response Register GPIB Tranceivers RS 422 Drivers Figure 4 1 GPIB 100A Block Diagram Power On When the GPIB 100A is powered on a reset pulse PON created by U48F U28A D and associated Register Capacitor Delay RCD network directly or indirectly clears all flip flops FFs to an initialized state PON remains active until both units in the extension are powered on National I
13. wait sufficiently long to capture the response Approach 3 Do not support parallel polling at all The GPIB 100A uses either Approach 1 or 2 selected at switch 51 position 3 Set this switch as shown in Figure 3 2 GPIB 100A User Manual 3 2 National Instruments Corporation Chapter 3 Configuration and Operation Buffered PPR Mode Approach 1 Most Controllers pulse IDY signal for a period of time exceeding 2 usec and expect a response within that time When used with this type of Controller the GPIB 100A should be left in the Buffered PPR mode as set at the factory In this mode the local 100 extender responds to IDY by outputting the contents of the PPR data register At the same time a parallel poll message is sent to the remote bus and the poll response is returned to the local unit in due course When the local IDY signal is unasserted the register is loaded with the new remote response Consequently the register contains the response of the previous poll To obtain the response of both local and remote buses the control program executes two parallel polls back to back and uses the second response The software driver library of most Controllers contains an easy to use parallel poll function If for example the function is called PPOLL and the control program is written in BASIC the sequence to conduct a poll in Buffered PPR mode might be like this CALL PPOLL PPR CALL PPOLL PPR IF PPR gt 0 GOTO NN
14. 00 m and the loading limit to 30 devices including the extenders without sacrificing speed or performance These point to point extender systems can be connected in series for longer distances or in star patterns for additional loading At short distances the data transfer rate over the extension can exceed 250 kbytes sec degrading with distance only by the propagation delay along the cable Furthermore regardless of the distance there is no speed degradation at all for transfers between devices on the same side of the National Instruments Corporation 1 1 GPIB 100A User Manual Description of the GPIB 100A Chapter 1 extension And because the GPIB 100A is a functionally transparent extender the same GPIB communications and control programs that work with an unextended system will work unmodified with an extended system There is one minor exception to this transparency in conducting parallel polls as explained in Chapter 3 in the paragraph Parallel Poll Response PPR Modes RS 232 Compatible Transmission Lines GPIB 1 GPIB 100A GPIB 100A GPIB 2 Computer Printer Multimeter Signal Generator Listener Talker and Listener Listener Unit Under Test Figure 1 2 Typical GPIB 100A Extension System Physical Configuration Computer Printer Multimeter Signal Generator Listener Talker and Listener Listener System Controller Talker and Listener Unit Under Test Figure 1 3 Typical GPIB 100A Ex
15. 1 89 Y MTA25 79 171 121 MSA25 PPD 132 90 7 26 172 122 7 MSA26 PPD 5B 133 91 27 7B 173 123 MSA27 PPD 5C 134 92 MTA28 7 174 124 MSA28 PPD 5D 135 93 MTA29 7D 175 125 MSA29 PPD 5 136 94 A MTA30 7E 176 126 MSA30 PPD 5F 137 95 _ UNT 177 127 DEL PPE Parallel Poll Enable SPE Serial Poll Enable PPU Parallel Poll Unconfigure TCT Take Control SDC Selected Device Clear UNL Unlisten SPD Serial Poll Disable UNT Untalk National Instruments Corporation E 3 GPIB 100A User Manual Appendix F Mnemonics Key This appendix contains a mnemonics key that defines the mnemonics abbreviations used throughout this manual Mnemonic ASCII ATN C CIC DAV DIO EOI FF IDY IFC ISO LAC LS LSC NDAC NRFD PON PP PPR RAC RCD National Instruments Corporation Definition American Standard Code for Information Interchange Attention Controller Controller In Charge Bit Data Valid Data End or Identify Bit Flip flop Identify Interface Clear International Standard code set Listener Local Active Controller Local Source Local System Controller GPIB Not Data Accepted line status Bit GPIB Not Ready For Data line status Bit Power On Reset Pulse Parallel Poll scan all status flags Parallel Poll Response Remote Active Controller Resistor Capacitor Delay F GPIB 100A User Manual Mnemonics Key Mnemonic REN RFD RR RS RSC SRQ TLC GPIB 100A User Ma
