User Manual - Symmetric Research
Contents
1. void ParXchStop DEVHANDLE handle After successfully opening the device driver and initializing the PARxCH board the next step is to start acquisition by calling Start Until Start is called the ADS1210 A D converters are held in idle mode and do not sample their analog inputs Calling Start signals the converters to begin sampling their analog inputs and performing sigma delta conversion Once acquisition is started you can use the Ready function to identify when the PARxCH FIFO contains acquired data and the ReadData function to transfer that data over to the PC After you are done acquiring call the Stop function to put the ADS1210 converters back into idle mode and halt their execution Calling Stop is optional but if you do not the converters will continue executing until the Close function is called If you want to re start acquisition once the A D converters have been halted you should re initialize the PARxCH by first calling Close and Open before calling Start again This ensures that the A D converters on the board are in a known state so they will begin executing correctly 16 DLL LIBRARY SUPPORT READ DATA C usage include parxch h unsigned int ParXchReadData DEVHANDLE handle long Values unsigned int Nvalues int Error ReadData copies data from the PARxCH FIFO to the PC where it is available for further processing It also implicitly checks whether data2. sss 38 Application programs ees sesse see ee ee 9 C CMOS Setup sis taie fia tin Bets 3 OT Vert EE ee 11 D Dat file format 40 Data decies TERRE aed 11 EES IG 2e EE OR eet 11 Data Format ii ss Ee ees ED ee 28 39 Decimation eerte 28 Device driver InstallaHiOn esse esse see ee ee ee ee d Name uates 5 14 27 RemovValle 4 stick ch ots tone Bh Nee 4 DEE ESE eke heehee See Data Format BE GE castes 4 5 8 10 23 Diagnostic program See Diag LEET ceterae eei edle t 11 Digital I O Connecting iese esse ee ee ee ee Re 7 PUNCH ONS neuere epp 23 DriverName See Device driver name E ECP EPP BPP See Parallel Port Electrical Specs 38 ExtraDecimation eee 28 INDEX G Gainl Og EE hate 28 GPS EE RE N tiated 22 H Hardware installation 2 I IEEE 1284 See Parallel Port Installation ss ee ae Rede tee 2 Analog Connections seseseeseseeseseeeeee 6 Checklist iR anita 8 Device Driver 4 Digital VO Connections 7 Hardware sese 2 Software ien 4 Interrupts See Parallel Port Introduction trt 1 K Kernel mode driver See Device driver L LabView Support 32 LED Gd 2 8 Yellow sss 4 7 10 23 32 Library functions sss 12 ParXchAttachGps 22 ParXch
3. LD LIBRARYPATH LD LIBRARYPATH usr local sr parxch lib export LD LIBRARYPATH Finally note that the PARxCH requires exclusive access to the parallel port Do not daisy chain other physical devices or software drivers from the PARxCH port Under multitasking OS s these drivers can contend for the parallel port while the PARxCH is executing HP printer drivers are known to cause trouble in this regard Click on the HP printer driver dialog Exit button to disable it at run time Note While daisy chaining devices off the parallel port will not work it is perfectly fine to daisy chain power to other devices like the PARGPS as long as the total current draw does not exceed the wall transformer specs Included with the software are many readme txt files and source code files with comments We encourage you to refer to these for more information about the software INSTALLATION CONNECTING ANALOG INPUTS AND ANALOG GROUND To complete installation you will want to connect analog inputs to the PARxCH board and verify you are getting the correct values Inputs to the PARxCH are differential Differential inputs provide significant noise immunity over single ended inputs but also require some care to use them correctly The basics are as follows Access the analog inputs by connecting to the 25 pin D shell connector on the left hand side of the front panel The input pins are organized into pairs starting from the left of the connector wher
4. 21 GPS C usage include parxch h DLL LIBRARY SUPPORT void ParXchAttachGps DEVHANDLE handle DEVHANDLE GpsHandle int Error void ParXchReleaseGps DEVHANDL F handle The PARGPS board can be used to accurately time stamp data acquired by the PARxCH For the two boards to work together in this fashion both the boards and their drivers must be connected to one another The physical link is made by connecting the PPS signal from the PARGPS to digital input 3 on the PARxCH The software link between the drivers is made by calling the AttachGps function and passing in the handle to an opened PARGPS driver The ReleaseGps function should be called to clean up this software when it is no longer needed 22 DLL LIBRARY SUPPORT USER DIGITAL VO amp USER LED C usage include parxch h void ParXchUserlIoRd DEVHANDLE handle int Value void ParXchUserlIoWr DEVHANDLE handle int Value void ParXchUserLed DEVHANDLE handle int State The PARxCH board has user programmable digital I O with 4 input bits and 4 output bits that can be used to communicate signals to or from external equipment The physical signals are available on the 15 pin D shell connector on the right front of the enclosure or on the upper right edge of the PARxCH board An additional output bit is connected to the yellow LED To read the input bits call UserloRd To progr
5. When using dynamic linking make sure the parxch dll or parxch so library is on your Windows execution path or Linux LD_LIBRARY path so it can be found at run time 12 DLL LIBRARY SUPPORT The following is a discussion of each PARxCH library function Refer to the programs simp c and scope cpp for examples of how to use the library functions For a bare bones program demonstrating how to use the library refer to sample c in the examples directory 13 DLL LIBRARY SUPPORT OPEN AND CLOSE DEVICE C usage include parxch h DEVHANDLE ParXchOpen char DriverName int XchModel int PortMode double Sps double ActualSps int Error int ParXchClose DEVHANDLE handle The Open function opens the PARxCH device driver and provides a device handle that is passed to the remaining library functions It also initializes the PARxCH board using default values based on the requested sampling rate Open should be the first library function called It returns a valid device handle on success and the value BAD DEVHANDDLE otherwise If the optional Error argument is provided it is filled with an error code giving more detail about why the open failed See parxch h for a list of the possible error codes Pass NULL to ignore this parameter Open takes a few parameter that identify the specific driver and model and control some parallel port and ADS1210 A D converter features and can be used as a presence t
6. flashing as the graph is updated check the Use smooth updates box from the Edit gt Preferences gt Front Panel dialog To run this demo press the Run Arrow on the toolbar to enable the Driver Name control the Xch Model control the Port Mode switch and the Sample Rate dial Once these controls are set to their desired values press the green START button to begin acquisition Acquisition will continue until you press the red STOP button to end the demo 33 PARxCH Utility VIs LABVIEW SUPPORT The following table lists the utility VIs in parxch lIb and their arguments To allow complete flexibility in controlling the flow of execution dummy inputs and or outputs are provided for any function not having at least one input and output PARxCH Start is an example In Out Type Description input char Driver name PARxCH Open input int32 Xch Model Port mode PARICH PARACH etc 0 BPP 1 EPP 2 ECP BPP 3 ECP EPP Sampling rate Device handle 2 44 to 15625 native BAD_DEVHANDLE fail ADS1210 see BB spec sheet CrValue int32 Error code 0 to 21 see parxch h double True sample rate PARxCH Close input uint32 Device handle from Open output int32 Close result 1 ok 0 fail PARxCH Start input uint32 Device handle from Open output Int32 flow out Dummy PARxCH Stop input uint32 Device handle from Open output int32 flow_out Dummy PARxCH Rea
