CTU LabVIEW VI User Guide
Contents
1. Cambridgel C dll FTDI DLL Interface ftd2xx dll software A y Windows CTU Adapter Driver A i Resonant Inductive Position Sensing System USB Interface y Target gt spi Customer test CAM204A Interface CambridgelC lt gt e Sensor PCB CTU Chip CTU Adapter equipment Figure 1 System block diagram Document part no 033 0008_0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 1 of 16 CTU LabVIEW VI User Guide Cambridge IC 1 Introduction 1 1 Audience This document assumes the reader is familiar with programming in National Instruments LabVIEW 1 2 Software Design The software is designed to run in the environment illustrated in Figure 1 The PC is connected to a CambridgelC CTU chip with a CTU Adapter using a USB port The Virtual Instruments VIs described in this document are coded using National Instruments LabVIEW graphical programming language They require LabVIEW to be installed on the target PC LabVIEW can alternatively be used to build stand alone applications providing Application Builder is installed The VIs use two DLLs for communicating with the CTU Adapter The higher level one is Cambridge C DLL and this contains all of the functions required to send data to and from a CTU chip over its SPI interface together with functions for controlling the Adapter itself The Adapter contains a chip for US2. i Integrated Circuits Ltd ai E SlPVisib Fe Multi CTU support O none 1 SPI Expander J Incremental Type 2 Position results Amplitude results fv Relative frequency results T Requested num VALID SinLength DEL Measurement statistics CambridgeIC_CTU_Software_2x lvproj My Computer a Figure 7 CTU Repeat Average block diagram VIs which are distributed as CambridgelC CTU Software applications including CTU Repeat Average use the sub VI GetLogo to retrieve an image of the CambridgelC logo from the file logo bmp Other VIs display a fixed default logo Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 7 of 16 CTU LabVIEW VI User Guide Cambridge IC 5 Reading Multiple Sensors CtuDemo can read measurement results from multiple sensors connected to the CAM204A CTU chip providing the Sensor Type allows it Its operation is detailed in the CambridgelC CTU Software User Guide Unlike previous examples CtuDemo can operate in the CTU s continuous mode CONT TRUE as well as single shot mode CONT FALSE When operating in continuous mode the VI uses the CTU s sample indicators to signal when all active sensors have completed measurement Using sample indicators requires the CTU s SIC register to be configured The SIC contents cluster constant determines settings SMAP maps each sensor s sample indicator to the user I0 pin of the same number SCTRL 1 means sample in
3. Ltd 2009 2010 Page 12 of 16 CTU LabVIEW VI User Guide Cambridge IC File name minus _2x vi InterpretType2Results IterationsPerSec PauseComms PauseSingleShot QuickStart SaveToFile SelectSpiSlave U16tol 16 UnwrapPhaseAngle Description As above but for a Type 2 sensor Also works for Type 3 This VI can be used to determine an approximate number of iterations per second using the PC s internal clock Called by CtuDemo to measure update rate see section 5 This VI pauses operation for the specified number of milliseconds It is used where a delay is required for example within CtuPowerControl to ensure that the change in power state has time to take effect before the VI finishes It may also be used in loops to prevent LabVIEW from executing the loop so rapidly that it consumes all of the PC s CPU cycles Pauses for a length of time which depends on sensor Type to allow the next CTU measurement to complete before the PC attempts to read its results This VI performs commonly required configuration tasks for the CTU Adapter and the CTU itself It opens and configures the Adapter activates the power supply and SPI pull ups checks communications with the CTU including a reset configures the CTU s outputs and sets sensor type s See sections 3 4 5 for examples Saves measurements to file Called by CtuDemo and CtuRepeatAverage when Save to File is activated Takes data in the form of
4. chip and the results are displayed on the front panel Figure 4 shows the expected state of SCW decoded when CtuSimpleMeasureTypel is run with a target present GO FALSE cleared by CTU following successful measurement NEW TRUE new measurement results available and VALID TRUE target present The remainder of the bits of SCW reflect the values originally wired to CtuWriteReadResults Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 4 of 16 CTU LabVIEW VI User Guide KCambridge IC CtuSimpleMeasurelype1_2x vi Block Diagram on CambridgelC_CTU_Software_2x lvproj M SE Edit View Project Operate Tools Window Help So 1 2 25 ale or iss Integrated Circuits Ltd 7 ey Sensor Type 1 Adapte Close CambridgeIC_CTU_Software_2x lvproj My Computer lt j Figure 5 CTU Simple Measure Type 1 block diagram LabVIEW s Array Subset function is used to pick out the results registers RESA RESB and RESC These are wired to InterpretTypelResults This VI processes individual results and outputs them in a meaningful format as the cluster Processed results wired to the front panel CTU Reported Position is the raw CTU position output RESA interpreted as a signed 16 bit word This is scaled into physical units using the value of Sin Length Sin Length is quoted in a sensor s datasheet Set Sin Length to 360 for reported position in degrees when operating a 360 rotary type 1 sensor For typ
