USB GPIB Interface User`s manual
Contents
1. have access to the interface using DLL calls The new drivers for LabVIEW require D2XX You are advised to use these and the new version of LabVIEW drivers If you install VCP drivers another serial COM port is available There is no need to adjust speed and flow control settings to communicate to the interface The old drivers for LabVIEW require COM port therefore VCP drivers must be used in this case Note that only one type of drivers can be installed at a time If you have 64 bit Windows you can only install CDM drivers These are combined D2XX and VCP drivers Connection to the instruments Up to 15 GPIB devices can be connected to a GPIB bus This number includes the controller Devices can be connected in any configuration star bus or combined For correct operation at least one third of devices must be turned on Each device connected must have its own address on the bus LED indicator The interface has one green LED indicator at the side with USB connector This LED lights when the interface is initialised and ready for communication over GPIB bus D2XX or CDM drivers installation on Windows e Before connecting the interface to the PC check if you have USB drivers accessible e g unziped on your hard drive You can download them from our website e Connect the interface to the PC e Found New Hardware Wizard will appear on your screen Select No not at this time and click Next to continue e Inthe second window2. EOI will not be asserted with the last byte send Default 0 Note CR or LF is not added to the end of the stream even if Write Mode implies so Returns lt ACK gt or lt NAK gt if the number is invalid IBt lt TimeOutByte gt lt CR gt Sets byte timeout decimal value in increments of 32 768 ms This is the maximum time between two characters The timeout is also used for commands that transfer only one byte IBC IBc and IBB The timeout is accurate to one digit The timeout is reset to default when IBO command is issued and on power on If set to 0 the timeout is disabled Valid range is 2 65535 32 2 147 s Default 0 disabled Returns lt ACK gt or lt NAK gt if there is no number Note Valid range for firmware version 2 5 4 and lower is 2 255 32 8323 ms IBT lt TimeOutTot gt lt CR gt Sets total timeout for write and read decimal value in increments of 32 768 ms The timeout is accurate to one digit The timeout is reset to default when IBO command is issued and on power on If set to 0 the timeout is disabled Valid range is 2 65535 32 2 147 s Default 61 2 sec Returns lt ACK gt or lt NAK gt if there is no number IBf lt TimeoutFirst gt lt CR gt Sets timeout to transfer first byte on read and write in increments of 32 768 ms The timeout is accurate to one digit If set to 0 the timeout is disabled The timeout is reset to default when IBO command is issued and on power on If set to 0 the timeout
3. GPIB Read Reads data from the GPIB device at the VISA resource name If you do not specify an address the function does not perform addressing it attempt to read data The VI stops reading when EOI is detected EOS character is received or byte count byte are received Note that with EOS option the interface can read more characters but the VI will return only specified the other characters might get lost If firmware version is below 2 6 the same holds for byte count option byte count specifies the maximum number of bytes the function reads from the GPIB device If positive value is specified and firmware version is 2 6 or above maximum transfer rate will be about 30 lower mode specifies conditions other than reaching byte count for terminating the read 0 No EOS character The EOS termination mode is disabled 1 EOS character is CR Read terminated on EOI byte count or CR 2 EOS character is LF Read terminated on EOI byte count or LF xX Any other mode indicates the number decimal of the desired EOS character data contains the string read without the EOS character return count is the length of data If the read operation is terminated with EOS character or byte count the number of bytes actually read from the instrument might be higher These byte are lost Possible error codes returned 2 6 and 14 timeout ms VISA resource name byte count mode error in no error duplicate VISA resource name data return cou