7. the PAR8CH provides a further improvement to the already accurate GPS time stamping available with the 1 and 4 channel units If both digital and GPS data are requested for the PAR8CH there will be 3 additional channels as described above However because the PARGPS PPS signal will be coming in on digital input 3 that line is no longer available for simple digital data So the corresponding bit is zeroed out in the returned digital channel As with the standard ReadData the optional Error parameter for all the variants will be filled with 0 if all is well and with an error code if something has gone wrong See parxch h for a list of the possible error codes You can ignore this parameter by passing NULL 20 DLL LIBRARY SUPPORT DATA READY OVERFLOW C usage include parxch h int ParXchReady DEVHANDLE handle int ParXchOverflow DEVHANDLE handle Once the PARxCH device driver is opened and execution has been started you can use Ready and Overflow to check whether the PARxCH FIFO is empty or full They can be polled in an infinite loop or with a timer tick Generally polling via a timer tick is preferred because that makes better use of the PC s CPU When the FIFO is empty Ready returns 0 Ready returns 1 as soon as any data is available in the FIFO Once all the data has been read out of the FIFO and transferred to the PC by calling ReadData Ready will again return 0 When acquiring at sampli
8. EPP mode check your CMOS setup Somewhere in the CMOS menus you will find an option for selecting the parallel port mode Typical CMOS parallel port options are SPP Standard Parallel Port mode bi directional IBM PS2 style bi directional parallel port mode EPP Enhanced Parallel Port mode ECP Enhanced Communications Port mode Chose EPP mode for use with the PARxCH EPP mode is backward compatible with SPP so you will be able to continue using other SPP peripherals you may have without reconfiguring your CMOS again If your CMOS does not have EPP mode then chose a bi directional mode if possible Usually the word bi directional will be included in the mode description although there is great variability from computer to computer We have even found computers that support bi directional mode when the CMOS is set to SPP The EPP and bi directional modes are also available indirectly as sub modes of ECP The sub modes for straight ECP and the common ECP EPP variation are often implemented differently from machine to machine So you should run the diagnostic program in the diags directory to verify which modes work on your machine for any given CMOS setting In addition you will want to set the parallel port address The SR software defaults to the IO address 0x378 Most users will already find their CMOS assignment set to this address Although the SR software can be used with other addresses we recommend using the 0x378 default INSTALL
9. PARxCH software also includes several other interesting programs These are briefly described below For more details than covered here refer to the readme txt files in the corresponding directories and comments in the source files simp This program is a simple console program for text based data acquisition and is located in the simple directory It is designed to be run from a command prompt and save data to an output file Simp is appropriate for applications divided between many windows where one window acquires data while other windows perform downstream processing The initialization parameters for simp are specified in the file simp ini Refer to inisyntx txt for details about its syntax and parameters scope This is a Windows GUI application and is located in the scope directory It displays data as horizontal traces on the screen in oscilloscope like fashion To start scope execute it from the Windows command line or the Windows Start menu Run command When the program is running you can select from menu commands to control the program features such as sampling rate output file names and display properties Besides using the scope menus you can also control the program features from an initialization file This file can be given on the command line when starting scope or read in from the Options menu after scope is running A default initialization file scope ini is FINISHED APPLICATIONS provided but you can also gene
10. and run the install batch script This will automatically unzip and create the default sr parxch or Linux usr local sr parxch directory structure on your hard disk We highly recommend you keep only one copy of the software on your hard disk and that you use the default directory structure This makes maintenance and installing upgrades easier See the readme txt files on the CD for more information For Win2000 XP and Linux installations besides copying the software to your hard disk you must also install a kernel mode device driver Administrator or root permissions are required for this step but once the driver is installed ordinary users can use it freely To install the kernel mode device driver change to the PARxCH driver subdirectory on your hard disk and run the indriver program with no arguments to see a list of valid driver names Then run indriver again with the name of driver associated with the parallel port you are using You can remove the device driver using this name and the rmdriver program For example to install the driver on LPT1 at address 0x378 and interrupt 7 with the PARSCH as the default model use gt indriver PAR8CH 0x378 7 To remove it use gt rmdriver SrParXch0 INSTALLATION If you forget the exact assigned device driver name you can find it using the showdriver utility or on a list of installed drivers provided by the OS For Win2000 XP use the Device Manager and look under the SR Instrumentation
11. effective sampling rate that is unacceptable for the ADS1210 ExtraDecimation sets the amount of decimation done by the device driver in addition to the native decimation done in the A D converters themselves and affects the effective sampling rate Use the SpsGainToTde helper function to compute the values of turbolog decimation and extradecimation corresponding to a particular sampling rate FullOpen will fail if you specify an effective sampling rate that is unacceptable for the ADS1210 Unused is not used at this time but is included to allow for future improvements without causing a change in the function prototype If ADS1210 converters are successfully initialized the ADS1210_CrValue parameter will be filled with the readback value from the ADS1210 control register Besides checking the FullOpen return you can also check the bits in this value to make sure all ADS1210 control register values were written out and read back successfully Pass NULL to ignore this parameter 28 DLL LIBRARY SUPPORT Besides returning a device handle FullOpen also fills the Error parameter with an error code indicating success or why it failed See parxch h for a list of the possible error codes Pass NULL to ignore this parameter 29 DLL LIBRARY SUPPORT A typical calling sequence for FullOpen would be include parxch h DriverName PARXCH 0 XchModel PARXCH MODEL PARACH PortMode PARXC
12. is ready before reading and whether overflow or bad on board voltage has occurred Because of these checks ReadData may be the only function you need besides Open Close and Start Stop To use ReadData you need an array to hold the data values and the dimension of that array Nvalues ReadData reads as many data points as possible into that array up to Nvalues It returns the number of points actually read This will always be a multiple of the number of analog channels x but may be zero if no complete data values are ready yet To read a single point for each channel just pass 1 4 or 8 for Nvalues as appropriate The optional Error parameter will be filled with O if all is well and with an error code if something has gone wrong See parxch h for a list of the possible error codes You can ignore this parameter by passing NULL How is the data returned by ReadData organized Values are returned in multiplexed fashion When using the PAR8CH for example the first value from channel 0 will be in Values 0 the first value from channel 1 in Values 1 and so on The second converted value from channel 0 will be in Values 8 where in general the value from the nth conversion on channel c will be given by Value at nth conversion from channel c Values n 8 c Each 24 bit A D value is stored as a long 32 bit integer The format of this number is a standard 32 bit two s compliment signed value unless you request an unsigned offset binary va