5. closed Error 5004 Read Adapter power selector link missing Check there is a link selecting between 2V7 3V3 timeout and 3V6 fitted through the Adapter s rear panel Error 5008 Adapter Adapter internal error Unplug the Adapter from the PC s USB port then Error plug it back in again and wait 5 seconds Error 5010 Exceeded Sample indicators not correctly Check the sensor s SIC register contents The max iterations waiting configured AUTOCLR bit should be FALSE and SCTRL TRUE for active IO SIC and 10 configuration not wired Wire the current multi channel SIC contents and to CtuWaitForSamplel ndicator 10 configuration to the VI The CTU s user lOs are not Connect them or connected to the CTU Use single shot mode instead of continuous Error 5012 Did not get Adapter to CTU SPI interface not Check SPI connections expected SYSID from properly connected CTU CTU chip not powered Check power is supplied to the CTU by the Adapter or other means Error 5013 SYSID CTU firmware update was Try uploading CTU firmware again Ox10AD CTU firmware interrupted while in progress missing Error 5107 Failed mid stream Upload CTU firmware Error 1172 occurred at A VI communicating with the Wire the Adapter reference output of the Error calling method Adapter does not have a valid previous VI that communicates with the Adapter Adapter reference input or to OpenAdapter CTU does not report A sensor or excitation coil Check se
6. B communication from FTDI This has its own DLL ftd2xx DLL which must also be loaded on the PC to enable CambridgelC DLL to communicate with the Adapter They are also included in the installer The Adapter requires a Windows driver whose installation is described in the CambridgelC CTU Software User Guide 1 3 Communication with Cambridgel C DLL LabVIEW communicates with Cambridge C DLL using NET controls which can be found in the connectivity tools palette There are sub VIs which communicate with the DLL in this way e g CtuPowerControl and it is not normally necessary to access such low level functions directly All Vis that communicate through the Adapter require a valid Adapter reference input which is generated by AdapterOpen or QuickStart They also output this reference and Adapter reference out should be wired to the next VI that communicates through the Adapter It is good practice to close an adapter reference before a main VI stops using AdapterClose However this is not essential Cambridgel C DLL requires ftdxx DLL for correct operation Both may be installed alongside the CambridgelC CTU Software using the installer described in the CambridgelC CTU Software User Guide They may alternatively be saved to the user s LabVIEW working directory 1 4 CTU Datasheet This document makes references to CTU register locations which are used to configure CTU chips and read back data The function of each of these registers is de
7. CTU LabVIEW VI User Guide Cambridge IC Description CambridgelC s Central Tracking Unit CTU chips work with sensors built from PCBs to measure the position of contactless targets using resonant inductive sensing technology CTU chips are designed to be embedded inside electromechanical products and communicate with a host system processor over an SPI interface To assist demonstration evaluation and development CambridgelC provides hardware and software that works with a PC A CTU Adapter enables a PC to communicate with CTU chips by converting between SPI and USB interfaces This document describes a set of LabVIEW Virtual Instruments VIs that communicate with Cambridgel C CTU chips using a PC connected to a CTU Adapter These VIs can be used to create custom applications that communicate with CTU chips Applications e Customised demonstrations e Customised test systems Features Simple example VI for taking measurements Example VI for taking averaged measurements Example VI for setting position triggers Full set of sub VIs for advanced communications Approximately 100 SPI transfers per second System Requirements e Windows XP Vista or Windows 7 e National Instruments LabVIEW software V 8 5 on Windows PC Customer VIs J CambridgelC VIs i National Instruments LabVI EW CambridgelC DLL
