USB TC-08 Help
Contents
1. Note The CJC is always enabled automatically if a thermocouple is being used When no channels are active as thermocouples the CJC can be optionally enabled or disabled usb_tc08_run long usb_tc08_run short handle long interval This routine starts the unit running with a sampling interval specified in milliseconds This routine should be called after usb _tc08 set_channel has been called Arguments handle Specifies the USB TC 08 unit interval Specifies the requested sampling period You can use usb tc08 get minimum interval ms to obtain the smallest sampling period permitted with the current setup Returns 0 Use usb tc08 get last error Interval Actual interval allowed by the driver 2005 Pico Technology Limited All rights reserved USBTC08044 2 25 USB TC 08 Help 3 3 3 3 usb_tc08_get_single short usb_tc08_get_single short handle float temp short overflow_flags short units You must set up the channels before calling this function You must not have put the unit into Streaming mode with usb tc08 run as this will cause usb_tc08_get_single to fail The function will convert all readings on demand For more details and an example see the Get Single mode section Arguments handle Specifies the USB TC 08 unit temp Pointer to an array of length 9 There are 9 channels on the USB TC 08 8 cold junction and the readin2. USB TC 08 Temperature Logger User guide 2005 Pico Technology Limited All rights reserved USBTC08044 2 I USB TC 08 Help Table of Contents e Tt d e Te ONE 2 d Overview us beasEg e ce ieee eects rener i rar R a T E RA REE aaa Ea a R NE RRR E 2 2 Installing the driver csssessssssssssseeeeessseneseseeeneneneseeenenereeeeeeneees 2 3 Connecting the USB TC 08 essssnnnnnnnrrnrrnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnne 2 4 Legal information EEN 5 5 Safety warning E EEEEEEEEERREEEEEEEEEEEEEEERREEEEEEEEEEEEEEERREEEESEEEEEREEEERREEEEER KEEN 6 6 Company details sss s rrnsssrssnnnannnnnrnennnnannnnnnnennnnnnnnnnnnennnnnnnnnnnnennnnnnnnn 7 2 Prod ct information secesccccerceccaceccsccccarnscecmireccecrerceceetertecerrecnerernernecermeceetiecins 8 1 Specifications EEN 8 2 How a thermocouple works s sssssssssssssssnsunsnnsunnnnnnnnnnnnnnnnnnnnnnnnnnnnnune 9 3 Technical reference vec cisnccicccnicncncnicaicacneadadatcdedicededecccnccccccccccececececicncncncncaemeaeatce 10 i Introduction isn a a a a a 10 2 Modes of operation EEN 10 3 Driver routines ssusgess ee SSSNESASSEEN EE ERNEER EENS EES REENEN EEN EEEA EES EEN 15 4 Programming eeEEEEEEEEEREEEEEEEREEEEEEEREEEEEEEEREEEEEEEREEEEEEEEEEEEEEEEREEEEEEEREEEE EEN 34 5 Troubleshooting 1 rrrsnnnnnrnnnnsrnnnnnnnnnnnnennnnnnnnnnnnennnnnnnnnnnnennnnnnne 36 6 Glossary s ssssssessssnssenssnnsennnonnnonnson
3. More information on choosing and using thermocouples can be found at this page on our website USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 10 3 3 1 3 2 3 2 1 3 2 2 Technical reference Introduction The USB TC 08 is supplied with driver routines that you can build into your own programs The USB TC 08 driver supports the following versions of the Windows operating system 98SE ME 2000 and XP Once you have installed the software the DRIVERS directory will contain the drivers anda selection of examples of how to use the drivers The driver is supplied as a Windows DLL The DLL uses the C stdcal1 calling convention and can be used with C Delphi and Visual Basic programs It can also be used with programs like Microsoft Excel where the macro language is a form of Visual Basic Modes of operation Introduction The USB TC 08 is designed for three specific modes of operation to suit a variety of applications The following modes are supported Streaming mode Get Single mode Legacy mode Streaming mode Streaming mode is an operational mode in which the USB TC 08 unit samples data and returns it to the computer in an unbroken sequence using the onboard clock to ensure accurate timing The unit can buffer up to two sets of readings at once To avoid loss of readings make sure that another application on the PC including the one you are writing
4. lt c printf nChannel d overflowed c else no overflow printf nChannel d Sf c value_array c if i lt 9 while 60000 gt GetTickCount last_time 60000ms 1 minute Sleep 100 let other applications run last_time GetTickCount 2005 Pico Technology Limited All rights reserved USBTC08044 2 13 USB TC 08 Help 3 2 4 Legacy mode Legacy mode is designed to aid developers who have already written code for the serial version of the TC 08 and are not yet ready to rewrite their code for the Streaming or Get Single modes available with the USB version The legacy support is going to be phased out and will eventually be removed from the driver altogether If you want full support in the future use the Streaming or Get Single modes To allow code to be easily developed for both the serial version and the USB version of the TC 08 all the function names have been changed The usb tc08 legacy set channel function no longer supports offset and gain this is now stored only as calibration information in the unit itself The legacy routines will be familiar if you previously used the serial TC 08 but the following changes should be made to convert legacy applications Reference the new Header file Reference the new Library file Place the new DLL in the directory of the application Set the mains frequency Run and stop the unit
5. usb_tc08_get_temp_deskew 15 usb_tc08_get_unit_info 15 20 usb_tc08_legacy_get_cold_junction 15 32 usb_tc08_legacy_get_cycle 15 33 usb_tc08_legacy_get_driver_version 15 32 usb_tc08_legacy_get_temp 15 31 usb_tc08_legacy_get_version 15 32 usb_tc08_legacy_run 15 29 usb_tc08_legacy_set_channel 15 30 usb_tc08_open_unit 15 16 usb_tc08_open_unit_async 15 17 usb_tc08_open_unit_progress 15 18 usb_tc08_run 15 24 usb_tc08_set_channel 15 24 usb_tc08_set_mains 15 19 usb_tc08_stop 15 19 usb_tc08_temp_deskew 28 22 36 35 G Get single mode H Hot junction 9 HP Vee 35 Impedance 8 Installation 2 L LabVIEW 35 Legacy mode M Modes of operation Get single 10 Legacy 10 13 Streaming 10 MS Excel 35 P Programming C 34 C Delphi 34 HP Vee 35 LabVIEW 35 Visual Basic Q QNaN R Repairs 6 Resolution 8 10 11 10 10 34 34 35 26 28 40 2005 Pico Technology Limited All rights reserved 41 USB TC 08 Help S Safety 6 Specification 8 Streaming mode 10 T Thermocouple 9 Troubleshooting 36 U usb_tc08_close_unit 15 19 usb_tc08_get_formatted_info 15 21 usb_tc08_get_last_error 15 22 usb_tc0O8_get_minimum_interval_ms 15 20 usb_tcO8_get_single 15 25 usb_tcO8_get_temp 15 26 usb_tcO8_get_temp_deskew 15 usb_tc0O8_get_unit_info 15 20 usb_tc08_legacy_get_cold_junction 15 32 usb_tcO8_legacy_get_cycle 15 33 usb_tc08_legacy_get