13. returned by the A Ds The value of this parameter should be 0 for signed integer or for unsigned offset GainLog controls the internal ADS1210 programmable gain amplifiers and maps into the gain bits in the ADS1210 control register This is an encoded value and not the gain setting itself Use the defined constants in parxch h to set this value While the ADS1210 does have programmable gain it gives the best performance with a gain of 1 GainLog 0 Most applications are best served by using a gain of 1 and then shifting the digital values left to provide a software gain TurboLog maps into the turbo bits in the ADS1210 command register controls the internal ADS1210 modulator and affects the resolution Use the SpsGainToTde helper function to compute the values of turbolog decimation and extradecimation corresponding to a particular sampling rate FullOpen will fail if you specify a sampling rate that is unacceptable for the ADS1210 Also increasing the gain reduces the available turbo options since the product of gain and turbo is fixed For best performance use the maximum turbo value TurboLog 4 Decimation maps into the decimation bits in the ADS1210 control register sets the decimation value for the A D converters and affects the native sampling rate Use the SpsGainToTde helper function to compute the values of turbolog decimation and extradecimation corresponding to a particular sampling rate FullOpen will fail if you specify an
14. ATION Users with PC s manufactured before 1995 or lacking EPP BPP compatible parallel ports may wish to consider installing an Enhanced IO card in their ISA bus These cards are available at many computer stores Check to make sure the card has IEEE 1284 compatibility If it does it will support EPP mode These cards are inexpensive usually 40 or less SR can also supply these cards if you need one If you use an Enhanced IO card in your PC you will probably have to configure it for EPP mode by setting jumpers on the card rather than your CMOS Refer to the documentation that came with the card Also configure the add in card for base address 0x378 if possible So how do you verify if the PC s EPP port is communicating with the PARxCH board correctly After installing the software run the diag program in the diags directory giving std as the command line option This will automatically check to see if a PARxCH board is properly connected and let you twiddle the front panel yellow LED If diag succeeds and the yellow LED toggles you are correctly connected to the PC SOFTWARE INSTALLATION A CD ROM is included with the PARxCH Software for each supported operating system can be found in the respective directory Each OS subdirectory includes a readme txt file a compressed PKZIP or Linux gzipped tar format file and an installation batch or script file To install the PARxCH software change to the OS subdirectory appropriate for your computer
15. Cl Sse e EE EE ehe 14 ParXchFullOpen 27 ParXchGetRev sss 26 ParXchInterruptDisable 24 ParXchInterruptEnable 24 ParXchOpen eee 14 Par SchChverflow 21 ParXchReadData 17 ParXchReadDataAll 19 ParXchReadDataWithDigital 19 ParXchReadDataWithGpsMark 19 ParXchReady sss 21 ParXchReleaseGps 22 ParXchSpsGainToTde 31 ParXchS tart iese ee NEEN 16 ParXChStOp ete tente 16 ParXchTdeToSpsGain 31 ParXchUserIoRd 23 ParXchUserIoWir ssss 23 ParXchUserLed 23 ParXchVoltageGood 25 Library path setting sss 5 M ro EE 10 Model EE See Xch Model O Offset data Tomat 39 Out file format ee ee ee 40 OUIZAS Craik eee ase A ca Bnet 11 Out2sud iese ee ee ee Re ee ee 11 P Parallel Port Connecting ere 3 Daisy Chaining eee 5 Interrupts isi nonno EE We ed 24 Mode 3 14 27 PARGPBS Ee EE E 22 PortMode See Parallel Port Power supply Connecting essere 2 Requirements sees 38 S Sample tee ette 10 Sampling rate 14 21 28 31 Sca
16. DLE handle long Values unsigned int Nvalues int Error In addition to the standard ReadData function which copies the acquired analog data from the PARxCH FIFO to the PC there are three variants which provide additional data While the argument list is identical for all the read data functions the size of the Values array will differ and must be large enough to hold all the data being requested Because of additional firmware enhancements beyond those found in the 1 and 4 channel units the PAR8CH can record the values of the digital inputs when each analog sample is ready Requesting this digital data adds one additional channel beyond the 8 analog channels The low 4 bits of this additional 32 bit integer channel contain the values of the 4 digital input lines sampled when the related analog data is ready Requesting GPS data adds one additional channel beyond the 1 4 or 8 analog channels This additional channel contains the PPS event number often referred to as the GPS mark which is used to correlate the PPS with its associated serial NMEA data For the PAR8CH requesting GPS data also adds a second additional channel containing the results of an on board counter This on board counter records the number of 800ns counts between the time the PPS signal arrives and the time when the next analog data sample is ready Because this 19 DLL LIBRARY SUPPORT counter is unaffected by interrupt latencies in the OS
17. H PORT MODE EPP Df PARXCH DF SIGNED Sps 50 0 GainLog PARXCH_GAIN_1 ParXchSpsGainToTde Sps GainLog amp TurboLog amp Decimation amp ExtraDecimation handle ParXchFullOpen DriverName XchModel PortMode Df GainLog TurboLog Decimation ExtraDecimation ULL ULL if handle BAD DEVHANDLE printf error unable to initialize 30 DLL LIBRARY SUPPORT ADVANCED FUNCTIONS SPS HELPERS C usage include parxch h void ParXchSpsGainToTde double Sps int GainLog int TurboLog int Decimation int ExtraDecimation void ParXchTdeToSpsGain int TurboLog int Decimation int ExtraDecimation double Sps int GainLog The SpsGainToTde and TdeToSpsGain functions convert between the related parameters of sampling rate gain turbo rate native decimation and extra decimation For a description of the different parameters please refer to the Advanced Functions FullOpen section above A typical calling sequence for SpsGainToTde and TdeToSpsGain would be include parxch h Sps 200 0 ParXchSpsGainToTde Sps PARXCH GAIN 1 amp tl amp dec amp exdec ParXchTdeToSpsGain tl dec exdec amp ActualSps amp ActualGL printf Requested Sps f n Sps printf Actual Sps f n ActualSps 31 LABVIEW SUPPORT LABVIEW SUPPORT Support for National Instruments LabView is provided in the LabView LLB VI library parxch llb in the la
18. PARxCH User s Guide Manual Release 01 30 07 Copyright c Symmetric Research 2007 Web www symres com WARRANTY LIMITED WARRANTY WHAT IS COVERED Symmetric Research warrants its PARxCH product will be free from defects in workmanship and materials for one year from the date of original purchase WHAT SR WILL DO Symmetric Research will repair or replace defective PARxCH systems covered under this warranty at no cost to the customer other than shipping The customer is responsible for shipping to SR manufacturing facilities WHAT IS NOT COVERED Symmetric Research does not warrant the PARxCH product for use with customer provided power supplies or analog input voltages outside the range of values listed in this manual Incorrectly connecting power or analog inputs may permanently damage the system Furthermore PARxCH systems that have been customer modified including but not limited to changes to the analog input voltage range circuitry are also not covered under this warranty Symmetric Research will at its discretion determine when any returned equipment has been run from incorrect power supplies incorrect analog inputs or without AGND connected and is not covered by the terms of this warranty Symmetric Research is not liable for any loss damage or inconvenience including direct special incidental or consequential damages resulting from the use or inability to use the PARxCH product TABLE OF CONTEN