8. PI transaction This VI performs a read from the selected CTU register address Also returns IO states This VI performs a read from multiple CTU addresses The start address and number of addresses to read from are specified Called by CtuReadVerAndlD Also returns 10 states Reads bootloader and system versions and system ID Uses CtuReadRegisters to read from the 3 adjacent CTU registers involved Called by CtuResetAndCheck which is called by QuickStart Documented in the CambridgelC CTU Software User Guide and in section 4 Also demonstrates use of CtuMultiMeasureAndAnalyse Performs a CTU reset Checks that a reset has happened by checking that the SYSID register returns to its default value Returns CTU version information Called by QuickStart By default this VI uses CtuResetWithSpi to reset the CTU chip Type of reset 1 If Type of reset is instead set to 2 the Adapter uses CtuToggleResetPin instead which will only work if the Adapter s nRESET pin is connected to the CTU Performs a CTU reset over the SPI interface by writing to the SYSCW register Sets each sensor s SIC register by repeatedly calling CtuSetMultiSensorSamplelndicators Called by CtuDemo see section 5 Execute this VI to enter the CTUs power down mode Used in CtuDemo see section 5 Sets the CTU s SIC register of a single sensor from its individual components supplied as a cluster Called by CtuSetMultiSensorSamplel ndicators Writes to t
9. UpControl are run in a loop and controlled with appropriately named buttons SelectSpiSlave operates the SPI Expander if present The STOP control exits this loop whereupon AdapterClose is run to close communications with the Adapter AdapterTest_2x vi Block Diagram on CambridgelC_CTU_Software_2x Ilvproj My Computer SEE File Edit View Project Operate Tools Window Help Turn Power on Turn Pull Ups on CambridgeIC_CTU_Software_2x lvproj My Computer lt Figure 3 Adapter Test block diagram Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 3 of 16 CTU LabVIEW VI User Guide Cambridge IC 3 Taking Single Measurements This section describes how to use the VIs provided to take position measurements with a CTU chip It is based on the example application CtuSimpleMeasureTypel This VI can form the basis of simple demonstration and test applications When assessing CTU system performance it is usually best to use a VI that takes and processes multiple samples as described in the next main section This provides more insight into CTU performance since it measures the noise present in output data It also yields a higher resolution position output through averaging Figure 4 illustrates the front panel of CtuSimpleMeasureTypel Figure 5 shows the VI s block diagram QuickStart is used to configure and test the Adapter and CTU chip The constant Sensor Type is wired to QuickStart and is set for type 1 se
10. a text array First column is data label second is the data itself Selects which CTU device to select when a system has more than one on the SPI bus Requires an 12C controlled SPI bus Expander Used by CtuRepeatAverage among others See section 5 Included in QuickStart This VI converts a raw unsigned 16 bit word U16 to a signed 16 bit word 116 It is called by InterpretTypelResults to convert appropriate register contents to signed quantities Takes an input array of phase angles and wraps it to remove artificial phase jumps around 180 degrees This is important prior to performing an average and any other function that requires an input that is continuous Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 13 of 16 CTU LabVIEW VI User Guide Cambridge IC 7 Troubleshooting Guide Symptom Possible cause Rectification Error 5001 DEVICE Adapter not plugged into USB port Plug it in NOT FOUND Adapter driver not installed Install driver please refer to the CambridgelC CTU Software User Guide Adapter driver disabled Re Enable driver please refer to the CambridgelC CTU Software User Guide Adapter not yet enumerated Wait 5 seconds between plugging in the Adapter and running any application that uses it Error 5002 DEVICE A VI has been called with an Call OpenAdapter to create a new Adapter NOT OPEN Adapter reference input that has reference already been
11. ambridge IC 2 Checking Communications with the Adapter AdaptertTest is a simple application that can be used to check communications with the CTU Adapter The front panel is shown in Figure 2 When run it configures the CTU Adapter then turns on and off power and pull ups under control of two buttons Their state should be reflected in the state of the LEDs on the Adapter s physical front panel AdapterTest_2x vi Front Panel on CambridgelC_CTU_Sof BAR File Edit View Project Operate Tools Window Help AOTEA Cambridge IC ral Integrated creues ted V2 03 build 0001 Wed Mar Bootloader V2 01 build 001 CambridgeIC_CTU_Software_2x lvproj My Computer C_CTU_Software_2x Ivproj My Computer lt i i Figure 2 Adapter Test front panel AdapterTest also includes controls for an 12C controlled SPI Expander which may be used to select between CTU chips on the same SPI bus in multi CTU systems Multi CTU support should be set to 1 if an SPI Expander is connected or 0 otherwise Use the CTU to Select control to switch the SPI Expander between different CTU chips Although this VI does not actually communicate with CTU chips LEDs on the SPI Expander should light to indicate which is selected The block diagram is illustrated in Figure 3 Communications is first opened using AdapterOpen then the Adapter is configured using AdapterConfigure Adapter and VI information is retrieved using AdapterGetl nfo CtuPowerConrtrol and CtuPull