6. All rights reserved Technical reference 34 3 4 3 4 1 3 4 2 3 4 3 Programming Introduction We supply examples for the following programming languages C and C Delphi Excel LabVIEW Visual Basic HP Vee C and C C The C example program is a generic Windows application it does not use Borland AppExpert or Microsoft AppWizard To compile the program create a new project containing the following files usb_tc08tes c usb_tc08tes rc either usbtc08bc 1ib Borland 32 bit applications or usbtc08 lib Microsoft Visual C 32 bit applications The following files must be in the same directory usb_tc08tes rch usbtc08 h usb_tc0832 d11 All 32 bit applications C C programs can access all versions of the driver If usbtc08 h is included in a C program the PREF1 macro expands to extern C this disables name mangling or name decoration and enables C routines to make calls to the driver routines using C headers Delphi The WIN sub directory contains a simple program usbtc08 dpr which opens the drivers and reads temperatures from the three channels You will need the following files to build a complete program usbtcO8fm dfm usbtc08fm pas usbtc08 inc The file USBTCO8 inc contains procedure prototypes for the driver routines you can include this file in your application This example has been tested with Delphi versions 1 2 and 3 2005 Pico Technology Limited A
7. The string is separated into the following elements each appearing on a different line driver version hardware version variant info serial number calibration date Arguments handle Specifies the USB TC 08 unit unit_info A string where the unit info is to be placed string_length Length of the string to be copied Should be at least 256 USBTC08_MAX_INFO_CHARS characters long Returns 0 Too many bytes to copy will copy as many full lines as possible 1 Routine was successful USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 22 3 3 2 10 usb_tcO8_get_last_error short usb_tc0O8_get_last_error short handle This routine returns the last error for the unit specified by of a handle the function returns the error associated with usb tc08 open unit or usb US open unit async handle If zero is passed instead the last call to Note If an invalid handle is passed to a function the function will fail The error code however cannot be associated with a unit so usb_tc08_get_last_error will not retain an error code in this instance usb_tc08_get_last_error will also fail if the invalid handle is passed to it The error codes also found in the C header file are as follows User Developer error codes Error Error code Further information 0 USBTCO8_ERROR_OK No error occurred 1 USBTCO8_ERRO
8. connected directly to the ground of your computer through the interconnecting cable provided This is done in order to minimise interference If the PC especially laptop is not grounded reading stability cannot be guaranteed and it may be necessary to manually ground the equipment As with most oscilloscopes and data loggers you should take care to avoid connecting the inputs of the product to anything which may be at a hazardous voltage If in doubt use a meter to check that there is no hazardous AC or DC voltage Failure to check may cause damage to the product and or computer and could cause injury to yourself or others Take great care when measuring temperatures near mains equipment If a sensor is accidentally connected to mains voltages you risk damage to the converter or your computer and your computer chassis may become live You should assume that the product does not have a protective safety earth Incorrect configuration or use of the device to measure voltages outside the maximum input range can be hazardous Repairs The unit contains no user serviceable parts repair or calibration of the unit requires specialised test equipment and must be performed by Pico Technology Limited or their authorised distributors 2005 Pico Technology Limited All rights reserved USBTC08044 2 7 USB TC 08 Help 1 6 Company details Address Pico Technology Limited The Mill House Cambridge Street St Neots Cam
9. does not prevent the driver from collecting readings for more than three sampling intervals To allow the driver to sample continuously call the Windows Sleep function in any sampling loops See example below to make sure that your application does not use too much processor time Hint Try not to use a Sleep call for less than 50 100 milliseconds e g Sleep 50 or Sleep 100 If you are programming a Windows GUI application a good alternative to sampling loops is the WM_TIMER message 2005 Pico Technology Limited All rights reserved USBTC08044 2 11 USB TC 08 Help 3 2 3 Example The following code is a fragment of a C application demonstrating how to use Streaming mode with the USB TC 08 driver Setting up and running the unit in Streaming mode if usb_tc08 set _mains handle 0 use 50Hz mains noise rejection for channel 0 channel lt 9 channel t set each channel up as a type K thermocouple channel 0 is the cold junction and will be enabled by setting the third argument to anything other than usb_tc08_set_channel handle channel K U U find out how fast the unit can sample in its current setup state minimum_interval usb _tc08_ get _minimum_interval_ ms handle usb_tc08 run handle minimum_interval sample as fast as possible not required just illustrates that the application can be idle while the driver coll
10. from iron and constantan They measure temperatures in the range 210 to 1200 C The main application is with old equipment that can not accept the more modern thermocouple J types should not be used above 760 C as an abrupt magnetic transformation will cause permanent decalibration Type K thermocouple Type K thermocouples are low cost general purpose thermocouples made from chromel and alumel operating in the 270 C to 1370 C temperature range Sensitivity is approx 41 uV C Type N thermocouple Type N thermocouples are made from nicrosil and nisil The high stability and resistance to high temperature oxidation of these thermocouples make them suitable for measuring high temperatures They are less expensive than platinum types B R and S and were designed to be an improved type K Type R thermocouple Type R thermocouples are made from platinum and rhodium and are suitable for high temperature measurements of up to 1760 C Low sensitivity 10 uV C and high cost make them unsuitable for general purpose use Type S thermocouple Type S thermocouples are made from platinum and rhodium and are suitable for high temperature measurements of up to 1760 C Low sensitivity 10 uV vC and high cost make these thermocouples unsuitable for general purpose use Due to their high stability type S thermocouples are used as the standard of calibration for the melting point of gold Type T thermocouple Type T thermocouples are mad
11. know which one to select from the list 7 Click the OK button The following dialog box appears USBTC08044 2 2005 Pico Technology Limited All rights reserved Introduction 4 TCO8 Channels X Serial Cold junction unused Edit Channel 2 unused Channel 3 unused Channel 4 unused Channel 5 unused Help Channel 6 unused Channel 7 unused Channel 8 unused Hii Disable Mains Frequency 50Hz D 8 In the TC 08 Channels window double click on Channel 1 unused The Edit TC 08 Channel dialog box appears Edit TCO8 Channel X O Semmmmmm Thermocouple Type K pep IT Filter Enable Filter Factor T Cancel Help Options 9 From the Thermocouple drop down list select the type of thermocouple you are using and click the OK button The TC 08 Channels dialog box reappears 10 Click the OK button Channel 1 should now appear in the monitor window with the current temperature reading Fie Settings View Help B S E a m e Awaiting data filename Use File New data Channel 1 2005 Pico Technology Limited All rights reserved USBTC08044 2 5 USB TC 08 Help 1 4 Legal information The material contained in this release is licensed not sold Pico Technology Limited grants a licence to the person who installs this software subject to the conditions listed below Access The licensee agrees to allow access to this software only to persons who have be