19. TS Chapter 1 Introduction sig sain audi daha banana sad cassava 1 Chapter 2 Installation GO iet OE EE Ed 2 Chapter 3 Finished Applications and Other Programs 9 Chapter 4 Library Functions se se ee se Ge ee Gee Ge nennen nennen ene 12 Chapter 5 LabView Support SSES CU deerat 32 Appendix A Electrical Specs NENNEN 38 Appendix B Data Format NEEN 39 Appendix C Output File Formats se se ese se ee ge ee Ge Ge enne 40 INTRODUCTION INTRODUCTION The Symmetric Research PARxCH family of 24 bit A D data acquisition systems are designed for acquiring high resolution data on the PC at sampling rates from DC to several kHz The x in the product name represents the number of analog channels and can be 1 4 or 8 In addition to the analog channels these A D boards can also acquire one bit of information from each of 4 digital channels Connecting to the PC parallel port the PARxCH sits outside the PC in its own vinyl covered steel enclosure for quiet noise free operation Because it interfaces to the parallel port the system is easy to use with closed PCs such as laptops Based on the Burr Brown ADS1210 24 bit sigma delta A D converter the PARxCH has an individual converter per channel architecture This minimizes channel cross talk skew and settling time You get the full performance of a dedicated A D converter on each channel The AS1210 converters are instrument grad
20. allel port s Parallel Error pin and is active low When the PARxCH is not properly receiving power from the wall transformer it does not have any power available to drive the voltage good signal high to indicate the bad voltage In this situation it relies on the PC having a pull up resistor for this pin so floating inputs are brought high Most PC s include this pull up but some do not You may wish to add a pull up to your computer if that is the case 25 DLL LIBRARY SUPPORT LIBRARY REV C usage include parxch h void ParXchGetRev int Rev GetRev fills the Rev argument with an integer representing the current revision number of the parxch library For example a value of 201 indicates version 2 01 26 DLL LIBRARY SUPPORT ADVANCED FUNCTIONS FULLOPEN C usage include parxch h DEVHANDLE ParXchFullOpen char DriverName int XchModel int PortMode int Df int GainLog int TurboLog int Decimation int ExtraDecimation int Unused long ADS1210_CrValue int Error FullOpen opens the PARxCH device driver and initializes the PARxCH board while allowing advanced users more control over the initialization parameters than the simpler Open FullOpen returns a valid device handle on success and the value BAD DEVHANDLE otherwise If the optional Error argument is provided it is filled with an error code giving more detail about why the open failed FullOpen takes several pa
21. am the output bits call UserloWr with the desired output value Call UserLed with 1 to turn the yellow LED on and with 0 to turn it off Before these functions will work Open must be called to open the PARxCH device driver and initialize the parallel port In addition to digital input the inverted value of bit 3 is mapped to the parallel port interrupt Enable or disable this function with the InterruptEnable and InterruptDisable functions discussed below See diag c in the diags directory for an example of how to use UserLed 23 DLL LIBRARY SUPPORT PC INTERRUPT C usage include parxch h void ParXchInterruptEnable DEVHANDLE handle void ParXchInterruptDisable DEVHANDLE handle The PC can be interrupted by sending a signal over the parallel port These functions enable and disable this capability Before these functions will work Open must be called to open the PARxCH device driver and initialize the parallel port 24 DLL LIBRARY SUPPORT VOLTAGE GOOD C usage include parxch h int ParXchVoltageGood DEVHANDLE handle VoltageGood returns 1 if the voltage on the PARxCH board is good within 196 of 4 75 volts It returns 0 otherwise Open must be called to open the device driver and initialize the parallel port before this function will work The VoltageGood function reports the state of the voltage good signal This signal is sent from the PARxCH board via the par
22. bview directory This LLB contains 3 application and 20 utility VIs The application VIs include complete data acquisition programs that rely on the underlying utility VIs which are wrappers around the corresponding core parxch dll DLL functions supplying the low level support for all SR PARXCH software To use the PARxCH LLB library put sr parxch lib on your path so Windows can find the core DLL at run time You can then access the VIs by using the File gt Open menu option to open sr parxch labview parxch llb If it is more convenient to have those VIs available from the User Libraries button on the Function Palette you can do this using the Edit gt Edit Control amp Function Palettes menu option or by copying parxch llb into the user lib subdirectory of your LabView directory For further details please refer to file sr parxch labview readme txt The PARXCH application VIs are described below For additional information please refer to the descriptions of the underlying DLL functions or use the Window gt Show VI Info menu option to access the information stored within each VI itself The VIs have been saved unlocked with their block diagrams included so you can modify them as needed to fit your application PARxCH LED Demo This VI is so simple it does not even start acquisition It just initializes the PARxCH and allows you to toggle the on board yellow LED to visually verify that initialization was successful To run the demo
23. circuit then it will likely drift with time and pin the A D converters A system that is initially working may appear to start failing This condition usually does not cause permanent damage Connecting the PARxCH analog ground pins to your input analog ground reference will avoid this Note that simply connecting the input of a PARxCH channel to your analog ground will work but essentially turns the differential inputs into single ended The full scale analog input voltage range of the PARxCH is 10v This means that if the pin is at 10v and the pin is at 10 volts for a total difference of 20v you will record the full positive counts The full negative counts are recorded when the situation is reversed with 10v on the pin and 10v on the minus This means the 2 24 possible digital counts are spread over a range of 40 volts which results in a scale factor of roughly 420 000 counts per volt or about 2 microvolts per count The system will survive modest overvoltages without any damage but overvoltage conditions should be avoided For example do not INSTALLATION apply a static shock to the analog input pins Symmetric Research reserves the right to determine when systems have been damaged by excessive overvoltage See the warranty page at the beginning of this manual Finally note that any analog inputs left floating tend to be susceptible to noise When doing tests for channel resolution or simply to suppress noise short unu