4. and error passed to the output timeout ms specifies the maximum time a VI will use to send the data A VI will use the IBT command to set timeout if different from current setting Note that actual data transfer time will be limited to approx 100 ms lower value in order to compensate for addressing time This parameter applies to total timeout and is local to the VI To set Byte Timeout and First byte timeout use USB GPIB Set timeout function VISA resource name contains the address of the GPIB device with which a function communicates and the interface used for the communication To use our interface instrument s address should be prefixed with USB GPIB This prefixed should be used for all functions that communicate with our interface Instrument s address is a decimal string If you do not specify an address a function does not perform addressing before they attempt to read and write the string or commands duplicate VISA resource name is the same as VISA resource name input error out contains error information If error in indicates an error error out contains the same error information Otherwise it describes the error status that this VI produces Code numbers means the following 2 ENOL Write detected no Listeners Timeout when sending bus commands or data This is returned if error 0x08 No Listeners is returned from the interface 6 EABO I O operation aborted Serial port operation Error PC to interface protocol error A talker
5. is disabled Valid range is 2 65535 32 2 147 s Default 61 2 sec Returns lt ACK gt or lt NAK gt if there is no number IBN lt BytesToRead gt lt CR gt Sets number of bytes that IB command transfers Setting holds for all subsequent reads not just for the first one If EOI is not asserted with last byte transferred IB will return 0x07 instead of lt ACK gt Maximum transfer rate will be about 30 lower when this option is used Returns lt ACK gt Note This command is only implemented on firmware version 2 6 and above IBm lt ren gt lt CR gt Specifies if REN is asserted with IFC ren is decimal value Setting is reset to default when IBO command is issued and on power on 1 asserts REN 0 leaves REN unasserted Valid values of ren 0 1 Default 1 asserted Returns lt ACK gt or lt NAK gt if the number is invalid IBS lt CR gt Returns state of GPIB control lines The state is returned as is active zero as one byte No lt ACK gt is returned The bits are as follows 7 128 6 64 5 32 4 16 3 8 2 4 1 2 0 1 SRQ ATN EOI DAV NRFD NDAC IFC REN IBQ lt En gt lt CR gt Enables En 1 or disables En 0 interrupt on SRQ line SRQ line is monitored in idle mode If the interrupt is enabled and SRQ goes active lt ENQ gt character will be sent to the PC lt ENQ gt is also sent for subsequent inactive to active transitions If SRQ line is already active and the interrupt enable command is issued
6. select Install the software from a list or specific Advanced and click Next to continue e Then select Search for the best drivers in these locations If you are installing from a removable media e g CD ROM tick Search removable media floppy CD ROM If you are installing from a hard drive tick Include this location in the search and browse to the folder with drivers Click Next to continue e Information window should now appear Wait for the installation to complete e After the installation window will appear saying The wizard has finished installing the software for FTDI FT8U2XX device Click Finish to close the window Interface commands If you will be using LabVIEW drivers there is no need to read this chapter The commands described here are implemented in the driver Communication with the interface can be established from any program that provides serial communication or a programming language using DLL calls depending on installed USB drivers Commands for the interface begin with IB which is followed by a command code parameter and a carriage return CR Commands are case sensitive Data transmitting is an exception and does not require CR The interface has an on board FIFO and there is no need to wait for a command to end before sending next one Commands for GPIB communication will power on the interface and perform interface clear if powered off Commands IB lt CR gt Powers on the interface and performs int
7. with lt ESC gt On a timeout the interface normally returns 0x09 No Data Timeout operation is the same as for Bdata The Byte timeout is not enabled if the transmit buffer is full Transfer can be interrupted by sending lt ESC gt to the interface This character can only be detected when the interface is waiting for data i e not at full speed The feature is useful to implement End Of String EOS character recognition Returns binary data in BSC and lt ACK gt 0x07 0x03 or 0x09 IBB lt CR gt Starts reception of one byte Received byte is sent to the PC alone Byte timeout applies for this command This is useful for reading serial poll status byte If byte is not received the interface returns 0x00 instead of byte read Returns byte and lt ACK gt 0x03 or 0x09 IBl lt type gt lt CR gt Sends identification string to the PC All strings ends with lt CR gt lt LF gt 0 Type of the device the interface 1 Manufacturer of the device 2 Version number IBZ lt CR gt Performs interface clear by pulling IFC low for 100 us REN will be set according to setting Returns lt ACK gt IBO lt CR gt Powers off the interface and returns Write Mode timeout and REN setting to default state Returns No result code is returned IBe lt Write Mode gt lt CR gt Sets Write Mode decimal value The mode is reset to default when IBO command is issued and on power on 0 3 EOI will be asserted with the last byte send 4 7