16. 5 MLA21 54 6 MLA22 35 7 MLA23 56 8 MLA24 57 9 MLA25 58 MLA26 59 MLA27 60 lt MLA28 61 MLA29 62 gt MLA30 63 P UNL My Secondary Address My Talk Address Parallel Poll Configure Parallel Poll Disable National Instruments Corporation Appendix E Multiline Interface Command Messages Multiline Interface Messages Hex Oct Dec ASCII Msg Hex Oct Dec Msg 40 100 64 60 140 96 E MSAO PPE 41 101 65 A MTAI 61 141 97 a MSAI PPE 42 102 66 B MTA2 62 142 98 b MSA2 PPE 43 103 67 63 143 99 MS 44 104 68 4 64 144 100 MSAA PPE 45 105 69 E 5 65 145 101 MSAS PPE 46 106 70 MTA6 66 146 102 f MSA6 PPE 47 107 71 G MTA7 67 147 103 g MSA7 PPE 48 110 72 H MTA8 68 150 104 h MSA8 PPE 49 111 73 I 9 69 151 105 1 MSA9 PPE 4A 112 74 J 10 6A 152 106 MSAIO PPE 4B 113 75 K 1 6B 153 107 k MSA11 PPE 4C 114 76 L 12 6 154 108 1 MSA12 PPE 4D 115 77 MTA13 6D 155 109 m MSA13 PPE 4E 116 78 N 14 6 156 110 n MSA14 PPE 4F 117 79 15 6 157 111 MSAIS PPE 50 120 80 16 70 160 112 MSA16 PPD 51 121 81 17 71 161 113 4 MSA17 PPD 52 122 82 R 18 72 162 114 r MSA18 PPD 53 123 83 5 19 73 163 115 8 MSA19 PPD 54 124 84 T MTA20 74 164 116 t MSA20 PPD 55 125 85 U 21 75 165 117 u MSA21 PPD 56 126 86 V MTA22 76 166 118 V MSA22 PPD 57 127 87 W MTA23 TI 167 119 W MSA23 PPD 58 130 88 X 24 78 170 120 x MSA24 PPD 59 13
17. AC indicates when a device has or has not accepted a message byte The line is driven by all devices when receiving commands and by Listeners when receiving data messages DAV data valid DAV tells when the signals on the data lines are stable valid and can be accepted safely by devices The Controller drives DAV when sending commands and the Talker drives it when sending data messages The way in which NRFD and NDAC are used by the receiving device is called the Acceptor Handshake Likewise the sending device uses DAV in the Source Handshake Interface Management Lines Five lines are used to manage the flow of information across the interface attention Controller drives ATN true when it uses the data lines to send commands and false when it allows a Talker to send data messages IFC interface clear The System Controller drives the IFC line to initialize the bus to become Controller In Charge REN remote enable The System Controller drives the REN line which is used 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 Active Controller with the SRQ line EOI end or identify The EOI line has two purposes The Talker uses the EOI line to mark the end of a message string The Active Controller uses the EOI line to tell devices to identify their responses in a parallel poll GPIB 100A User Manual A 4
18. GPIB 100A User Manual March 1990 Edition Part Number 320063 01 Copyright 1985 1991 National Instruments Corporation Rights Reserved National Instruments Corporation 6504 Bridge Point Parkway Austin TX 78730 5039 512 794 0100 800 IEEE 488 toll free U S and Canada Technical support fax 512 794 5678 Limited Warranty The GPIB 100A is warranted against defects in materials and workmanship for a period of two years from the date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace equipment that proves to be defective during the warranty period This warranty includes parts and labor 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
19. N If two GPIB extender systems are connected in series three polls are necessary to get responses from the local middle and far buses Unbuffered PPR Mode Approach 2 Many Hewlett Packard GPIB Controllers remain in a parallel poll state with IDY asserted whenever they are not performing another function A change in the response causes an interrupt of the control program In other Controllers the IDY signal is toggled on and off and the duration of the signal can be varied to accommodate delayed responses over extenders When used with these types of Controllers the GPIB 100A should be set to Unbuffered PPR mode This means that the IDY message is sent to the remote bus and the response is returned as fast as propagation delays allow The Controller must allow time to receive the response National Instruments Corporation 3 3 GPIB 100A User Manual Configuration and Operation Chapter 3 Mixed Mode Operation If there are multiple Controllers and all of the same type are located on the same side of the extension the two GPIB 100A units can be set to Unbuffered and Buffered PPR modes accordingly UNBUF A Unbuffered PPR Mode B Buffered PPR Mode represents the side of the switch you press down Figure 3 2 Switch Settings for Parallel Poll Response Mode Operating the GPIB 100A System The GPIB 100A extension system is fully operational when power is applied to both units In TLC mode it is sometimes necessary to power