24. dy input uint32 Device handle from Open output int32 Ready result 1 ready 0 not PARxCH Overflow input uint32 Device handle from Open output int32 Overflow result 1 overflow 0 not input uint32 Device handle PARxCH Read Data input input int32 uint32 Data values in Nvalues input output int32 int32 Error in Read Data result max number to read output int32 Data values values read array of int32 values 34 output int32 LABVIEW SUPPORT Error 0 to 21 see parxch h input uint32 Device handle PARxCH User Led input output int32 int32 from Open Oor 1 Dummy User Led flow_out input uint32 Device handle PARxCH User IO Wr Value input output int32 int32 from Open 0x0 to OxF flow out Dummy input uint32 Device handle PARxCH User IO Rd int32 Value in input output int32 Value 0x0 to OxF PARxCH Interrupt Enable uint32 Device handle from Open int32 flow_out Dummy PARxCH Interrupt Disable input uint32 Device handle from Open output flow_out Dummy input Driver Name PARxCH Full Open input PAR4CH PARSCH etc 0 BPP 1 EPP 2 ECP BPP 3 ECP EPP Xch Model Port mode int32 2 44 to 15625 native 0 signed offset Sampling rate Data Format int32 int32 Gain log Turb
25. e meaning they maintain full accuracy right down to DC In addition data from the A D converters is buffered with a deep 2Mb memory array on the PARxCH This allows for continuous data acquisition even with long PC task switching latencies Software that comes with the board has both high level finished applications ready for immediate use and low level function libraries for those wishing to do custom programming Support is provided for DOS Win9x Win2000 XP Linux and LabView The Win2000 XP and Linux software features true kernel mode drivers for good performance and reliable operation Other items included with the system are a 9vdc wall transformer a cable for connecting to the PC parallel port an analog input terminal board and circuit diagrams Everything needed to be up and running right away We hope you enjoy using the SR PARxCH INSTALLATION INSTALLATION Installation of the PARxCH is straightforward You ll need to plug in the wall transformer connect to the PC parallel port install the software and provide suitable analog inputs The individual steps in more detail are CONNECTING POWER The PARXCH requires power independently of the PC Included with the system is a 9vdc wall transformer This wall transformer should be plugged into a 110vac wall socket and the 9vdc connector plugged into either of the two power jacks on the back of the PARxCH The second power jack is available for daisy chaining power to optional
26. e left Be careful to avoid static discharges when touching the analog input pins Try out the simp and scope programs to acquire some data and see the system work If you are using dynamically linked libraries make sure the sr parxch lib directory is on your execution path or Linux LD LIBRARY path so parxch dll or parxch so can be found at run time Connect an analog ground from your source devices to the analog ground pins on the analog input D shell connector Even though the PARxCH inputs are differential they still require an analog ground reference to avoid clipping Do not touch the PARxCH analog input circuitry while in use Your body has voltages that will easily corrupt 24 bit accuracy Short out any channels not in use Floating channels are susceptible to noise FINISHED APPLICATIONS FINISHED APPLICATIONS SIMP SCOPE AND OTHER PROGRAMS The SR PARxCH comes with finished application programs you can run immediately after installing the system These programs will help you become more familiar with the system and may also fill your entire acquisition needs The source code is included for those wanting to modify these programs for custom applications The simp and scope programs have both been written in C Simp is a simple text only command line program while scope has a full Windows GUI graphical interface and display Under Linux only the simp program is available In addition to these basic data acquisition programs the
27. e the signal pairs are grouped on the connector For the PARICH channel 0 is on pins 1 6 For the PAR4CH channels 0 to 3 are on pins 1 9 2 10 3 11 4 12 respectively For the PAR8CH channels 0 to 7 are on pins 1 14 2 15 3 16 4 17 5 18 6 19 7 20 8 21 respectively The remaining pins are analog ground Quick reference information is also printed on the label on the bottom of the PARxCH enclosure To make simple wire connections to the analog inputs you may wish to use the TRMISE or TRMxxV terminal board included with the system Note that the numbers listed along the screw edge of the terminal board are not the same as the D shell pin numbers The terminal board is numbered so that screws 1 2 are channel 0 4 etc A number of other analog input connector options such as solder cup D shells are also available from SR The A D converters return a count which is proportional to the difference in voltage between the and input pins However they can only do this within limits If the absolute common mode voltage is too high then the converters will be beyond their specifications To maintain a common analog ground you must connect at least one of the analog ground pins to your analog ground reference The analog ground pins are 2 5 and 7 9 for the PARICH 5 8 and 13 15 for the PAR4CH and 9 13 and 22 25 for the PAR8CH If the analog ground of the PARxCH is floating with respect to the analog ground of your input
28. eatures of interacting with the PARxCH For full featured acquisition see the simp program in the simple directory meter This is a command line text only data acquisition program that demonstrates one way to use the PARxCH at slower sampling rates It is located in the meter directory and includes comments describing how to determine the channel offsets for use in a calibrated system For LabView users there is a finished meter like program with a graphical interface Refer to the following LabView chapter for more information 10 FINISHED APPLICATIONS 2task Multitasking systems such as Windows and Linux allow several tasks or programs to run at the same time The 2task directory includes a demo batch or script file that shows how to run the simp acquisition program while simultaneously running a downstream processing program to perform some additional functions on the acquired data Under Linux the acquisition task is run in the background and the processing task is run in the foreground While under Windows both tasks are run in separate windows digio This is a command line text only program that lets you test the digital I O See the comments at the top of the source file for information on how to set up a simple loopback test jig using a terminal board and a few wires Conversion programs out2asc dat2asc out2sud dat2sud etc The convert directory has several subdirectories that contain programs for converting the o
29. equipment such as the PARGPS time stamping unit Many of our international customers will have been provided with a 220vac wall transformer Refer to the label on the wall transformer for compatibility with your local wall power Once plugged in you can verify the wall transformer is on by checking the right hand side green LED near the power connector on the back of the PARxCH If it is on your wall transformer is plugged in and powered on The left hand side green LED on the back of the PARxCH near the DB25 parallel port connector indicates whether the PC has sent a power up or power down signal to the PARxCH In its power down mode the PARxCH draws very little current This can be useful for applications requiring only occasional data acquisition helping to preserve the life of field batteries etc Turning off your PC will also automatically power down the PARxCH The PARxCH can be powered with a wide range of wall transformers Any AC or DC wall transformer with a voltage between 9 and 24 volts is acceptable as long as it has a 2 1mm center plus plug If you have a choice chose a voltage nearer to 9 volts rather than 24 Running at lower power supply voltages will reduce the heat dissipation of the internal regulators If you are running the PARxCH outside of its enclosure in a PC104 application you can also use the alternative power connector The exact style and location of this connector depends on which of the PARxCH boards you are