8. 488 Connector 24 pin centronics socket Transfer rate Talk max 420 KBps Listen max 440 KBps General Dimensions LxWxH 66x66x28 mm Weight 85g Specifications for v1 Transfer rate Talk max 210 kBps Listen max 220 kBps General Dimensions LxWxH 123x70x30 mm Weight 106 g Other specifications are the same as the one for v2 Designed by University of Ljubljana Faculty of Electrical Engineering Tr a ka cesta 25 1000 Ljubljana Slovenia Laboratory of Photovoltaics and Optoelectronics http lpvo fe uni lj si http lpvo fe uni lj si gpib Dr Marko Topi Head of LPVO E mail marko topic at fe uni lj si Phone 386 1 4768 470 Dr Bo tjan Gla ar E mail bostjan glazar at fe uni lj si Phone 386 1 4768 723 Last update May 2010 Disclaimers FEE reserves the right to make changes to its products and or software at any time to improve design and or performance This product is provided as an assembled KIT that is without any warranty or guaranteed support FEE is not liable and does not provide free of charge repair or refund in case of malfunction To the extent not prohibited by law in no event will FEE be liable for any lost data revenue or profit or for special indirect consequential incidental or punitive damages regardless of the theory of liability including negligence arising out of or related to the use of or inability to use the product including any software even if F
9. EE has been advised of the possibility of such damages In no event will FEE liability exceed the amount paid by you for the product This product is not designed for use in life support appliances or systems where malfunction of this product can reasonably be expected to result in personal injury FEE customers using or selling this product for use in such applications do so at their own risk and agree to fully indemnify FEE for any damages resulting from such application Document revision history Rev 4 3 Date October 2010 CDM drivers added Rev 4 2 Date May 2010 New controller command described IBN New LabVIEW VIs described USB GPIB Write List vi USB GPIB Trigger List vi Rev 4 1 Date September 2009 Laboratory was renamed from Laboratory of Semiconductor Devices to Laboratory of Photovoltaics and Optoelectronics Rev 4 0 Date March 2006 D2XX drivers installation added D2XX LabVIEW drivers added Firmware upgraded with boot loader Specifications updated for version 2 0 of the interface Some spelling errors corrected Rev 3 1 Date December 2005 USB GPIB Trigger was added Rev 3 0 Date October 2005 IBdata IB lt CR gt IBB lt CR gt and timeout interface commands complemented for new timeout features Description of new interface commands IBS IBQ and IBf added ENQ return code added to the list LabVIEW drivers description updated VISA Descriptions of USB GPIB Read and USB GPIB Read S
10. ENQ is also sent Default value is disabled Returns lt ACK gt or lt NAK gt if the number is invalid Return codes One byte result code is sent after every command The exception is when USB goes to suspend state and when the interface is powered off In this case nothing is sent to the PC lt ACK gt 0x06 Command completed normally 0x07 EOI Not Asserted EOI was not asserted with the last byte transferred on read More bytes might be at the device output buffer Note This response is only possible on firmware version 2 6 and above lt NAK gt 0x15 Command is not recognised It can also be sent if the command gets too long lt ENQ gt 0x05 SRQ interrupt SRQ line transitioned from inactive to active state This is only possible during idle and if enabled 0x01 Not Ready Time out occurred before NRFD became false during talking 0x02 Not Accepted Time out occurred before byte was accepted NDAC became false during talking 0x03 Not DAV Released Time out occurred before DAV was released during listening 0x08 No Listeners Time out occurred before NRFD or NDAC became true 0x09 No Data Time out occurred before reception DAV true of a byte USB suspend operation When USB goes to suspend state current operation is aborted without result code and the interface is powered off It remains in that state till first received byte from the PC LabVIEW drivers for D2XX L