12. dicators are triggered on NEW measurements SAUTOCLR 0 means the CTU does not clear sample indicators itself Instead they are cleared by writing FALSE to the sample indicator flag SIF within each sensor s SCW register These values are written to each sensor s SIC registers using CtuSetMultiSensorSamplel ndicators Using continuous mode also requires a write to the CTU s SYSI register to change the interval between samples on each sensor timed by the CTU CtuSetSystem nterval is called from inside a case structure which is only TRUE when the value of SYSI changes CtuDemo_2x vi Block Diagram on CambridgelC_CTU_Software_2x lvyproj My Computer SEN File Edit View Project Operate Tools Window Help mo ler Faa Selected logo SIC contents sensor I0 NEW AUTOCLR 0 fee Selected logo ka x Iteratns fee x x x ers manag 5 10 to activate Wa Per Ser Actual updates b gt Full path of per P Full p ago second limited by PC SYSI interval in Launch save window continuous mode ms E Sensor Type Sensors active iv Adapter and DLL info Type of reset when run O none 1 SPI 2 nRESET pin 3 power cyde Luss 10 configuration in active low digital CONT continuous Lone f 2009 2010 Cambridge Integrated Circuits Ltd CambridgeIC_CTU_Software_2x lvproj My Computer lt Iw Figure 8 CTU Demo block diagram left hand end QuickStart s outputs include Sensor
13. e 1 linear sensors Sin Length is usually slightly greater than a sensor s Measuring Length Setting the Sin Length control to 100 yields reported position as a percentage of the sensor s actual Sin Length CtuWriteReadResults is run in a while loop that is stopped with the STOP button or on an error When stopped AdapterClose is run to close communications with the Adapter Then LabVIEW s built in VI Simple Error handler is called to highlight any errors that have occurred to the user CtuSimpleMeasureTypel calls CtuWriteReadResults continuously without any time delay in the loop Calls to CtuWriteReadResults can not be separated in time by any less than 1ms due to the PC s USB interface Since each Type 1 measurement takes the CTU chip less than lms measurement will always be complete NEW TRUE the next time the VI runs Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 5 of 16 CTU LabVIEW VI User Guide Cambridge IC 4 Taking and Processing Multiple Measurements CtuMeasureAndAnalyse takes multiple measurements from a selected sensor and processes the results to yield a set of Measurement statistics including Position Average and Position Std Dev standard deviation The number of measurements is set by Requested Num VALID A larger number yields more averaging so that the output Position Average has lower noise and higher resolution For every factor of 4 increase in Requested Num VALID res
14. f the CTU is waiting for firmware to be loaded Configures the CTU s IOs for active high or low and open drain or digital Converts cluster of input settings to appropriate SYSINT value and writes to the CTU s SYSINT register Calls CtuConfigurePositionTriggers multiple times to configure position triggers for all sensors Configures the CTU s position trigger registers Input parameters are processed to determine register settings then these are written to the CTU Called by CtuConfigureMultiSensorPositionTriggers Main demo application documented in the CambridgelC Software User Guide and in section 5 Displays measurement results in a separate window which depends on Sensor Type Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 10 of 16 CTU LabVIEW VI User Guide Cambridge IC File name minus _2x vi CtuExitPWRDN CtulnterpretSCW CtuMultiMeasureAndAnalyse CtuMultiWriteReadResults CtuNumberResults CtuPowerControl CtuPullUpControl CtuReadl Os CtuReadRegister CtuReadRegisters CtuReadVerAndl D CtuRepeatAverage CtuResetAndCheck CtuResetWithSpi CtuSetMultiSensorSample Indicators CtuSetPwrdn CtuSetSamplel ndicatorControl CtuSetSensorType CtuSetSensorTypeMultiSensor Description Execute this VI to exit the CTUs power down mode Used in CtuDemo see section 5 The CTU s sensor control word register contains bits for con