12. meanings Find a routine which fails with one of these error codes Dn Errors in this category are user dependent and developers should make sure that their application provides suitable error messages for users to read in the event of an error occurring 2005 Pico Technology Limited All rights reserved USBTC08044 2 37 USB TC 08 Help 3 6 Glossary CJC A method of compensating for ambient temperature variations in thermocouple circuits Cold junction compensation See CJC Common mode range The voltage range relative to the ground of the data logger within which both inputs of a differential measurement must lie in order to achieve an accurate measurement DLL Dynamic Link Library Files with this file extension contain a collection of Windows functions designed to perform a specific class of operations Input impedance The resistance measured between the input terminals of a circuit NFR Noise Free Resolution The effective number of bits of resolution that can be considered noise free Overvoltage protection The maximum input voltage that can be applied without damaging the unit QNaN Quiet Not a Number In the context of the USB TC 08 QNaNs are numbers created artificially to fill in gaps in sampling These gaps are interruptions caused by lack of available PC or laptop processor time normally caused by too many applications being open simultaneously QNaNs are defined in the IEEE 754 1985
13. on your computer using the cable provided Next connect a thermocouple to one of the thermocouple input connectors To complete the installation select the USB TC 08 unit and thermocouple type in PicoLog as follows 1 Start up PicoLog Recorder 2 Select New Settings from the File menu The Recording dialog box appears Recording ES Recording method Real time continuous Me Action at end of run Stop Restart delay H Minutes T Use multiple converters Cancel Help 2005 Pico Technology Limited All rights reserved USBTC08044 2 3 USB TC 08 Help 3 Click the OK button The Sampling Rate dialog box appears Sampling Rate ES Sampling interval fi Seconds DI Maximum number of samples 500 Cancel Readi 4 Click the OK button The Converter details dialog box appears Converter details X Port E Cancel USB Devices Help Device an Serial Converter type Status USB enumeration progress Refresh 5 Select USB TC 08 from the drop down list of converters The device name and serial number should appear in the USB Devices pane and the USB enumeration progress bar gradually expands to 100 If the progress bar does not start moving disconnect and reconnect the USB TC 08 then click Refresh 6 In the USB Devices pane select the USB TC 08 If you are using more than one USB TC 08 check the serial number on the bottom of the device so that you
14. operating the USB TC 08 in legacy mode having called usb tc08 legacy run 2005 Pico Technology Limited All rights reserved USBTC08044 2 31 USB TC 08 Help 3 3 4 3 usb_tc08_legacy_get_temp short usb_tc08_legacy_get_temp long temp short handle short channel short filtered Once you open the driver and define some channels you can call the usb tc08 legacy run routine The driver will then constantly take readings from the USB TC 08 Temperatures are returned in hundredths of a degree Celsius and voltages are returned in microvolts Arguments channel Specifies from which channel to read temperature Should be 0 for CJC 1 for Channel 1 2 for Channel 2 and so on temp Pointer to a location where readings are to be placed Each reading should be compared with 2147483647L or LONG MAX include limits h to check for overflows An overflow occurs when the input signal is higher than the measuring range of the USB TC 08 filtered Specifies whether or not to filter the data The readings are median filtered if set to 1 0 causes the unfiltered temperature to be stored in temp The filter has a depth defined by the filter factor set during a usb legacy set channel call Returns 0 Use usb tc08 get last error 1 Temperature retrieval successful Note Do not call this function unless you are operating the USB TC 08 in legacy mode having called u
15. sample from a single channel at a rate of 10 samples per second The absolute minimum sampling interval with all 8 channels and the cold junction enabled is 900 ms You must set up all the channels that you wish to use before calling this routine usb_tc08_get_unit_info short usb_tc08_get_unit_info short handle USBTCO8_INFO info This routine gets the unit information and copies it to the USBTC08_INFO structure declared in the usbtc08 h header file If you pass zero to the function as the handle only the driver version member will be valid but the function will return 1 success Arguments handle Specifies the TC 08 unit info A pointer to a structure containing unit information Returns 0 Use usb tc08 get last error 1 Routine was successful You must assign the correct value to the size field of your USBTC08_INFO structure before calling this routine For example in C if devinfo is your structure use this code devinfo size sizeof USBTC08_INFO usb_tc08_get_unit_info hTC08 amp devinfo 2005 Pico Technology Limited All rights reserved USBTC08044 2 21 USB TC 08 Help 3 3 2 9 usb_tcO8_get_formatted_info short usb_get_formatted_info short handle char unit_info short string_length This function is similar to the usb get unit info routine but the unit information is returned in the form of a formatted character string
16. to 1370 C Type N 270 C to 1300 C 270 C to 1300 C Type R 50 C to 1760 C 50 C to 1760 C Type S 50 C to 1760 C 50 C to 1760 C Type T 270 C to 400 C 270 C to 400 C 2005 Pico Technology Limited All rights reserved USBTC08044 2 9 USB TC 08 Help 2 2 How a thermocouple works A discovery by T J Seebeck almost 150 years ago opened the way for modern thermoelectric circuitry In 1831 Seebeck discovered that an electric current flows in a closed circuit of two dissimilar metals when one of the two junctions is heated with respect to the other In such a thermocouple circuit the current continues to flow as long as the two junctions are at different temperatures The magnitude and direction of the current is a function of the temperature difference between the junctions and of the thermal properties of the metals used in the circuit This phenomenon is known as the Seebeck Effect The conductors can be made of any two dissimilar metals and when the hot junction is heated the current flow can be observed If the positions of the hot and cold junctions are reversed current flows in the opposite direction In fact a thermocouple circuit actually generates a measurable low voltage output that is almost directly proportional to the temperature difference between the hot junction and the cold junction A change in this temperature difference produces some net change in the voltage Note