11. TB complemented New LabVIEW functions added USB GPIB Wait SRQ and USB GPIB Set timeout Firmware revision V2 4 0 added Rev 2 0 Date April 2005 Link to FTDI updated Description if IBdata and IB commands corrected according to new firmware timeouts Descriptions of other commands revised New commands support by firmware V2 3 added IBe IBt IBT IBm More detailed description of error codes returned added Some grammatical errors corrected
12. University of Ljubljana Faculty of Electrical Engineering Laboratory of Photovoltaics and Optoelectronics Be ee 24 Io ae USB GPIB Interface v2 User s manual Rev 4 3 October 2010 Introduction The interface communicates with PC through USB which is also used to power it On the other side GPIB IEEE 488 connector is provided to connect to the bus This enables control of instruments and other GPIB devices Maximum number of GPIB devices connected is 14 plus this interface Current version of firmware enables this device to be system controller only Multi controller and device operations are not supported at present Front matter The information presented in this document does not form part of any quotation or contract is believed to be accurate and reliable and may be changed without notice No liability will be accepted by the publisher for any consequence of its use Publication thereof does not convey nor imply any license under patent or other industrial or intellectual property rights Connection to the PC Universal Serial Bus USB is used for communication between the interface and the PC and to provide power USB version is 2 0 with Full speed supported The interface enumerates as a serial interface and drivers are requested There are two types of drivers Virtual Com Port VCP and D2XX drivers Both can be downloaded from FTDI s homepage http www ftdichip com With D2XX you
13. abVIEW drivers are designed as a collection of VIs USB GPIB Initialization USB GPIB Write USB GPIB Write List USB GPIB Read USB GPIB Clear USB GPIB Read STB USB GPIB Request Wait USB GPIB Wait SRQ USB GPIB Set timeout USB GPIB Trigger USB GPIB Trigger List and USB GPIB Close In order to use the interface in LabVIEW all functions that communicate with instruments should be replaced with ours Our functions will pass control to LabVIEW VISA functions if VISA resource name does not begin with USB GPIB This enables creation of only one program for both types of GPIB interfaces All functions except Initialization Close and Wait SRQ perform addressing and un addressing after completion if an address is given and re addressing enabled at initialisation Execution is divided into steps and if an error occurs at one step execution is stopped and proper error code returned Each step is composed of sending interface command and waiting for a response All functions send one command at a time and wait for acknowledge LabVIEW drivers are designed in LabVIEW 6 0 For LabVIEW 5 0 drivers contact us Drivers for older versions of LabVIEW are not available To use these functions virtual D2XX drivers should be installed for the interface Common parameters and returns to all functions error in describes error conditions that occur before a VI runs The default input of this cluster is no error If there is an error wired to a VI VI will be skipped
14. e read or write to the next This can be disabled in order to speed up communication Address is not retained when multiple addresses are used Trigger List and Write List The default is TRUE If assert REN with IFC is TRUE the function asserts the Remote Enable line The default is TRUE Possible error codes returned 6 7 require re addressing T assert REN with IFC T i VISA resource name 5 duplicate VISA resource name error in no error error out USB GPIB Initialization vi USB GPIB Write Writes data to the GPIB device identified by VISA resource name The VI performs addressing if an address is given and re addressing is enabled or the address is different from current data is the data the function writes to the GPIB device Mode indicates how to terminate the GPIB Write The VI will use the IBe command to set EOI mode if different from current setting Default is 0 Send EOI with the last character of the string Append CR to the string and send EOI with CR Append LF to the string and send EOI with LF Append CR LF to the string and send EOI with LF Append CR to the string but do not send EOI Append LF to the string but do not send EOI Append CR LF to the string but do not send EOI Do not send EOI Possible error codes returned 2 6 and 14 NOOR WDM O timeout ms VISA resource name data Mode error in no error duplicate VISA resource name error out USB GPIB Write vi USB