30. est for the PARxCH in addition to initializing it Advanced users wanting more control over the ADS1210 parameters can use the FullOpen function discussed later in the Advanced Functions FullOpen section The DriverName parameter identifies the device driver and therefore the parallel port base VO address The XchModel parameter identifies which member of the PARxCH family is being used the PARICH PAR4CH or PAR8CH The PortMode parameter controls the parallel port mode that the parxch library will use in communicating with the board Usually DriverName is SrParXchO and PortMode is 0 to 3 indicating PS2 style bi directional EPP ECP BPP or ECP EPP communications respectively Use the defined constants in parxch h to specify these parameters and refer to the installation chapter of this manual for more information about parallel port settings The Sps parameter is the desired number of samples per second Because of how the A D converters work not all sampling rates can be achieved Open selects the closest achievable rate and returns that value in the parameter ActualSps 14 DLL LIBRARY SUPPORT The Close function cleanly shutdowns the device driver It should be the last library function called In some cases it may be called implicitly at program termination However you should not rely on this 15 DLL LIBRARY SUPPORT START AND STOP EXECUTION C usage include parxch h void ParXchStart DEVHANDLE handle
31. gned 32 bit values When offset format is selected the data is treated as unsigned two s complement Selected values for both formats are shown in the following table Offset Signed Lowest value 0x00000000 OxFF800000 Mid level minus one OxOO7FFFFF OxFFFFFFFF Mid level zero 0x00800000 0x00000000 Highest value OxOOFFFFFF OxOO7FFFFF 39 DATA CODING FORMATS APPENDIX C OUTPUT FILE FORMATS The acquisition programs simp and scope can output the acquired data to files in one of two formats out files and dat files Additional utility programs located in the convert directory are available for converting the binary out and dat data files into other formats such as ASCII text or IASPEI SUDS The out file format is very simple and contains only the multiplexed data values stored as 32 bit integers The data is organized exactly as described for the ReadData function The first integer contains the data for point 0 of channel 0 The second has the data for point 0 of channel 1 The Nth integer has the data for point 0 of channel N while integer N 1 has the data for point 1 of channel 0 And so on All data is written out in the standard little endian PC byte order where the low byte is written first When out files are requested the simp and scope acquisition programs also write a single separate header file with the hdr extension This file contains information such as sampling rate and number of channels t
32. group For Linux run sbin lsmod For additional information on installing the device driver please refer to the readme txt file in the driver subdirectory If you have the PARxCH powered on and connected to your PC s parallel port you can verify correct operation by running the diag program located in the diags directory This program is designed to be run from a command prompt Follow the on screen messages for more information For programmers the core part of the software supplied with the system is a collection of low level functions that are required to communicate with the PARxCH For the 32 bit Windows systems these functions can be linked in statically or used dynamically from the Dynamic Link Library parxch dll Programs that use parxch dll dynamically must be able to find it at run time or Windows will give an error message The best way to inform the system of the location of parxch dll is to add its location to your execution path The following command can either be executed from the command line or added to your autoexec bat file gt set path path sr parxch lib For Linux systems the core low level functions can also be linked in statically or used dynamically from the shared library parxch so Programs using the shared library dynamically should set the LD LIBRARYPATH environment variable so the library can be found at runtime One way to do this is by executing the following command line or adding it to your profile file
33. has been initialized call Start to begin acquisition Then use ReadData to move the data from the PARxCH FIFO into a PC memory array after which it can be displayed or saved to the hard disk Also the Ready function can be used to determine when the PARxCH contains at least one point of acquired data When you are done call Stop and Close to stop acquiring data and close the driver There are generally two schemes for determining when to call ReadData The first is infinite loop polling While easy to program this method wastes considerable PC horsepower A better way is to set up a PC timer tick that calls ReadData in about the time the PARxCH takes to acquire the amount of data you want to read This method greatly reduces the number of PC cycles used in polling and fits in well with the multitasking capabilities of Windows or Linux It is also possible to have the PARxCH interrupt the PC when the FIFO is ready with data Generally there is little improvement in performance using interrupts over a timer tick Interrupts are considerably more difficult to use with Windows than timer ticks and we generally recommend using a timer tick in most applications When using the parxch library functions be sure to include the header file parxch h in any C source code The prototypes in this file make sure the correct parameters are passed to the functions You will also find the defined constants in parxch h useful for making your programs more readable
34. hat apply to all the out data files The format of this header file can be seen by looking at the HDR_data structure in the simp h file in the simple directory The dat file format is more complicated as each file contains a 4096 byte header followed by data records possibly of many different types The header begins with SrDatHdrLayout structure defined and described in the srdat h file in the include directory The remaining bytes of the header are padded with zero Each data record is composed of a short 128 byte record tag structure identifying the format and size of the following data and then the data itself The record tag structure and the currently defined data formats are described in the srdat h file The dat file header and data records are written out in standard little endian PC byte order Which data format is best That depends on what you need Most users will be happiest with the dat format since that keeps all the header information tightly associated with the data and allows saving GPS PPS and serial data in addition to the analog and digital data But these extra features do have a cost in terms of speed and complexity So users with high sampling rates that only need analog and digital data may prefer using the simpler out file format 40 INDEX 2 task Re Re oe Da re Re 11 A Analog Ground connecting 6 8 38 Analog Inputs Connecting amener URS 6 Full scale eer 6 Maximum voltage
35. le factor Counts per vote 6 SCOPE i inteso Re es 9 Signed data format esse se se see se ee 39 el EE 9 INDEX Software mstallapon 4 SPS Heater estt outs wee See Sampling rate T du GA EE 6 7 RA ELS inane 7 TRMXXV esse ee eres 6 TUDOLOS SES RED hus sinks 28 V VIEWS EREGAS AG AG GR e RES 10 X Xch Model 14 27 42
36. lue by setting the df parameter in the advanced FullOpen function See the Advanced Functions FullOpen section for a discussion of the df parameter and Appendix B for more details on the possible data formats 17 DLL LIBRARY SUPPORT A typical code fragment for using ReadData would be Declare an array to contain acquired values Values long malloc Nvalues sizeof long Open driver and start execution Acquire and process data while 1 Nremain Nvalues NextPt 0 Get Nvalues worth of data while Nremain gt 0 Newpts ParXchReadData handle amp Values NextPt Nremain amp Err Nremain Newpts NextPt Newpts Check for FIFO overflow and other errors if Err PARXCH ERROR NONE Error Error sWMn PARXCH ERROR MSG Err Do something with data SaveValuesToDisk Values See sample c in the examples directory and simp c in the simple directory for complete code listings showing how to use this function 18 DLL LIBRARY SUPPORT READ DATA WITH DIGITAL AND OR GPS C usage include parxch h unsigned int ParXchReadDataWithDigital DEVHANDLE handle long Values unsigned int Nvalues int Error unsigned int ParXchReadDataWithGpsMark DEVHANDLE handle long Values unsigned int Nvalues DAE Error unsigned int ParXchReadDataAll DEVHAN