20. drivers 05 and U7 if there is a remote parallel poll in progress U37D and U27B or if the LS FF is set and a local parallel poll is not in progress U47C and U26A Otherwise these lines are not driven EOI The local unit transmits EOI to the remote side as XEOI if the LS FF 15 set transceiver U1A U25B U46B and driver U30C Furthermore XEOI is asserted from the start of a local parallel poll until the poll handshake signal BUS PP is received from the remote unit and the local poll stops is received as REOI at the remote unit through receiver U19B It propagates to the remote GPIB if the local unit is conducting a parallel poll U27A B 7 and transceiver U1A or if the RS remote response RR is set and the local unit is not conducting a poll 47 GPIB 100A User Manual 4 4 National Instruments Corporation Appendix A Operation of the GPIB History of the GPIB The GPIB is a link bus or interface system through which interconnected electronic devices communicate Hewlett Packard invented the GPIB which they call the HP IB to connect and control programmable instruments manufactured by them Because of its high system data rate ceilings of from 250 kbytes sec to 1 Mbytes sec per second the GPIB quickly became popular in other applications such as intercomputer communication and peripheral control It was later accepted as the industry standard IEEE 488 The versatility of the system prompted the name General P
21. embly near the back panel Disassembly The case consists of two identical sections Before disassembling remove power from the unit Then remove the two screws on each side of the case and lift the top section When reassembling it may be necessary to adjust the two trim panels on the case side for proper fit in their grooves Mounting The GPIB 100A enclosure is designed for table top operation or for rack mounting Single and dual unit rack mounting kits are available from National Instruments for field installation Connecting to Hewlett Packard Controllers To achieve very high data transfer rates and long cable spans between devices many Hewlett Packard HP controllers and computers such as the 64000 series use a preload technique on the unit designated Master Controller When preloaded the GPIB lines of the Master Controller are terminated to represent six device loads HP has two types of preloading Class A in which all 16 GPIB lines are loaded and Class B in which all lines except Not Ready For Data NRFD and Not Data Accepted NDAC are loaded Preloading increases ringing on signal transitions and may cause improper operation of the GPIB 100As If this happens all signals on the Master Controller should be set to normal 1 unit load This is done by means of a back panel switch when working from the exterior In addition the cabling rule of no more than 2m device must be strictly enforced GPIB 100A User Manual 2 2
22. fastest and most transparent of all extenders available The parallel design however requires bulkier and more costly cable than serial designs National Instruments Corporation A 7 GPIB 100A User Manual Appendix B Schematic Diagram This appendix contains the schematic diagram for the GPIB 100A National Instruments Corporation B 1 GPIB 100A User Manual REVISIONS TIR DESCRIPTION DATE eun RELEASED 5 OPEN I CLOSED TALKER LISTENER TALKERILISTENER CONTROLLER PARALLEL POLL RESPONSE UNBUFFERED BUFFERED 3 erre 890 5 920a Sp EIS Sea ele dos uio 262832 i AeA 8 6 85 6 014 15157 b Pa Es Labs lo Do Jo Xo 06 j On D 1 d On ow of Ma Y 4 4 4 4 35 6 SOY j L zm EA Jo e SR E Ye Raha Xn Yo R Xe Xe RaRa e PARTS LIST n aed A REIN EET PU TOLERANCES ARE NATIONAL INSTRUMENTS AUSTIN TX 42 344 Dc T v FRACTIONS ANGUS On Oo t 4 u1 _ 4
23. ification complete Acceptor Handshake codes complete Talker complete Listener complete Service Request complete Remote Local complete Parallel Poll complete Device Clear complete Device Trigger complete Controller open collector GPIB drivers Table 1 3 Operating Characteristics Characteristic Specification architecture asynchronous no clock parallel design point to point not multi drop transmission operating modes Talker Listener Controller or Talker Listener Talk Only Parallel Poll Response Buffered Parallel Poll Response or modes Unbuffered Parallel Poll Response GPIB 100A User Manual 1 4 National Instruments Corporation Chapter 1 Description of the GPIB 100A Table 1 4 Electrical Characteristics Characteristic Specification GPIB interface circuit duplex transceivers with open collector drivers MC3441A transmission interface RS 422 drivers and receivers circuit MC3487 and AM26LS32 connected with patented data transmission cable for minimum skewing lt 3 between any two pairs power supply 50 to 60 Hz selectable fuse 110 V 160 mA 250 mA 250 V Slow Blow 220 V 80 mA 200 mA 250 V Slow Blow GPIB interface load one standard load AC and DC Table 1 5 Environmental Characteristics Characteristic Specification 5 to 95 non condensing conditions 110V Version UL Listed 220V Version UL Listed and also classified by Underwriters Laboratories Inc in accordance with Internationa