15. he Adapter at a low level Not normally required Communicates with the Adapter at a low level Not normally required Processes a Set of raw valid CTU measurements and outputs processed data series plus statistics Called by CtuMultiMeasureAndAnalyse Used to create an array of SCW register controls one for each sensor for passing to CtuWriteReadResults As below but calls UnwrapPhaseAngle to handle the discontinuity between 180 if rotary Used by AnalyseMultiCtuResults to calculate the average standard deviation and peak deviation from average of the input array Calculates the contents of the CTU s PTEF register from arrays containing individual enables and flags Called by CtuWriteReadResults Calculates the contents of the CTU s SCW register from its individual contents formatted as a cluster Called by CtuWriteReadResults Performs a register write read to the SYSID register location to change the value read out during the address word of all subsequent SPI data transactions This VI is used to test for successful CTU reset within CtuResetAndCheck All other Vis that communicate with the CTU check for the default value of SYSID and will normally return an error if the value has been changed When run the VI returns the previous value of SYSID before the change as reported over the SPI interface and not the newly programmed value Checks whether its SYSID input matches the expected value Generates errors if not or i
16. he CTU s TYPE register location for a selected sensor to configure that sensor for the specified Sensor Type Called by CtuSetSensorTypeMultiSensor The CTU can be configured to measure multiple sensors and that number depends on Sensor type This VI writes the same Sensor TYPE to all possible Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 11 of 16 CTU LabVIEW VI User Guide W Cambridge IC File name minus _ 2x vi Description sensors for that type Also lists which sensors are possible in the form of a Boolean array Calls CtuSetSensorType Called by QuickStart CtuSetSystemInterval Writes to the CTU s SYSI register which specifies the interval between measurements on a particular sensor when the sensor is operating in continuous mode Called by CTU demo see section 5 CtuSimpleMeasureTypel Example VI described in section 3 Takes measurements from a selected Type 1 sensor CtuToggleResetPin This VI toggles the Adapter s nRESET output pin low for a short period which will reset the CTU if nRESET is connected to it CtuWaitForSamplel ndicator When called this VI runs until a sensor s sample indicator becomes valid It is used by CtuDemo to pause communications until the CTU reports that new measurements are available using sample indicators see section 5 This VI requires SIC register contents for each active sensor as an input so that it knows which IO and to test and
17. ir front panels CtuDemo_2x vi Block Diagram on CambridgelC_CTU_Software_2x lvproj My Computer DER le Edit View Project Operate Tools Window Help 1 kabale s a pee F p32 Actual updates per second limited by PC ee ee EESE E S We e yg E a Launch save window T AA Senzor IO configuration SIC contents ous g i Power downmode in 2009 2010 Cambridge E Integrated Circuits Ltd Fon ONE naen imbridgeIC_CTU_Software_2x lvproj My Computer lt i Iv S Figure 9 CTU Demo block diagram right hand end If the system is running in continuous mode CtuDemo now waits for the sample indicator of the highest numbered active sensor to become active signaling that new measurements are ready and the main while loop can execute again to collect this next set of measurements HighestActiveSensor takes the Sensors active array and determines which is the highest numbered active sensor It then passes this value to CtuWaitForSamplel ndicator which runs until that sample indicator becomes active CtuDemo includes a front panel button which appears as Power down mode in Figure 9 and allows the user to control the CTU s PWRDN bit in its SYSCW register This causes the CTU to cease measurements in progress and enter a low power mode CtuSetPwrdn is used to enter this mode and CtuExitPwrdn is used to exit Document part no 033 0008_0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 9
18. nsor and its connections VALID when a target is connection is missing or shorted present A Type 2 sensor is being used with Change Sensor Type to match the sensor type Sensor Type set to 1 connected The CTU is measuring a different Check that Sensor number matches the CTU Type 1 sensor input number that the sensor is connected to The CTU is measuring an invalid Check that Sensor number is set to 1 for a Type Type 2 sensor number 2 sensor The CTU s excitation circuit is not Check the circuit conforms to the CTU datasheet working The target is not working Try a different target The target s frequency has been Check for metal closer to target and sensor than changed by nearby metal beyond specified in their datasheets the CTU s tuning range Misaligned target Check sensor datasheet for correct alignment of Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 14 of 16 CTU LabVIEW VI User Guide Cambridge IC Symptom Possible cause Rectification Pp sensor and target Reported position does A sensor coil connection is missing Check sensor and its connections not change smoothly or shorted with target position A Type 1 sensor is being used with Change Sensor Type to match the sensor type Sensor Type set to 2 connected Reported position in Incorrect value of Sin Length for Check that the value used matches the mm or degrees the sensor appropriate value from the sensor s data