15. erface clear The green LED indicator will turn on Returns lt ACK gt IBCx lt CR gt and IBcx lt CR gt Both send byte x as a bus command with and without releasing ATN line respectively The later can be used to send multi byte bus commands Byte timeout applies for this command Returns lt ACK gt 0x01 0x02 or 0x08 IBdata Sends binary data in BSC format Data should begin with lt DLE gt lt STX gt and end with lt DLE gt lt ETXs gt If lt DLE gt is to be transferred it is followed by another lt DLE gt EOI will be asserted with the last byte transferred if enabled If timeout occurs during operation error code will be immediately sent but the command should still be concluded with lt DLE gt lt ETXs gt If lt DLE gt lt ACK gt is encountered in a stream the interface will respond with lt ACK gt This can be used to know how much data was already sent i e not waiting in buffer Total timeout starts when the command is initiated If this timeout occurs the transfer of current byte is finished and error returned normally 0x01 Not Ready First byte must be transferred before First byte timeout occurs After the first byte time between byte is limited with Byte timeout Returns lt ACK gt 0x01 0x02 or 0x08 IB lt CR gt Starts receiving binary data in BSC format Control bytes will be sent to the PC even if there is no data available Reception is finished when EOI is detected a timeout occurs or interrupted
16. es not clear the SRQ flag SRQ is true if SRQ occurred within the timeout Possible error codes returned 6 and 14 timeout ms VISA Resource Name duplicate YISA resource name SRQ error in no error a error out USB GPIB WaitSRQ vi USB GPIB Trigger Triggers a single device using GET bus command If you specify an address the function sends trigger to that address If you do not specify an address the function does not perform addressing before it sends trigger It assumes you have sent this commands another way Possible error codes returned 2 6 and 14 VISA resource name duplicate VISA resource name error in no error error out USB GPIB Trigger i USB GPIB Set timeout Sets timeouts of the GPIB interface The timeouts are also written to global variables Total timeout is maximum duration of a GPIB operation If set to 1 the timeout will not change Use 0 to disable the timeout The defaults value is 10 000 ms First byte timeout is maximum duration between the start of a transfer command and the first byte transferred If set to 1 the timeout will not change Use 0 to disable the timeout The defaults value is 10 000 ms Byte timeout is maximum duration between successive two bytes during write or read operation This timeout is also used for commands that transfer only one byte IBC IBc and IBB If set to 1 the timeout will not change Use 0 to disable timeout The defaults value is 1 000 ms Pre
17. has no data to send 0x09 No Data on read A listener is not ready for data 0x01 Not Ready 7 ENEB Non existent board There is an error opening the serial port 14 EBUS GPIB bus error Time out occurred before NRFD became false during talking 0x01 Time out occurred before byte was accepted NDAC became false during talking 0x02 Time out occurred before reception DAV true of a byte This code is applicable to both bus commands and data String returned in error out has the following format lt name of VI gt lt description of error gt Description is added to extend error codes T O T O error occurred when communicating with serial port Ctrl Returned if there is a PC to interface protocol error Not Rdy Returned if 0x01 Not Ready response received from the interface Not Acc Returned if 0x02 Not Accepted response received from the interface Not DAV Rel Returned if 0x03 Not DAV Released response received from the interface No Lstn Returned if 0x08 No Listeners response received from the interface No data Returned if 0x09 No Data response received from the interface Vis USB GPIB Initialization Opens serial port sets REN state powers on the interface and performs interface clear using command IB lt CRs It also sets global variables If require re addressing is TRUE the function addresses the device before every read or write If FALSE the device must be able to retain addressing from on
18. irst byte timeout was limited to only 255 All timeouts including byte timeout are now 16 bits maximum 65535 Rev V2 5 3 Feb 2008 Waiting for DLE ETX after error updated for 16 MHz clock correct FTDI cycles Sending NAK immediately after NotDAVrel error omitted Rev V2 5 2 Oct 2007 T1 delay is now corrected 1100 ns Rev V2 5 1 Nov 2006 T1 delay updated to standard Rev V2 5 0 March 2006 nop instruction added when reading FTDI to correctly support 16 MHz clock Access time for FTDI is now 1 5 cycle 100 ns at 16 MHz Added debug commands to check lines as device Corrected bug in converting received 0x0A to 0x0D in conjunction with debug commands Rev V2 4 0 October 2005 Each timeout can now be disabled IBf IBQ and IBS commands added Handshake timeout not used any more for write while waiting for listener Reading of one byte IBB corrected to return null in case of timeout Rev V2 3 0 March 2005 Interruption of data received corrected Corrected bug with releasing REN on timeout Added total timeout Added option for Write Mode disabling EOD Added ACK during write Compacted code in SendBinData function Debug commands are now standard repertory Operation with variable flags corrected Specifications for v2 USB Power 5V 320 mA Bus powered Standard 2 0 1 1 compatible Speed Full speed 12 Mbps Connector B Receptacle GPIB Standard TEEE