24. ipment Power Connection The GPIB 100A Bus Extender is shipped from the factory set at a certain operating voltage either 110 VAC or 220 VAC Verify that the voltage you are using is the same as that selected on the rear panel of the GPIB 100A Operating at a voltage other than the one selected may damage the unit If the GPIB 100A is set at a voltage other than the one you are using follow the steps below to change the operating voltage 1 Remove the power cord from the unit 2 Pull out the fuse holder and replace the fuse with one that has the type and rating specified in Table 1 4 for your operating voltage 3 Using a small flat head screwdriver rotate the voltage selector to point to your operating voltage ex N LINE TRANSMISSIO 2 uw a Figure 2 1 Voltage Selection National Instruments Corporation 2 1 GPIB 100A User Manual Installation Chapter 2 Grounding Configuration A U S standard three wire power cable is provided with the GPIB 100A When connected to a power source this cable connects the equipment chassis to the power ground The GPIB 100A is shipped from the factory with chassis and power grounds connected to the logic ground of the digital circuitry and the shields of the interfacing cables If it is necessary to isolate these grounds to prevent current loops between units disassemble the unit according to the following instructions and remove jumper W1 located on the circuit card ass
25. l Electrotechnical Commission publication 950 National Instruments Corporation 1 5 GPIB 100A User Manual Description of the GPIB 100A Chapter 1 Table 1 6 Physical Characteristics 35x 85x 13 in 89 x 216 x 330 mm case material UL94V 0 flame retardant polystyrene Dow 60875 F or equivalent GPIB cable Hewlett Packard 10833 style or equivalent Transmission cable Dynatronics D 200 24 cable with AMP Amplimite connectors AMP HDP 20 50 pin connector with RFI EMI shield Table 1 7 Components and Accessories Model GPIB 100A Bus Extender 110V 776107 01 two required per extension Model GPIB 100A Bus Extender 220V 776107 31 two required per extension Type T2 Transmission Cable 178056 xxx xxx length in meters Type X2 GPIB Cable 1 meter 763061 01 2 meters 763061 02 4 meters 763061 03 Single Rack Mount Kit 180304 01 Dual Rack Mount Kit 180304 02 Note part numbers in this table are National Instruments part numbers GPIB 100A User Manual 1 6 National Instruments Corporation Chapter 2 Installation Inspection Inspect the shipping container and contents for evidence of physical damage or stress If damage is discovered and appears to have been caused in shipment file a claim with the carrier If the equipment is damaged do not attempt to operate it before contacting National Instruments for instructions Retain the shipping material for possible inspection by carrier or reshipment of the equ
26. lone devices interconnected via a cable bus National Instruments Corporation A 1 GPIB 100A User Manual Operation the GPIB Appendix A The role of the GPIB Controller can also be compared to the role of the computer s CPU but a better analogy is to the switching center of a city telephone system The switching center Controller monitors the communications network GPIB When the center Controller notices that a party device wants to make a call send a data message it connects the caller Talker to the receiver Listener The Controller usually addresses a Talker and a Listener before the Talker can send its message to the Listener After the message is transmitted the Controller usually unaddresses both devices Some bus configurations do not require a Controller For example one device may only be a Talker called a Talk only device and there may be one or more Listen only devices A Controller is necessary when the active or addressed Talker or Listener must be changed The Controller function is usually handled by a computer System Controller and Active Controller Although there can be multiple Controllers on the GPIB only one Controller at a time is Active Controller or Controller in Charge CIC Active control can be passed from the current Active Controller to an idle Controller Only one device on the bus the System Controller can make itself the Active Controller GPIB Signals The interface bus con