17. 3 2 5 usb_tcO8_stop short usb tc08_ stop short handle This routine stops the unit from running Arguments handle Specifies the USB TC 08 unit Returns 0 Invalid parameter 1 Unit stopped streaming successfully 3 3 2 6 usb_tcO8_set_mains short usb_tc08_set_mains short handle short sixty_hertz This routine sets the USB TC 08 to reject either 50 or 60 Hz Arguments handle Specifies the USB TC 08 unit sixty hertz Specifies whether to reject 50Hz or 60Hz If set to 1 the unit will reject 60Hz if set to 0 the unit will reject 50Hz Returns Use usb tc08 get last error Mains rejection set correctly Note If the rejection is not set correctly the unit will be more susceptible to mains interference USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 20 3 3 2 7 3 3 2 8 usb_tc0O8_get_minimum_interval_ms long usb_tc08_get_minimum_interval_ms short handle This routine returns the minimum sampling interval or fastest millisecond interval that the unit can achieve in its current configuration The configuration is defined by calling usb tc08 set channel Arguments handle Specifies the USB TC 08 unit Returns 0 Use usb_tc08_get_last_error Minimum Minimum sampling interval for current setup in Interval milliseconds Note The USB TC 08 can
18. ISO standard and are indeterminate meaning no two QNaNs have the same value In C C the int _isnan double function in the lt float h gt header can be used to identify QNaN float representations cast to a double first QNaNs will not cause an error if arithmetic operations are performed on them however the results will remain indeterminate Resolution A value in bits related to the number of increments of an analog input signal that can be detected by a digital measurement system A high resolution measurement system detects smaller signal increments than a low resolution measurement system USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 38 Thermocouple A device consisting of two dissimilar metals joined together The thermoelectric voltage developed between the two junctions is proportional to the temperature difference between the junctions Type B thermocouple Type B thermocouples are made from platinum and rhodium and are suitable for high temperature measurements of up to 1820 C Unusually due to the shape of their temperature voltage curve type B thermocouples give the same output at 0 C as at 42 C Type E thermocouple Type E thermocouples are made from chromel and constantan They have a high output 68 uV C making them well suited to low temperature cryogenic use They are non magnetic Type J thermocouple Type J thermocouples are made
19. R_OS_NOT_SUPPORTED Need to use Windows 98 SE or later or Windows 2000 or later 2 USBTC08_ERROR_NO_CHANNELS_SET A call to usb tc08 set channel is required 3 USBTCO08_ERROR_INVALID_ PARAMETER One or more of the function arguments were invalid 4 USBTCO8_ERROR_VARIANT_NOT_SUPPORTE D The hardware version is not Supported Download the latest driver gt USBTCO08_ERROR_INCORRECT_MODE An incompatible mix of legacy and non legacy functions was called or usb tc08 get single was Called while in streaming mode 6 USBTCO8_ERROR_ENUMERATION_INCOMPL ETE usb tc08 open unit async paci called again while a b ackground enumeration was already in progress Note For more details on error codes see troubleshooting 2005 Pico Technology Limited All rights reserved USBTC08044 2 23 USB TC 08 Help Reserved Pico error codes Error code Error Further information j USBTC08_ERROR_NOT_RESPONDING Cannot get a reply back from a USB TC 08 unit 8 USBTC08 ERROR_FW _ FAIL Unable to download firmware 9 USBTC08 ERROR_CONFIG_FAIL Missing or corrupted EEPROM 10 USBTC08 ERROR NOT FOUND Cannot find enumerated device 11 USBTC08 ERROR_THREAD FAIL A threading function failed 12 USBTC08 ERROR_PIPE_INFO_ FAIL Can not get USB pipe information 13 USBTC08 ERROR NOT CALIBRATED No calibration date was found 14 USBTC08_ERROR_PICOPP_
20. Store a handle returned from usb tc08 open unit instead of using the serial port number USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 14 Example The following code is a fragment of a C application demonstrating how to use legacy mode with the USB TC 08 driver e Setting up and running the unit in Legacy mode This is designed to make it easier to adapt code written for the Serial TCO8 for use with the USB TC08 les usb_tc08 set _mains handle 0 use 50Hz mains noise rejection for channel 1 channel lt 9 channel t set each channel up as a type K thermocouple switch off filtering for all channels usb _tc08 legacy _ set channel handle channel K 0 usb_tc08 legacy run handle last_cycle_no 0 no_of_readings 0 while no_of_readings lt 50 collect 50 readings usb_tc08 legacy get cycle handle amp this_cycle_no if last_cycle_no this_cycle_no last_cycle_no this_cycle_no no_of_readingst for channel 1 channel lt 9 channel t usb_tc08 legacy _get_temp amp reading channel handle channel 0 now do something with the readings check that they have not overflowed by comparing each reading with 2147483647L or LONG MAN include limits h usb _tc08 legacy get cold junction handle amp cold_junction now do something with the cold junction tempera
21. TOO_OLD An old picopp sys driver was found on the system Note These reserved error code values are only meaningful to Pico technical support staff but they are supplied to allow developers to display warnings in their applications For more details on error codes see troubleshooting Arguments handle Specifies the USB TC 08 unit Returns 1 Invalid handle Error code See the error code information above for further explanation USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 24 3 3 3 3 3 3 1 3 3 3 2 New USB mode only usb_tc0O8_set_channel short usb_tc08_set_channel short handle short channel char tc_type Call this routine once for each channel that you want to use You can do this any time after calling usb _tc08 open unit By default all channels are disabled Arguments handle Specifies the USB TC 08 unit channel Specifies which channel you want to set the details for this should be between 0 8 0 denotes the cold junction tc_type Specifies what type of thermocouple is connected to this channel Set to one of the following characters B E J K N R S T Use a space in quotes to disable the channel Voltage readings can be obtained by passing X as the character Returns 0 Use usb tc08 get last error 1 Routine was successful