19. nsors QuickStart has an output Adapter and DLL info which is wired to the front panel and lists version and serial number information for the Adapter and DLL It also outputs CTU info which lists version and System ID information for the CTU chip The Sensor number control selects which sensor to measure This is wired to the VI that actually instructs the CTU to take measurements CtuWriteReadResults This VI also requires SCW register contents as an input supplied as a cluster constant on the block diagram GO is set to TRUE to kick off another measurement CONT is set to FALSE so that the CTU operates in single shot mode That way each time the PC collects one set of measurements the CTU will start measuring again NEW is set to FALSE so that the sensor s NEW flag is reset The state of the other controls within SCW do not matter for this application CtuSimpleMeasureType1_2x vi Front Panel on Ca DER Eile Edit View Project Operate Tools Window Help V2 03 build 0001 Wed Mar 24 16 58 12 2010 TT Bootloader V2 01 build 001 TT CambridgeIC DLL Version Vendor ID Product ID Es EE A HH Figure 4 CTU Simple Measure Type 1 front panel CtuWriteReadResults outputs the previous state of the following registers SCW PTEF RESA RESB RESC and these values are wired to an indicator on the front panel LabVIEW s I ndex Array function is used to pick out SCW which is passed to CtulnterpretScw This VI decodes SCW as measured back from the CTU
20. of 16 CTU LabVIEW VI User Guide W Cambridge IC 6 VI Descriptions The following table includes a list of VIs in alphabetical order and a description of each one For readability the highlighting conventions of section 1 5 have not been applied File name minus _ 2x vi AdapterClose AdapterConfigure AdapterGetl nfo Adapterl nternalReset AdapterOpen AdapterReadCharacters AdapterTest AdapterWriteCharacters AdapterWriteReadCharacters AnalyseMultiCtuResults BuildScwArray CalculatePositionStats CalculateStats CtuBuildPTEF CtuBuildSCW CtuChangeSysID CtuCheckSysID CtuConfigurelOs CtuConfigureMultiSensor PositionTriggers CtuConfigurePositionTriggers CtuDemo Description It is good practice to include this VI at the end of an application to close communications with the Adapter Configures the adapter Must be run after AdapterOpen and before any other Vis Included in QuickStart Retrieves Adapter and DLL version information Included in QuickStart Resets the Adapter itself Not normally required AdapterConfigure must be run afterwards for correct operation Opens communications with Adapter and creates an Adapter Reference see section 1 3 Included in QuickStart Communicates with the Adapter at a low level Not normally required Small application for testing communication with the Adapter on its own without a CTU chip attached See section 2 Communicates with t
21. olution improves by approximately 1 bit This VI is recommended for measuring CTU system performance so that systematic errors and noise can be treated separately It is also recommended for single sensor demonstration applications that do not need the maximum update rate of 100 per second CtuMeasureAndAnalyse is called by CtuRepeatAverage whose front panel is illustrated in Figure 6 and the block diagram in Figure 7 The design is similar to CtuSimpleMeasureTypel described in section 3 and the description below highlights only the main differences QuickStart is called at the start of execution to configure the CTU Adapter and CTU This time two additional controls are wired to the VI Multi CTU Support should be set to 0 if the system is configured normally with the CTU Adapter addressing a single CTU If an SPI Expander is attached set Multi CTU Support to 1 and CTU to Select to the appropriate CTU number Sensor Type is a front panel control whose value must match the type of sensor connected to the CTU s Sensor number input for correct operation Sin Length scales the position values reported by the CTU to physical units used for Position Average Position Std Dev and Position Pk Dev From Ave and Position results Its value should match the value quoted in the sensor s datasheet the value of Fine Pitch A in the case of Type 2 sensors CtuRepeatAverage_2x vi Front Panel on CambridgelC_CTU_Software_2x lvpr DAR File Edit View Projec
22. s active a boolean array with one entry per sensor which is TRUE for active and FALSE for inactive This VI determines the default states all active and the number of array entries the maximum number for the Sensor Type CtuWriteReadResults is called to collect the results of each measurement from each sensor It is called from within a for loop once for each entry in the Sensors active array each possible sensor It is also inside a case loop controlled by Sensors active so that it only runs if the selected sensor is active The outputs of CtuWriteReadResults are passed to either DisplayTypel1Results or DisplayType2Results for display depending on Sensor Type They are shown in Figure 9 These two VIs are configured to launch when CtuDemo is run right click on the VI in the block diagram click on SubVI Node Setup and select show front panel Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 8 of 16 CTU LabVIEW VI User Guide KCambridge IC when called The results of Type 1 sensor measurement are a 2D array 5 registers x 4 sensors while the results of Type 2 sensor measurement are a 1D array 8 registers x 1 sensor DisplayTypelResults includes a button array allowing the user to control which sensors are active and it passes this array back to CtuDemo to update the state of the Sensors active array accordingly Both display VIs also pass back the state of an alternative STOP button located on the