27. nstruments Corporation 4 GPIB 100A User Manual Theory of Operation Chapter 4 System Controller Detection PON initializes FFs U22A and U12A to clear the Remote System Controller RSC and Local System Controller LSC signals When Interface Clear IFC is received from the local side via GPIB transceiver U2B the LSC FF is set on the leading edge of IFC and after a delay through U21B C D E IFC is enabled U35D to the remote unit as XIFC through driver U29A LSC enables the local unit to transmit Remote Enable REN to the remote unit through driver U8A XIFC becomes RIFC on the remote side and is received through U10D and propagated to the remote GPIB through transceiver U2B where the bus signal is received back to clock the RSC FF U22A RSC enables REN U32C to be driven on the remote GPIB through transceiver U2D Active Controller Detection The Remote Active Controller RAC and Local Active Controller LAC FFs U22B and U12B remain cleared until either RSC or LSC is set via U41B that is until the System Controller has been located After a short delay U21 A F and U31B F the Attention receiver on the local side U32D is enabled This delay allows the LAC FF to be set if ATN is already asserted when IFC occurs When ATN is received from the local side via transceiver U2C the LAC FF is set on the leading edge of ATN and after a delay through U11 B C D E ATN is enabled U32A and U43D to the remote unit as XATN through d
28. nual Appendix F Definition Remote Enable Ready for Data Remote Response Remote Source Remote System Controller Service Request Talker Talker Listener Talker Listener Controller GPIB Adapter Transistor Transistor Logic F 2 National Instruments Corporation User 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 Tide GPIB 100A User Manual Edition Date March 1990 Part Number 320063 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 Mail to Technical Publications National Instruments Corporation 6504 Bridge Point Parkway MS 53 02 Austin TX 78730 5039
29. ocal or remote state active They remain that way until one unit detects an IFC pulse from the System Controller which is on the same contiguous bus That unit enters the Local System Controller LSC state and causes the other unit to enter the Remote System Controller RSC state The IFC and Remote Enable REN signals are switched to flow from the local to the remote unit Next one unit detects the ATN signal from the Active Controller enters the Local Active Controller LAC state and places the other unit in the Remote Active Controller RAC state The ATN signal is switched to flow from local to remote side and the Service Request SRQ is switched to flow in the opposite direction Finally one unit detects the DAV from the Source Handshake function of the Talker or Active Controller That unit enters the Local Source LS state and places the other unit in the Remote Source RS state The DAV and Data DIO signals are switched to flow from local to remote side and the Not Ready for Data NRFD and Not Data Accepted NDAC signals are switched to flow from remote to local side As the source side for these three key signals IFC ATN and DAV change the local remote states of each extender and the directions of the other GPIB signals change accordingly Chapter 4 Theory of Operation contains a more thorough discussion of this National Instruments Corporation 3 1 GPIB 100A User Manual Configuration and Operation Chapter 3 Talker
30. otocopied reproduced or translated in whole or in part without the prior written consent of National Instruments Corporation Trademarks Product names listed are trademarks of their respective manufacturers Company names listed are trademarks or trade names of their respective companies FCC DOC Radio Frequency Interference Compliance This equipment generates and uses radio frequency energy and if not installed and used in strict accordance with the instructions in this manual may cause interference to radio and television reception This equipment has been tested and found to comply with 1 the limits for a Class A computing device in accordance with the specifications in Subpart J of Part 15 of U S Federal Communications Commission FCC Rules and 2 the limits for radio noise emissions from digital apparatus set out in the Radio Interference Regulations of the Canadian Department of Communication DOC These regulations are designed to provide reasonable protection against interference from the equipment to radio and television reception in commercial areas There is no guarantee that interference will not occur in a particular installation However the chances of interference are much less if the equipment is used according to this instruction manual If the equipment does cause interference to radio or television reception which can be determined by turning the equipment on and off one or more of the following suggestions may