22. Troubleshooting The following table lists each of the error codes described in the usb tc08 get last error section and divides them into categories so that you know what to do in the event of a particular error occurring Error code Description Category 1 USBTC08_ERROR_OS_NOT_SUPPORTED P 2 USBTCO08_ERROR_NO_CHANNELS_ SET P 3 USBTC08_ERROR_INVALID_PARAMETER P 4 USBTCO8 ERROR_VARIANT_NOT_ SUPPORTED P 5 USBTC08_ERROR_INCORRECT_MODE P 6 USBTC08_ERROR_ENUMERATION_INCOMPLETE S 7 USBTC08_ERROR_NOT_RESPONDING S 8 USBTC08_ERROR_FW_FAIL S 9 USBTC08_ERROR_CONFIG_FAIL S 10 USBTCO8_ ERROR_NOT_FOUND S 11 USBTC08_ERROR_THREAD_FAIL S 12 USBTC08_ERROR_PIPE_INFO_FAIL S 13 USBTC08_ERROR_NOT_CALIBRATED S 14 USBTC08_ERROR_PICOPP_TOO_OLD S Key S Errors in this category indicate that a fault has occurred with the USB TC 08 unit or your PC Try disconnecting the USB TC 08 then reconnecting it If this does not work restart your PC If this does not work do the following 1 Uninstall the software and restart the PC 2 Reinstall the software and restart the PC 3 If this does not work download the latest version of the software from http Awww picotech com download html and install this then restart the PC 4 If this does not work contact support picotech com P Errors in this category are handled internally within software applications and only developers need to be aware of their
23. _driver_version 15 32 usb_tc08_legacy_get_temp 15 31 usb_tc0O8_legacy_get_version 15 32 usb_tcO8_legacy_run 15 29 usb_tc08_legacy_set_channel 15 30 usb_tcO8_open_unit 15 16 usb_tcO8_open_unit_async 15 17 usb_tcO8_open_unit_progress 15 18 usb_tcO8_run_ 15 24 usb_tcO8_set_channel 15 24 usb_tcO8_set_mains 15 19 usb_tcO8_ stop 15 19 usb_tc0O8_temp_deskew 28 V Visual Basic 35 2005 Pico Technology Limited All rights reserved Pico Technology Ltd The Mill House Cambridge Street St Neots PE19 1QB United Kingdom Tel 44 0 1480 396 395 Fax 44 0 1480 396 296 Web www picotech com USBTC08044 2 1 7 05
24. a 0 USBTC08_UNITS_CENTIGRADE 1 USBTC08_UNITS_FAHRENHEIT 2 USBTCO08_UNITS_KELVIN 3 USBTC08_UNITS_RANKINE Voltages are always returned in millivolts fill_missing Choose whether or not to replace QNaN values with the last known value 0 Use QNaNs to represent missing readings 1 Fill missing readings with previous good reading Returns l An error occurred use usb tc08 get last error to get the code 0 Currently no readings to collect gt 0 Number of readings copied into array there may still be more readings in the driver s internal buffer USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 28 3 3 3 5 usb_tc0O8_get_temp_deskew long usb_tc08_get_temp_deskew Shes handle float temp long times long butter length short overflow short channel short units short fill_missing Same as usb tc08 get temp but the times take account of small differences caused by the order in which channels are converted Note Unless there is a specific reason to use the usb_tc08_get_temp_deskewed routine use usb_tc08_get_temp instead Arguments handle Specifies the USB TC 08 unit temp Pointer to a location where the temperature is to be placed times_ms_buffer Returns the exact time that this channel was converted optional buffer_length Specifies t
25. andle Specifies the USB TC 08 unit version Pointer to a location where the version number is to be stored Returns 0 Invalid handle 1 Retrieval of version number successful 2005 Pico Technology Limited All rights reserved USBTC08044 2 33 USB TC 08 Help 3 3 4 7 usb_tc08_legacy_get_cycle short usb_tc08_legacy_get_cycle long cycle short handle This routine gives the number of complete cycles of readings taken from a particular USB TC 08 Calling usb tc08 legacy get temp causes the most recent reading for the specified channel to be returned immediately If you wish to record values only when the driver has taken a new reading you can use this routine to find out how many complete cycles of readings the driver has taken Then you can call usb tc08 legacy get temp but only when the cycle has been incremented Arguments handle Specifies a USB TC 08 unit cycle Pointer to a location where the cycle number is to be stored Returns 0 Use usb tc08 get last error 1 Legacy get cycle successful Tip Do not test for an exact cycle number instead test for a different cycle number as your application may have missed readings See the Legacy mode section for an example Note Do not call this function unless you are operating the USB TC 08 in legacy mode having called usb tc08 legacy run USBTC08044 2 2005 Pico Technology Limited
26. bridgeshire PE19 1QB United Kingdom Phone 44 0 1480 396395 Fax 44 0 1480 396296 Email Technical Support support picotech com Sales sales picotech com Web site www picotech com USBTC08044 2 2005 Pico Technology Limited All rights reserved Product information Product information Specifications Resolution 20 bits 16 25 NFR Thermocouple types B E J K N R S T Number of input channels 8 Conversion time per active channel 100 ms Conversion time CJC 100 ms Uncalibrated accuracy The sum of 0 2 and 0 5 C Full scale input 70 mV Common mode range 7 5 V Overvoltage protection 30 V Input impedance 2 MQ Input connectors 8 x miniature thermocouple Output connector USB upstream connector Power requirements No power supply required Environmental conditions 0 to 50 C 25 to 75 humidity Quoted accuracy over 20 30 C NOT water resistant Note The resolution and accuracy depend upon the thermocouple type and the temperature range Below is a list of the thermocouples and temperature ranges supported by the USB TC 08 Actual measurable range Theoretical ranges CJC 5 C to 70 C N a Type B 20 C to 1820 C CJC must be 0 C to 1820 C gt 20 C Type E 270 C to 910 C 270 C to 1000 C Type J 210 C to 1200 C 210 C to 1200 C Type K 270 C to 1370 C 270 C
27. cation here Z 2005 Pico Technology Limited All rights reserved USBTC08044 2 17 USB TC 08 Help 3 3 2 2 Start using the open units as usb_tc0O8_open_unit_async short usb_tc08_open_unit_asynec void This routine begins enumerating USB TC 08 units in the background and provides a return immediately so the calling thread can continue executing other code Note The driver is thread safe and will not allow access to a single unit from more than one application If therefore usb_tc08_open_unit_async does not find a unit check that other applications are not using the same USB TC 08 This includes applications on other user accounts on the same computer where fast user switching is supported Arguments None Returns 1 The call was successful 0 No more units were found ch An error occurred call usb tc08 get last error with a handle of 0 to obtain the error code Example The following code is a fragment of a C application which demonstrates how to open a single unit with the asynchronous open unit functions Z Opening a unit asynchronously Tell the driver to start enumerating the unit in the background usb_tc08_open_unit_asynec returns immediately result usb tc08 open unit _async handle any error conditions if result 1 error_code usb_tc08_ get _last_error 0 printf Uni
28. e from copper and constantan are highly accurate and operate in the 270 C to 400 C temperature range 2005 Pico Technology Limited All rights reserved USBTC08044 2 39 USB TC 08 Help USB Universal Serial Bus This is a standard port that enables you to connect external devices to PCs A typical USB 1 1 port supports a data transfer rate of 12 Mbps 12 megabits per second and is much faster than a COM port USBTC08_INFO typedef struct tUSBTCO8Info short size short DriverVersion short PicoppVersion short HardwareVersion short Variants char szSerial USBTC0O8_MAX SERIAL CHARS char szCalDate USBTCO8_MAX DATE CHARS USBTCO8_INFO LPUSBTCO8_INFO This structure is used to receive information from the usb tc08 get unit info function and is defined in the usbtc08 h header file Note If the programming language you are using does not support structures use the usb tc08 get formatted info function USBTC08044 2 2005 Pico Technology Limited All rights reserved Index Index C C C 34 34 Cold junction 9 Connection 2 Contact details 7 D Del DLLs Driver routines E Error codes Excel 34 10 phi 15 usb_tc08_close_unit 15 19 usb_tc08_get_formatted_info usb_tc08_get_last_error 15 15 21 22 usb_tc08_get_minimum_interval_ms 15 20 usb_tc08_get_single 15 25 usb_tc08_get_temp 15 26