37. nel title 0 1 2 3 4 5 6 7 default 1 4 8 12 char 36 Sample rate LABVIEW SUPPORT Gain Filter coeff 2 44 to 15625 native 0 gt 2 0 to 4 gt 2 4 Filter scale 0 1 error Error out PARxCH Write Data File File name Scope out input error Wave array Error in Acquired data values output error Error out 37 ELECTRICAL SPECS APPENDIX A ELECTRICAL SPECS POWER SUPPLY REQUIREMENTS The PARxCH uses 5vdc to power the analog and digital circuitry The on board voltages are generated by linear regulators from the off board power supply usually a wall transformer to provide quiet operation The off board power supply must allow enough voltage headroom for the on board regulators to operate Off board power of at least 10 volts is recommended for reliable operation The system requires approximately 120ma of current This figure is approximate because the actual current draw depends on the sampling rate Higher sampling rates result in more current draw We have found 120ma to be a typical maximum figure A 9vdc 500ma wall transformer is supplied with the system When loaded at 120ma it will provide approximately 12vdc of output power more than enough to adequately power the PARxCH Other off board power supplies are acceptable AC power will be rectified by the on board circuitry and 9vac wall or chassis mount transformers are perfectly fine with no deg
38. ng rates lower than about 40 Hz it may be easiest to use the implicit ready check inside ReadData rather than calling Ready explicitly The reason is that extra averaging beyond that in the converters themselves is done in the device driver software to ensure high resolution below 40 Hz ReadData will return O until it is able to read a complete averaged data point but Ready will return 1 as soon as a single raw data point is in the FIFO You may also want to check for the PARxCH FIFO overflowing If you wait too long before calling ReadData it is possible for the FIFO buffering to be exceeded and data lost The PARxCH buffer is actually 2Mb in size 4Mb for the PARSCH Depending on the sampling rate you can wait a long time before an overflow will occur When the FIFO is empty or partially filled all is ok and Overflow returns a 0 Once the FIFO becomes full Overflow returns 1 and latches this information until the FIFO is reset This means that once an overflow has occurred you can call ReadData to download the valid data currently in the FIFO However any additional data arriving after the overflow would be corrupt so it is discarded and Overflow continues to return 1 even though the FIFO may no longer be full To re initialize the PARxCH and reset the FIFO call Stop Close Open and Start The programs meter in the meter directory and simp in the simple directory show how to use these functions while getting data from the PARxCH board
39. o log 0 to 4 for 1 to 16 int32 int32 0 to 4 for 1 to 16 19 to 8000 1 default Decimation ExtraDecimation uint32 BAD_DEVHANDLE fail See BB spec sheet Device handle ADS1210 CrValue double Error code True sample rate 0 to 21 see parxch h 35 PARxCH Sps Gain To Tde double Samples sec LABVIEW SUPPORT 2 44 to 15625 native int32 Gain log Turbo log in 0to4 Decimation in ExtraDecimation in Turbo log Decimation ExtraDecimation 19 to 8000 1 default PARxCH Tde To Sps Gain input int32 int32 Turbo log Decimation 0to4 19 to 8000 int32 double ExtraDecimation Samples sec in 1 default int32 double Gain log in Samples sec 2 44 to 15625 native int32 0to4 Gain log PARxCH Voltage Good input output uint32 int32 Device handle Voltage result from Open 1 good 0 bad PARxCH Get Rev input int32 Revin output int32 Rev result 201 means DLL rev 2 01 PARxCH Fifo Ready Size input uint32 Nvalues in output uint32 Nvalues Currently always 1 4 PARxCH Write Header File Data format 0 signed offset int32 Word size Record pts 4 int32 path Channels File name Nvalues 1 4 8 string error Id Error in Scope hdr SR PARxCH input int32 string Channel array Chan
40. radation in system noise or resolution MAXIMUM ANALOG INPUT VOLTAGE RANGE The absolute maximum analog input voltage range of the PARxCH is 10v This is mapped by the on board circuitry to a 0 to 5v range that is compatible with the ADS1210 A D converters Although the PARxCH analog inputs are protected by resistive current limiting do not exceed the recommended 10v input range or you may damage the system Static discharges near the analog input pins should also be avoided All of the PARxCH analog inputs are differential This means that the absolute difference between the and inputs on any given channel must be less than 20 volts In addition for the system to work correctly you must establish a common analog ground that is connected to one of the ground pins on the analog input D shell connector The inputs are differential only up to the point where the A D converters are pinned When analog ground floats it can easily drift to absolute voltages that exceed the A Ds common mode range even though the absolute difference is still within range Connecting an analog ground reference avoids this 38 DATA CODING FORMATS APPENDIX B DATA FORMATS When programming the PARxCH you can use the Data Format parameter df to choose the format of the acquired data The two choices are signed and offset The Open function defaults to the signed format When signed format is selected the 24 bit data is sign extended and treated as si
41. rameters controlling various parallel port and ADS1210 A D converter features and can be used as a presence test for the PARxCH in addition to initializing it The DriverName parameter identifies the device driver and therefore the parallel port base I O address The XchModel parameter identifies which model or member of the PARxCH family is being used the PARICH PAR4CH or PAR8CH The PortMode parameter controls the parallel port mode that the parxch library will use in communicating with the board Usually PortName is SrParXchO and PortMode is 0 to 3 indicating PS2 style bi directional EPP ECP BPP or ECP EPP communications respectively Use the defined constants in parxch h to specify these parameters and refer to the installation chapter of this manual for more information about parallel port settings The next five parameters control the ADS1210 A D converter chips by specifying their sampling rate and other basic features Note that all four ADS1210 A D converter chips are initialized and programmed in parallel with the same parameters It is not possible to program an individual ADS1210 with parameters that are different than the others The 27 DLL LIBRARY SUPPORT defined constants in parxch h provide an easily readable way to work with these parameters The parameters are as follows Df stands for data format It maps into the df bit in the ADS1210 control register and controls whether signed integer or unsigned offset data is
42. rate one that reflects your current scope menu settings at any time from the Options menu Refer to the online help and readme txt file for more information about scope and refer to the scope ini initialization file and inisyntx txt for details about its syntax and parameters There is no DOS or Linux version of the scope program since the graphical user interface requires the Microsoft Foundation Class MFC library and must be able to find the MFC DLL files at run time It is assumed that users wanting graphical output will at least be running Windows 95 However for LabView users there is a finished scope like application program written in LabView Refer to the following LabView chapter for more information view This is a Windows GUI program located in the view directory for viewing previously acquired OUT or DAT data files as horizontal traces on the screen You can easily scroll forwards and backwards through the data files There is no DOS or Linux version of this program diag This is a simple diagnostic program that lets you verify your board is functioning correctly It is located in the diags directory and tries several parallel port address and mode combinations to determine which is the best setting for your computer It also allows you to toggle the yellow LED on the PARXCH front panel sample Located in the examples directory sample is a very basic text only program to acquire and display data It shows the essential f