31. ration Characteristics hao 1 3 1 22 Performance 1 4 1235 Operating Characteristics 1 4 14 Blectrival CharactensHes 1 5 1 5 Environmental Characteristics 1 5 1562 Physical 1 6 1 7 Components and Accessories 1 6 D 1 Cable Assembly Wire D 1 National Instruments Corporation ix GPIB 100A User Manual Chapter 1 Description of the GPIB 100A Introduction The high speed GPIB 100A Bus Extender Figure 1 1 is used in pairs with a special parallel data transmission cable to connect two separate GPIB or IEEE 488 bus systems in a functionally transparent manner GPIB 100A BUS EXTENDER ACTIVE CONTROLLER LOC REM e Figure 1 1 The Model GPIB 100A Bus Extender While the two bus systems are physically separate as shown in Figure 1 2 devices logically appear to be located on the same bus as shown in Figure 1 3 Thus with the GPIB 100A it is possible to overcome two configuration restrictions imposed by ANSI IEEE Standard 488 1978 namely Cable length limit of 20 m total per contiguous bus 2 m times the number of devices on the bus whichever is smaller e Electrical loading limit of 15 devices per contiguous bus Each GPIB 100A system extends the distance limit by 3
32. reduce or eliminate the problem e Operate the equipment and the receiver on different branches of your AC electrical system e Move the equipment away from the receiver with which it is interfering e Relocate the equipment with respect to the receiver e Reorient the receiver s antenna e Be sure that the equipment is plugged into a grounded outlet and that the grounding has not been defeated with a cheater plug If necessary consult National Instruments or an experienced radio television technician for additional suggestions The following booklet prepared by the FCC may also be helpful How to Identify and Resolve Radio TV Interference Problems This booklet is available from the U S Government Printing Office Washington DC 20402 Stock Number 004 000 00345 4 Preface Organization of the Manual This manual is divided into the following chapters Chapter 1 Description of the GPIB 100A contains a brief description of the GPIB 100A Bus Extender and how it is used This section also lists all components and accessories In addition it provides system configuration performance operating electrical environmental and physical specifications for the GPIB 100A Chapter 2 Installation contains instructions for configuring and connecting the GPIB 100A into your system at your operating voltage Chapter 3 Configuration and Operation describes how to configure and operate a GPIB 100A system Chapter 4 Theory of Operation
33. ress the unit drives the local Not Ready for Data NRFD signal passively false U42C and U41C After the Active Controller is identified and before the Source Handshake 15 identified the unit drives Not Data Accepted NDAC signals U42B and U41D true Thus the unit appears in a normal RFD NDAC state to the local GPIB which is awaiting the first data or command byte When DAV is received it is first delayed slightly by U23A and associated RCD network and enabled 025 to the LS FF Setting the FF causes the Local Source Handshake to wait until changes have propagated and any parallel poll completes fully The purpose of the DAV delay is to filter tail end unstable transitions from a fast rising edge DAV is further delayed through U23B C E F before being enabled at U25C by LS to be transmitted to the remote side as XDAV through driver U30B XDAV is received as RDAV on the remote side through U19D The signal sets the RS FF after all clearing conditions are removed U35B DAV is delayed 2 or more through U38C U48B and associated RCD network to ensure proper data setup time T1 on the remote side Once RS is set and the remote GPIB is ready for data U46A DAV is allowed to propagate 046 and 0360 to the remote GPIB through U47D U27C and GPIB transceiver and NRFD is transmitted to the other side through driver U30A XRFD Once the LS FF is set the propagation of NRFD from the remote side sets FF U36A