29. ects the readings Sleep 10000 use a two dimensional array with an array of readings for each channel In a real application this would be a nested loop to regularly poll the unit for readings for channel 0 channel lt 9 channel t no_of_readings usb tc08 get _temp handle amp reading_buffer channel amp times_buffer channel buffer_length amp overflows channel channel 0 degrees Celsius units 0 do not fill missing readings u L finished polling now do something with the readings if overflows channel is high then one of the readings in reading_buffer channel has exceeded the input range of the USB TC 08 only stop the unit when we ve completely finished streaming usb_tc08_ stop handle Note You should close down all other applications while you are performing any timing critical data logging tasks Check that the Windows scheduler does not have any activities planned during the logging session Get Single mode Get Single mode is an operational mode in which readings are produced on demand using the usb tc08 get single function Since the function relies entirely on the timing of the calling application it is ideal for time intervals greater than 1 minute If high speed sampling is required use Streaming mode USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 12 Note The function call
30. en informed of these conditions and agree to abide by them Usage The software in this release is for use only with Pico products or with data collected using Pico products Copyright Pico Technology Limited claims the copyright of and retains the rights to all material software documents etc contained in this release You may copy and distribute the entire release in its original state but must not copy individual items within the release other than for backup purposes Liability Pico Technology and its agents shall not be liable for any loss damage or injury howsoever caused related to the use of Pico Technology equipment or software unless excluded by statute Fitness for purpose No two applications are the same Pico Technology cannot guarantee that its equipment or software is suitable for a given application It is your responsibility therefore to ensure that the product is suitable for your application Mission critical applications This software is intended for use on a computer that may be running other software products For this reason one of the conditions of the licence is that it excludes usage in mission critical applications for example life support systems Viruses This software was continuously monitored for viruses during production however you are responsible for virus checking the software once it is installed Support If you are unsatisfied with the performance of this software please contac
31. gs are always placed in the array subscript corresponding to the channel number Channels which are not enabled are filled with QNaN values overflow_flags Pointer to a variable containing a set of bit flags that are set high when an overflow occurs on a particular channel An overflow occurs when the input signal is higher than the measuring range of the USB TC 08 The lowest significant bit bit 0 represents channel O0 the cold juction channel and bit 8 represents channel 8 the last thermocouple channel Bitwise comparisons should be performed to determine the overflow state of each channel units Specifies the temperature units for returned data 0 USBTC08_UNITS_CENTIGRADE 1 USBTCO08_UNITS_FAHRENHEIT 2 USBTC08_UNITS_KELVIN 3 USBTC08_UNITS_RANKINE Returns 0 An error occurred use usb tc08 get last error to get the code 1 The function succeeded USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 26 3 3 3 4 usb_tc0O8_get_temp long usb_tc08_get_temp short handle float temp_buffer long times_ms_buffer long buffer_length short overflow short channel short units short fill missing Once you open the driver and set up some channels you can call the usb _tc08 run routine The driver will then begin to continually take readings from the USB TC 08 Use the usb_tc08_get_temp routine to retrieve reading
32. he length of the sample buffer overflow Pointer to a variable that will be assigned a value of 1 if an overflow occured on any of the readings copied into temp_buffer or 0 if an overflow did not occur An overflow occurs when the input signal is higher than the measuring range of the USB TC 08 channel Specifies the channel to read the temperature from units Specifies the temperature units in which the data are returned 0 USBTC08_UNITS_CENTIGRADE 1 USBTC08_UNITS_FAHRENHEIT 2 USBTC08_UNITS_KELVIN 3 USBTC08_UNITS_RANKINE Voltages are always returned in millivolts fill missing Choose whether or not to replace QNaN values missing readings with the last known value 0 Use QNaNs to represent missing readings 1 Fill missing readings no QNaNs 2005 Pico Technology Limited All rights reserved USBTC08044 2 29 USB TC 08 Help Returns An error occurred use usb tc08 get last error to I get the code 0 Currently no readings to collect gt 0 Number of readings copied into array there may still be more readings in the driver s internal buffer 3 3 4 Legacy mode only 3 3 4 1 usb_tc08_legacy_run short usb_tc08_legacy_run short handle This routine starts the sampling thread and forces the specified unit to run in legacy mode Arguments handle Specifies the USB TC 08 unit Retur
33. ll rights reserved USBTC08044 2 35 USB TC 08 Help 3 4 4 Excel The easiest way to transfer data to Excel is to use the PicoLog software application If however you need to do something that is not possible using PicoLog you can write an Excel macro which calls usbtc08 d11 to read in a set of data values The Excel Macro language is similar to Visual Basic The example USBTC0832 XLS reads in 20 values of the cold junction temperature and channel 1 temperature one per second and assigns them to cells A1 B20 3 4 5 LabVIEW While it is possible to access all of the driver routines described earlier it is easier to use the special LabVIEW access routine To use this routine copy usb_tc0832 vi from the DRIVERS subdirectory to your LabVIEW user 1ib directory You will then need usb_tc08 sub vi and an example sub vi which demonstrate how to use them You can use one of these sub vis for each of the channels that you wish to measure The sub vi returns a temperature for thermocouple types 3 4 6 Visual Basic The DRIVERS directory contains the following files created in Visual Basic 6 USBTC0832 VBP USBTC0832 BAS USBTC0832 FRM USBTC0832 VBW 3 4 7 HP Vee The example program usb_tc08 vee shows how to collect a block of data from the usb_tc08 There are prototypes in USB_TCO8 vh USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 36 3 5