23. scaling factor from CTU units to physical units such as mm or degrees This VI also returns the states of active inactive buttons for each sensor which appear on its window DisplayType2Results Used by CtuDemo to display the results of a measurement of a Type 2 sensor see section 5 DisplayType3Results Used by CtuDemo to display the results of a measurement of a Type 3 sensor ErrorCodel nterpreter This VI interprets the numeric error code returned by CambridgelC DLL It is called by every VI that communicates directly with the Adapter using that DLL It is normally used together with LabVIEW s built in VI Error Cluster From Error Cod to signal an error to the application AdapterOpen is a typical example GetDateAndTime Used by SaveToFile to time and date stamp measurements GetLogo Retrieves logo image from file logo bmp HighestActiveSensor This VI is used by CtuDemo to work out which sensor s sample indicator to wait for See section 5 InterpretTypelResults This VI is used to interpret raw results register CTU contents for a Type 1 sensor It scales raw CTU position measurement into physical units such as mm or degrees using the Sin Length input parameter Usually called after CtuWriteReadRegisters to interpret results For example in CtuSimpleMeasureTypel see section 3 Also used for Type 4 sensors which have the same results register format as Type 1 Document part no 033 0008 0003 Cambridge Integrated Circuits
24. sheet incorrect Position noise different to that expected First few This is normal it can take up to 10 Consider using CtuMultiMeasureAndAnalyse to measurements with samples before the CTU locks on to collect position measurements This VI discards target in range are the target s frequency any initial invalid samples invalid Front panel controls The VI is consuming all of the PC s Add a time delay to the loop e g with unresponsive when CPU resources sitting in a loop PauseComms running Stop the VI change the control and run it again Other errors A VI has an unwired input and the Wire correct values to the VI s input default value is not appropriate Unknown LabVIEW error Try closing and re starting LabVIEW Unknown Adapter error Try unplugging the Adapter from the USB port and plugging it back in again Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 15 of 16 CTU LabVIEW VI User Guide W Cambridge IC 8 Document History Revision Date Description 0001 17 August 2009 First draft 0002 29 January 2010 Updated logo and style 0003 22 July 2010 Changed to reflect CTU Software version 2 x 9 Contact Information Cambridge Integrated Circuits Ltd 21 Sedley Taylor Road Cambridge CB2 8PW UK Tel 44 0 1223 413500 info cambridgeic com 10 Legal This document is 2009 2010 Cambridge Integrated Circuits Ltd CambridgelC I
25. t Operate Tools Window Help A an et Appicaton ront _ f 85 ie fee 5 al Bootloader V2 01 build 001 jon 133 170 bos TEE s feos8 187 51S ofl ofe l 38 BAH HHAH CambridgeI1C_CTU_Software_2x lvproj My Computer lt Figure 6 CTU Repeat Average front panel The Measurement statistics cluster contains some indicators that are specific to certain sensor types which are set to 0 when not applicable For example the CTU does not report Amplitude B or BA Position Mismatch values for a Type 1 sensor The Measurement statistics cluster includes Number of VALI D samples This will normally equal Requested Num VALID if a target is in range otherwise 0 Document part no 033 0008_0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 6 of 16 CTU LabVIEW VI User Guide Kcambridge IC CtuMeasureAndAnalyse also outputs individual processed measurements in the form of arrays once point for each CTU measurement Position results Amplitude results and Relative frequency results The indicators are hidden on the block diagram of Figure 6 but visible on the block diagram of Figure 7 Note that the time interval between individual measurements can be highly variable since it is based on PC timings CtuRepeatAverage_2x vi Block Diagram on CambridgelC_CTU_Software_2x lvproj My Computer File Edit View Project Operate Tools Window Help m Elk kalao eee toe Selected logo Gl 2009 2010 Cambridge a n Launch dow EER