34. river U29B LAC enables the local unit to receive Service Request 5 from the remote unit through receiver U10B U32B and transceiver U2A XATN becomes RATN on the remote side and is received through U20B and propagated to the remote GPIB through transceiver U2C where the bus signal is received to clock RAC FF U22B When RAC is set drivers U8C D which transmit SRQ and parallel poll handshake signal BUS PP to the local unit are enabled that 1s toward the Active Controller Source Handshake Detection The Local Source LS handshake FF U45A is cleared via U33C on the following events e Before the Active Controller is identified TLC mode only e Whenever a change in the state of the local signal is caused by a pulse created via U38D U24A D and associated RC network e While or Data Valid DAV is received from the remote unit 0348 During a parallel poll 0460 The Remote Source RS handshake FF U36B is cleared via U33B on the following events e Before the Active Controller is identified TLC mode U33A only GPIB 100A User Manual 4 2 National Instruments Corporation Chapter 4 Theory Operation e Whenever a change in the state of the local signal is caused by a pulse created via U38E U24B C and associated RC network While ATN or DAV is received from the local side U34A D e During a parallel poll U38F and Before the LS FF is set and unless a parallel poll is in prog
35. ser Manual Table D 1 Cable Connector 5191 43 ree 5192 41 2 5195 47 6104 39 6195 18 5196 46 BUS SRQ BUS SRQ BUS REN BUS REN wo c o EH E 4A e E Cable Assembly Wire List Color Signature m wT 2101 ge NIN 5103 5107 5 fd Bd 2 5 55 els e zo wo OH OP ps CIC alg Zio me G o 25 Iz lt 9 Sle gle Qle lt 9 5 254 214 BIR 25 2 5 BIA as 35 38 32 15 BUSPP 17 BUSPP XFC 12 1 RIFC 35 11 22 5 RRFD RRFD 6 XRFD BUSDAC GRN BUSDAC 05 28 xEOI XEOI RDAV N o A 20 20 x 20 x gt gt VIO gt 212 21 lt lt lt ow A lt 9 o xp x 42 m 5 m RPON Qo N Nje N o m lt lt 9 Bl lt 91 Bix lt Vix 8 A 215 215 BIR 25 215 BIR 25 8 x X gt ivi 2 lt NI N NIN WIW Aje REO REOI 20 m ojo gt gt e lt lt gt N E XDAV RPON RPON XATN Connector P2B 44 43 34 48 47 36 39 42 18 46 40 35 37 28 30 32 14
36. sists of 16 signal lines and 8 ground return or shield drain lines The 16 signal lines are divided into three groups 8 data lines 3 handshake lines e Sinterface management lines GPIB 100A User Manual A 2 National Instruments Corporation Appendix A Operation of the GPIB Figure A 1 shows the arrangement of these signals on the GPIB cable connector DIO5 DIO6 DIO7 DIO8 REN GND TW PAIR W DAV GND TW PAIR W NRFD GND TW PAIR W NDAC GND TW PAIR W IFC GND TW PAIR W SRQ GND TW PAIR W ATN SIGNAL GROUND Figure A 1 GPIB Cable Connector Data Lines The eight data lines DIO1 through DIOS carry both data and command messages commands and most data use the 7 bit ASCII or ISO code set in which case the eighth bit DIOS is unused or used for parity Appendix E lists the GPIB command messages Handshake Lines Three lines asynchronously control the transfer of message bytes among devices The process is called a three wire interlocked handshake and it guarantees that message bytes on the data lines are sent and received without transmission error NRFD not ready for data NRFD indicates when a device is ready or not ready to receive a message byte The line is driven by all devices when receiving commands and by Listeners when receiving data messages National Instruments Corporation A 3 GPIB 100A User Manual Operation the GPIB Appendix A NDAC not data accepted ND
37. tension System Logical Configuration GPIB 100A User Manual 1 2 National Instruments Corporation Chapter 1 Description of the GPIB 100A GPIB 100A Specifications The following tables show the system configuration the performance operating electrical environmental and physical characteristics of the GPIB 100A as well as providing a list of available GPIB 100A components and accessories Table 1 1 System Configuration Characteristics Characteristic Specification loading per extension up to 14 additional devices multiple extensions permitted in any combination of star or linear pattern GPIB driver output no restrictions automatic conversion to 2 usec circuit and T1 timing T1 delay on remote side is built in of source device Note Tl is the data settling time DIO valid to DAV and varies according to the type of drivers and the system configuration used National Instruments Corporation 1 3 GPIB 100A User Manual Description of the GPIB 100A Chapter 1 Table 1 2 Performance Characteristics Characteristic Specification 250 to 135 kbytes sec approximately 4 usec per byte degraded at 10 5 nsec per meter of distance no limitation to device speeds when there are no on remote side of extension functionality transparent GPIB operation except for pulsed parallel polls interlocked maintained across the extension IEEE 488 handshake message grams not used IEEE 488 capability complete Source Handshake ident