34. meration process For an example of usage see usb tc08 open unit async Arguments handle incomplete Out A handle positive short to the unit if the enumeration is completed Handle will always be 0 if the enumeration is progress Out Optional can pass NULL returns a number from 0 to 100 representing the percentage completion of the enumeration of one unit Returns 1 USBTCO8_PROGRESS_FAIL An error occurred call usb tc08 get last error witha handle of 0 to obtain the error code T D USBTC08 PROGRESS PENDING Enumeration has not completed keep calling usb_tc08_open_unit_progres s 1 USBTCO8_PROGRESS_COMPLETE Enumeration has completed and the handle is now valid 2005 Pico Technology Limited All rights reserved USBTC08044 2 19 USB TC 08 Help 3 3 2 4 usb_tcO8_close_unit short tc0O8_close_unit short handle This routine closes the unit for a specified USB handle Arguments handle Specifies the USB TC 08 unit Returns 0 Use usb tc08 get last error 1 Unit closed successfully Note If you successfully open any USB TC 08 units call usb tc08 close unit for each handle before you exit from your program If you do not there is a chance that the unit will not reopen until it has been disconnected and reconnected 3
35. nennnennnensnennnensnensnnnsennnnnnnonnennnennnennnnnn 37 Index sssssssssnnsnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnmnnn 40 2005 Pico Technology Limited All rights reserved Introduction 2 1 1 1 1 2 1 3 Introduction Overview The USB TC 08 is a temperature and voltage logger designed to support multiple thermocouples With the accompanying PicoLog software the unit can be used with any laptop or PC running Windows 98SE ME 2000 XP or higher If you are technically minded and want to tailor the product to a particular application you can write your own programs with the supplied driver The driver provides cold junction compensation for thermocouples PicoLog supports up to 10 USB TC 08 devices and the driver can support more as many as 64 if you have a high specification PC This manual describes the physical and electrical properties of the USB TC 08 and provides an explanation of how to use the software drivers For information on PicoLog please consult the PicoLog help file Installing the driver The driver is installed automatically when you install the PicoLog software Alternatively you can download the driver from our website at http www picotech com Connecting the USB TC 08 Please note do not connect the USB TC 08 until you have installed the software and restarted your PC To begin using the USB TC 08 connect it to the USB port
36. ns 0 Use usb tc08 get last error 1 Legacy run successful 2005 Pico Technology Limited All rights reserved USBTC08044 2 Technical reference 30 3 3 4 2 usb_tc08_legacy_set_channel short usb_tc08_legacy_set_channel short handle short channel char tc_type short filter_factor short offset short slope Call this routine once for each channel that you would like to take readings from You can do this any time after calling usb tcO8 open unit Arguments handle Specifies the USB TC 08 unit channel Specifies which channel you want to set the details for This should be between 0 and 8 tc_type Specifies what type of thermocouple is connected to this channel Set to one of the following characters B E J K N R S T Use a space in quotes to disable the channel filter_factor Specifies the size of the median filter Each time the driver takes a reading from this channel it updates the filtered value by adding a reading to a median filter The filter factor can be set to any value between 0 255 0 or 1 turns filtering off filter_factor These parameters are provided for backward compatibility with the serial TC 08 and have no effect when used with the USB TC 08 Returns 0 Use usb tc08 get last error 1 Legacy set channel successful Note Do not call this function unless you are
37. ot find a unit check that other applications are not using the USB TC 08 This includes applications on other user accounts on the same computer where fast user switching is supported Note The usb_tc08_open_unit function provides a simple way to open USB TC 08 units However the function call locks up the calling thread until the attached USB TC 08 unit has been fully enumerated If a single threaded application needs to perform concurrent processing such as displaying a progress bar use usb tc08 open unit async Arguments None Returns Positive short The handle to a unit 0 No more units were found 1 Unit failed to open Call uso tc08 get last error with a handle of 0 to obtain the error code Example The following code is a fragment of a C application which demonstrates how to open multiple units with the USB TC 08 driver The handles to the open units are stored in an array for later use Opening multiple units ff for i 0 new_handle usb tc08 open unit gt 0 i store the handle in an array handle_array i new_handle no_of_units i deal with the error if there is one if new_handle was zero then there was no error and we reached the last available unit if new_handle 1 error_code usb tc08 get last _error 0 printf Unit failed to open nThe error code is d error_code could terminate the appli
38. overhead can be significant since it takes approximately 360 ms to convert all 9 channels equating to 40 ms per channel To reduce this overhead disable channels that are not required Example The following code is a fragment of a C application demonstrating how to use Get Single mode with the USB TC 08 driver Setting up and converting readings with Get Single mode usb _tc08 aer mains handle 0 use 50Hz mains noise rejection for channel 0 channel lt 9 channel t set each channel up as a type K thermocouple channel 0 is the cold junction and will be enabled by setting the third argument to anything other than usb_tc08_set_channel handle channel K 1 U find out the approximate conversion time for a call to usb_tc08_get_single minimum_interval usb _ tc08 oer _minimum_interval_ms handle printf Conversion time d n minimum_interval Collect 10 readings over approximately 9 minutes last_time GetTickCount for i 0 i lt 10 i do the conversion for all channels usb_tc08_ get _single handle value_array short value_array 9 amp overflow_flags 0 degrees Celsius units print out the values printf n nTime d minute s i for c 0 c lt 9 c check for overflows on each channel with a bitwise amp comparator shift the comparison bit to match the channel if overflow_flags amp 1 lt