19. nt error out USB GPIB Read vi USB GPIB Clear Sends either SDC Selected Device Clear or DCL Device Clear If you specify an address in address string the function sends SDC to that address If address string is unwired the function sends DCL Possible error codes returned 2 6 and 14 VISA resource name duplicate VISA resource name error in no error error out USB GPIB Clear vi USB GPIB Read STB Serial polls a single device to get its status byte serial poll response is the status byte of the device at address string You can learn how to interpret this byte from the documentation supplied with your device 1 is returned if the byte can not be read Possible error codes returned 2 6 and 14 VISA resource name duplicate VISA resource name seriall poll response error out error in no error USB GPIB Read STB vi USB GPIB Request Wait Waits for Service Request using USB GPIB Read STB and monitoring bit 6 of the status byte Status byte is serial poll response from USB GPIB Read STB Possible error code returned 6 timeout ms VISA resource name duplicate ISA resource name Status byte error out no error error in no error USB GPIB Request Wait vi Waits For Service Request using serial poll USB GPIB Wait SRQ Waits for SRQ line to be asserted using interrupt If the line is active when the VI is called it immediately returns Note The function is passive to the bus and do
20. uplicate VISA resource nam error out error in no error USB GPIB Trigger List i LabVIEW drivers for VCP These drivers communicate with the interface through Virtual Serial Port VCP To use this functions virtual COM port should be installed as a FTDI driver Functions access serial port through VISA library These VIs are very similar to LabVIEW drivers for D2XX with following exceptions e address string is used instead of VISA resource name The string only contains decimal address of the instrument e USB GPIB VISA used for USB GPIB Initialization and USB GPIB Close is a VISA reference to serial port the interface is connected to This parameter is global for all functions Note These drivers are not maintained Uses are encouraged to use D2XX drivers Firmware upgrades Firmware of the microcontroller can be upgraded to support other GPIB features and options Check our web page for firmware updates If there is no need you should not update the firmware as an error during the upgrade such as power failure could cause the interface to malfunction and force you to send the interface to service Firmware revision history Rev V2 6 Apr 2010 Added command IBN end read by byte count If read operation is terminated because of byte count IBN not EOI 0x07 will be returned instead of lt ACK gt 0x06 Rev V2 5 4 Oct 2009 Byte timeout couldn t be disabled This is now fixed Maximum value for F
21. vious total timeout is the previous total timeout period for all GPIB Functions Previous first byte timeout is the previous first byte timeout period for all GPIB Functions Previous byte timeout is the previous byte timeout period for all GPIB Functions Note There should be at least one valid timeout always enabled otherwise the interface might hang up Possible error codes returned 14 interface error Previous First byte timeout Previous total timeout Previous byte timeout error out First byte timeout Total timeout Byte timeout error in no error USB GPIB Set timeout yvi USB GPIB Close Turns off GPIB interface and closes serial port Possible error codes returned 2 6 and 14 VISA resource name error in no error error out USB GPIB Close i USB GPIB Write List Writes data to multiple GPIB devices identified by VISA resource name array with a single transfer All devices will receive data at exactly the same time Other parameters and returns are the same as for USB GPIB Write Note This VI is included in version 3 2 and above timeout ms VISA resource name Array data Mode error in no error USB GPIB Write List vi ee duplicate YISA resource nam error out USB GPIB Trigger List Triggers multiple single device using GET bus command Other parameters and returns are the same as for USB GPIB Write Note This VI is included in version 3 2 and above VISA resource name Array d
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