38. ugh U10C When the local poll is over ATN or EOI unasserted FF U45B is cleared and U36D is set via U37B C and U26A Setting U36D latches National Instruments Corporation 4 3 GPIB 100A User Manual Theory of Operation Chapter 4 the remote poll response into register U16 Clearing U45B unasserts XEOI and XATN and after they propagate to the remote side BUS PP is also unasserted This causes FF U36D to be cleared as well terminating the parallel poll process and removing the NRFD condition of the local extender To recap FF U45B is set from the start of the local poll until the remote response is available and the local poll is over FF U36D is set from the time U45B is cleared until the remote poll handshake is over While either is set the local unit remains in an NRFD holdoff Data Direction Control The unit drives the GPIB data lines DIO1 to DIOS through transceivers U3 and U4 if there is a local parallel poll in progress U47B and 0264 or if the RS FF is set and a remote parallel poll 15 not in progress U47A and U27B Otherwise these lines are not driven The source for these data lines when they are driven is the remote unit through receivers U15 and U17 when Unbuffered PPR mode is selected Switch S1 position 3 open or when the RS FF is set and a remote parallel poll is not in progress U47A and U27B Otherwise the source is the Buffered PPR register U16 The unit drives the transmission data lines BUS DIO1 8 through
39. urpose Interface Bus Types of Messages Devices on the GPIB communicate by passing messages through the interface system There are two types of messages e Device dependent messages often called data or data messages contain device specific information such as programming instructions measurement results machine status and data files e Interface messages manage the bus itself They are usually called commands or command messages Interface messages perform such functions as initializing the bus addressing and unaddressing devices and setting devices for remote or local programming Note The term command as used here should not be confused with some device instructions which are also referred to as commands Such device specific instructions are actually data messages Talkers Listeners and Controllers There are three types of GPIB communicators A Talker sends data messages to one or more Listeners The Controller manages the flow of information on the GPIB by sending commands to all devices Devices can be Talkers Listeners and or Controllers A digital multimeter for example is a Talker and may also be a Listener A printer or plotter is usually only a Listener A computer on the GPIB often combines all three roles to manage the bus and communicate with other devices The GPIB is a bus like a typical computer bus except that the computer has its circuit cards interconnected via a backplane bus whereas the GPIB has standa
40. via receiver U19A U44C and U35A At this point the unit drives the NRFD and NDAC lines according to the levels sensed at the remote unit via U42C U41A D and GPIB transceiver UIC for NDAC Parallel Polling When the local unit detects and End Or Identify EOD asserted at the same time regardless of which occurs first FF U45D is set U26A U44E U48D and U43C This causes EOI to be transmitted to the remote side as XEOI through 0468 and driver U30C is also transmitted to the remote side as XATN through U43D and driver U29B XEOI and XATN remain asserted until the poll signals propagate to the remote unit and a response is returned even if the local signals become unasserted in the meantime To prevent the local side from further non poll activity NRFD is asserted via 46 U41C and transceiver U1D If the Buffered PPR mode is selected the contents of the PPR register U16 are routed through the A side of multiplexers 013 and 014 to the local GPIB The A side is selected whenever the local unit is not being polled from the other side 0278 and the RS FF is cleared 47 XEOI and XATN are received on the remote side as REOI and RATN through receivers U19B and U20B and propagated to the remote GPIB Two microseconds later a parallel poll handshake signal U27C U38A and associated RCD network is transmitted back to the local side through driver U8C as the signal BUS PP BUS PP is received at the local unit thro
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