39. s from the driver s buffer periodically You must call the function at least once per minute to avoid losing data the driver s buffer is circular so the oldest readings will be overwritten first Streaming mode relies on the driver to buffer readings without interruption If the driver does not get enough share of the PC s processor time the most frequent cause of which is too many applications running at the same time readings will be dropped and the sample buffer will be padded with QNaN floating integers Warning The padding of the buffer is also dependent on the performance of the PC and under very heavy processor loading padding may not always be accurate 2005 Pico Technology Limited All rights reserved USBTC08044 2 27 USB TC 08 Help Arguments handle Specifies the USB TC 08 unit temp_buffer Pointer to a location where the readings are to be placed times_ms_buffer Returns the time that the first channel was converted optional buffer_length Length of data buffers overflow Pointer to a variable that will be assigned a value of 1 if an overflow occured on any of the readings copied into temp_buffer or 0 if an overflow did not occur An overflow occurs when the input signal is higher than the measuring range of the USB TC 08 channel Specifies the channel to read the temperature from units Specifies the temperature units for returned dat
40. sb tc08 legacy run USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 32 3 3 4 4 3 3 4 5 3 3 4 6 usb_tc08_legacy_get_cold_junction short usb_tc08_legacy_get_cold_junction long temp short handle This routine retrieves a cold junction temperature reading This can also be achieved by passing channel 0 to usb tc08 get temp Temperatures are returned in hundredths of a degree Celsius Normally you do not need to worry about the cold junction temperature as the driver automatically uses it to compensate thermocouples You can however use it as an indication of ambient temperature Arguments handle Specifies USB TC 08 unit temp Pointer to a location where the temperature reading is to be stored Returns 0 Use usb tc08 get last error 1 Retrieval of cold junction temperature reading successful usb_tc08_legacy_get_driver_version short usb_tc08_legacy_get_driver_version void This routine returns the driver version This is useful when you need to find out if the latest driver is being used Arguments none Returns Driver version number usb_tc08_legacy_get_version short usb_tc08_legacy_get_version short version short handle This routine sets the version variable to match the version of the USB TC 08 currently being used Arguments h
41. t failed to open nThe error code is d error_code could terminate the application here else if result 0 printf No USB TCO8 units found could terminate the application here No errors so start polling usb_tc08_open_unit_progress continuously for its enumeration state do result usb tc08 open unit progress amp handle amp progress switch result USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 18 case USBTC08_PROGRESS_FAIL error_code enum equates to usb_tc08_ get last error 0 printf Unit failed to open nThe error code is d error_code could terminate the application here break case USBTC08_PROGRESS_PENDING printf nThe unit is 6d percent enum equates to 0 numerat Sleep 500 break case USBTCO08_PROGRESS_COMPLETE wait for approx Ea printf n nThe unit with handle break while handle result USBTCO8_PROGR Start using the open unit 3 3 2 3 usb_tcO8_open_unit_progress short usb_tc08_open_unit_progress d progress half a second enum equates to 1 MC 7 opened successfully ESS_PENDING short handle short progress Call this function after usb_tc08_open_unit_async Repeatedly call it to determine the state of the background enu
42. t our technical support staff who will try to fix the problem within a reasonable time scale If you are still unsatisfied please return the product and software to your supplier within 28 days of purchase for a full refund Upgrades We provide upgrades free of charge from our web site at www picotech com We reserve the right to charge for updates or replacements sent out on physical media USBTC08044 2 2005 Pico Technology Limited All rights reserved Introduction 6 Trademarks Pico Technology Limited PicoScope PicoLog DrDAQ and EnviroMon are trademarks of Pico Technology Limited and are registered in the United Kingdom and other countries Pico Technology acknowledges the following product names as trademarks of their respective owners Windows Excel Visual Basic LabVIEW Agilent VEE HP VEE Delphi 1 5 Safety warning We strongly recommend that you read the general safety information below before using your product for the first time If the equipment is not used in the manner specified then the protection provided may be impaired This could result in damage to your computer and or injury to yourself or others Maximum input range The USB TC 08 is designed to measure voltages in the range of 70 mV Any voltages in excess of 30 V may cause permanent damage to the unit Mains voltages Pico products are not designed for use with mains voltages Safety grounding The ground of every product is
43. ture usb Ce stop handle 2005 Pico Technology Limited All rights reserved USBTC08044 2 15 USB TC 08 Help 3 3 3 3 1 Driver routines Introduction The following table explains each of the USB TC 08 routines Routine Description New USB and serial mode usb tc08 open unit Opens the USB TC 08 unit and gets a valid USB handle usb tc08 open unit async Opens the unit asynchronously usb tc08 open unit progress Polls the unit s enumeration progress during asynchronous operation usb tc08 close unit Closes the handle usb tc08 stop Stops the unit streaming usb tc08 set mains Sets the mains interference rejection filter to either 50 Hz or 60 Hz usb tc08 get minimum interval ms Returns the minimum sampling interval for the Current setup usb tc08 get unit info Retrieves information on a particular unit and presents it as a structure usb tc08 get formatted info Retrieves information on a particular unit and presents it in string form usb tc08 get last error Returns the last error for a specified unit or for a call to open a unit New USB mode only usb tc08 set channel Sets up a USB TC 08 channel usb tc08 run Starts the USB TC 08 unit streaming usb tc08 get single Converts readings from currently set up channels on demand usb tc08 get temp In streaming mode retrieves tempera
44. ture readings from a specified channel usb tc08 get temp deskew In streaming mode retrieves temperature readings from a specified channel with time deskewed Legacy mode only usb tc08 legacy run Starts the USB TC 08 unit running in legacy mode usb tc08 legacy set channel Sets up a USB TC 08 channel usb tc08 legacy get temp Retrieves temperature readings from a specified channel usb tc08 legacy get cold junction Retrieves a temperature reading for the cold junction usb tc08 legacy get driver version Returns the driver version usb tc08 legacy get version Returns the hardware version of the USB TC 08 unit usb tc08 legacy get cycle Returns the number of readings taken so far USBTC08044 2 2005 Pico Technology Limited All rights reserved Technical reference 16 3 3 2 New USB mode and legacy mode 3 3 2 1 usb_tcO8_open_unit short usb_tc08_open_unit void This routine returns a valid handle to the USB TC 08 if the driver successfully opens it If the routine fais see the error code explanations in the usb tc08 get last error section If you wish to use more than one USB TC 08 call this routine once for each unit connected to the PC The function will return O if there are no more units found The driver is thread safe and will not allow access to a single unit from more than one application If therefore usb_tc08_open_unit does n
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