26. t may not be reproduced in whole or part either in written or electronic form without the consent of CambridgelC This document is subject to change without notice It and the products described in it Products are supplied on an as is basis and no warranty as to their suitability for any particular purpose is either made or implied CambridgelC will not accept any claim for damages as a result of the failure of the Products The Products are not intended for use in medical applications or other applications where their failure might reasonably be expected to result in personal injury The publication of this document does not imply any license to use patents or other intellectual property rights Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 16 of 16
27. tailed in the relevant CTU chip datasheet 1 5 Document Conventions The names of VIs and DLLs are highlighted like this CTU Demo or to the name as it appears in the VI file name such as CtuDemo The suffix _2x is used in the full VI file name denotes version 2 x of the software This and the final vi in the file name is omitted for clarity The names of window controls and indicators are shown like this Next 1 6 Organisation of this Document The following main sections illustrate how to perform common tasks using the VIs supplied by CambridgelC for communicating with the CTU Designs become progressively more complex and later examples assume familiarity with earlier ones Section 6 includes a complete listing of the VIs provided together with a brief description Section 7 is a troubleshooting guide in case the system does not work as expected 1 7 Modifying CambridgelC VIs The example Vis below are intended to be modified to form the basis of a customer s own application It is strongly recommended that the CambridgelC Vis are not themselves modified however It is preferred to save as open an additional copy within LabVIEW to preserve the original examples In the more unlikely event that a sub VI requires modification it is also recommended to modify a separate copy and not the original Document part no 033 0008 0003 Cambridge Integrated Circuits Ltd 2009 2010 Page 2 of 16 CTU LabVIEW VI User Guide C
28. trolling the CTU s measurements on that sensor e g GO and single bit results e g VALID This VI converts an SCW value to a cluster representing each bit Used where SCW decoding is required e g CtuMultiWriteReadResults Takes a set of measurements and analyses them using AnalyseMultiCtuResults Used by CtuRepeatAverage see section 4 Calls CtuWriteReadResults multiple times to collect a set of results for a single sensor Discards invalid data Called by CtuMultiMeasureAndAnalyse Lists how many results to collect which differs by sensor type Called by CtuWriteReadResults The Adapter has a power supply output to the CTU This VI controls whether power is on or off Called by QuickStart Also called by AdapterTest see section 2 The Adapter has switchable pull ups for the CTU s SPI lines This VI controls whether they are active or not They should be set to active for correct operation unless pull ups are connected by another means QuickStart calls this VI and sets pull ups to active Also called by AdapterTest see section 2 This VI reads the state of the CTU s user 1O outputs For correct operation they must be set to digital e g with CtuConfigurelOs or pull up resistors should be fitted There are no switchable pull ups in the Adapter the pull ups controlled by CtuPullUpControl are the SPI interface lines only CtuReadlOs is called by CtuWaitForSamplel ndicator to read the CTU s user lOs without performing an S
29. which polarity to test for CtuWriteReadRegister This VI writes new data to the selected CTU register address It outputs the previous register contents NOT the newly written data It also returns the states of the CTU s user 10 pins Called by several VIs including CtuConfigurel Os CtuWriteReadRegisters This VI writes data to adjacent CTU registers starting at the specified address It outputs the previous contents of the registers NOT the newly written data It also returns the states of the CTU s user IO pins Called by CtuWriteReadResults CtuWriteReadResults This VI performs a write read SPI transaction to the selected sensor s SCW PTEF and results registers This single transaction can be used to read the most recent results form that sensor and to configure and kick off another measurement on the sensor It also manipulates the flags and enables present in the SCW and PTEF registers to control the CTU s user lOs Called by all Vis that perform measurements for example CtuSimpleMeasureTypel see section 3 CtuWriteReadS pi This VI performs an SPI write read in 16 bit word sized chunks It is not normally required since all CTU communication is register based and higher level Vis for register access such as CtuWriteReadRegisters are available DisplayTypel1Results Used by CtuDemo to display the results of measurement on up to 4 Type 1 sensors see section 5 Also used for Type 4 sensors The Sin Length parameter sets the
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