43. sed inputs together To acquire some values and verify the results use the simp or scope programs CONNECTING DIGITAL VO The 15 pin D shell connector on the right hand side of the front of the PARXCH enclosure is for digital input and output Pins 1 4 are for input and pins 5 8 are for output Pins 9 15 are digital ground As with the analog input D shell connector a TRMISE or TRMISV terminal board can be attached to the digital I O D shell connector for simple wire connections Note that the numbers listed along the screw edge of the terminal board are not the same as the D shell pin numbers The terminal board is numbered so that screws 1 2 are pins and 9 etc The yellow LED provides an additional digital output bit that is under program control INSTALLATION INSTALLATION CHECKLIST Plug in the wall transformer and check the green LED on the right hand side of the PARxCH back panel If it is not on the wall transformer is off or otherwise failed Connect the supplied 25 pin D shell cable to your PC parallel port and run the diagnostic program in the diags directory This will show whether the PC s parallel port is correctly connected or not If diag reports an error check your CMOS settings for the correct parallel port mode Also check to be sure the kernel mode device driver is installed for Win2000 XP and Linux Connect analog signals from your source devices to the input pins on the analog input D shell connector on th
44. tion values appropriate for each A D chip before the volts display is accurate To run this demo press the Run Arrow on the toolbar to enable the Driver Name control the Xch Model control the Port Mode switch the Units switch and the Sample Period dial Once these controls are set to their desired values press the green START button to begin acquisition Acquisition will continue until you press the red STOP button to end the demo PARxCH Scope Demo The scope demo samples the PARxCH at a faster rate and displays the results as horizontal waveforms like an oscilloscope In addition both a header file containing information like the channels and sampling rate and a binary data file containing the data points are written out to the LabView default directory that is set from the Edit gt Preferences menu option These files use the same format as those output by the C language programs simp exe and scope exe After the front panel controls have been set the PARxCH is initialized the header file is written and acquisition is started Because the sampling rate for this demo VI is much faster than for PARxCH Demo Meter a buffer worth of samples is allowed to accumulate before they are read from the FIFO instead of reading them one set at a time So Ready is called to determine when one sample is available and Read Data is called repeatedly to read in a buffer worth of samples which are written out and displayed on the multi plot graph To reduce
45. use the LabView Operating tool to set the Port Mode switch and the Port Name value as appropriate for your computer Then press the Run Arrow on the toolbar If PARxCH initialization is successful you can press the Toggle LED button With each press both the yellow LED indicator on the LabView front panel and the physical LED on the board will change state To end the demo press the red STOP button PARxCH Meter Demo This VI samples the PARxCH at a slow rate and displays the results as digital readouts After the front panel controls have been set the PARxCH is initialized and acquisition is started Ready is called to determine when a new sample for each channel is available Then Read 32 LABVIEW SUPPORT Data is called to read them in Since the desired sampling rates are slower than the minimum native rate that can be assigned to the ADS1210 A D converters several adjacent samples are acquired and averaged together before being displayed This additional averaging has the added benefit of improving the resolution of the results The results can be displayed as counts or volts When counts is selected the 24 bits received from the A D converters are displayed as six hex digits When volts is selected the count values are converted to volts by multiplying by a scale factor and adding an offset The scaling factor and offset are computed in the calibration frame using approximate default values but you will require different calibra
46. using so please consult the circuit diagrams and board legend for proper connections The PARxCH is protected with diodes so that it is unlikely incorrectly connected power supplies will damage it However the PARxCH is not protected from excessive overvoltages Connecting either AC or DC power that is badly out of range may damage the board Customers using their own power supplies should be aware that they are responsible INSTALLATION for providing the correct voltages Please read the limited warranty at the beginning of this manual CONNECTING TO THE PC PARALLEL PORT Included with the PARxCH is a 6 ft molded 25 pin D shell cable for connecting to the PC parallel port The female end of this cable should be connected to the D shell connector on the back of the PARxCH while the other end should be connected to the parallel port connector on your PC Do NOT connect the cable to 25 pin RS232 interfaces or to the 25 pin analog inputs on the PAR8CH Only connect to PC parallel ports The PARxCH has been designed to work with IEEE 1284 type EPP BPP parallel ports This type of port has significantly improved performance over the standard Centronics SPP parallel port on the original PC The PARxCH will also work with standard PS2 style bi directional BPP parallel ports found on many computers Most users with PCs manufactured after 1995 will have EPP compatible parallel ports even though they may not realize it To make sure you are running in
47. ut or dat binary data files output by simp and scope into other formats Currently converters are provided for ASCII text and IASPEI SUDS formats Under Linux converters for the Seismic Unix SU format are also provided Additional converters will be added in the future The existing conversion programs can also serve as an example for writing customized converters to your preferred data format 11 DLL LIBRARY SUPPORT LIBRARY FUNCTIONS The library functions are at the core of the software supplied with the SR PARxCH They allow users to control board operation from high level languages without having to know the low level details of how the system operates These functions can be statically linked to C programs for any OS In addition they are available as a Dynamic Link Library DLL under Windows and as a shared library so under Linux When used as a DLL these functions can be called from other high level programming languages such as Microsoft Visual Basic and National Instruments LabView This chapter covers usage from programming environments like Visual C For information about usage from LabView see the LabView chapter For data acquisition applications that are ready to run with no programming required see the Finished Applications chapter The outline of how to use the PARxCH library functions is fairly simple First call the Open function to open the driver and initialize the sampling rate and other parameters Once the board
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