CompuScope SDK Manua.. - Egmont Instruments

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CompuScope A/D cards generally operate in two capture modes – single and dual channel modes. In thedual channel mode, the two on-board A/D digitize the analog signals from the two input channels. The firstADC, labeled as ADC 1, digitizes the input analog signal on channel 1 while ADC 2 digitizes the inputanalog signal on channel 2. Both ADCs are synchronized using exactly the same clock signal so that notiming disparity exists between the digitized data from the two ADCs. Sampling is truly simultaneous onboth channels.In the single channel mode, however, the input analog signal is internally connected to both ADCs. Thetwo ADCs are then clocked 180 degrees out of phase. When the acquisition starts, at the first rising edge ofthe clock, the signal from Channel 1 is sampled by ADC1 and the digital data are stored in memory bank 1.The next sample is digitized by the ADC2, whose clock signal is inverted with respect to ADC 1’s clockand the digital data are stored in memory bank 2. This process is then repeated until acquisition iscomplete. This method is referred to as ping- ponging of the ADCs, meaning that both ADCs digitizealternate data points from channel 1. After acquisition, the data from memory banks 1 and 2 areinterleaved to yield a record that was effectively sampled at twice the ADC clocking frequency. This iswhy most CompuScopes in single channel mode can sample at double the maximum rate possible in dualchannel mode.There are two basic methods of acquiring data records using a CompuScope: Single Record Mode andMultiple Record Mode. These are described in the next two sections.Single Record ModeSingle Record Mode is the simplest method of acquiring data records with a CompuScope. In the singlerecord, a CompuScope card digitizes the analog signal on one or two channels. The digitized data arestored in the on-board memory of the CompuScope card. The data are then downloaded to PC memory forpost-processing after the acquisition ends. The card is now ready for next acquisition. The time taken tocapture and download a record, is dependent primarily on the size of the record captured and on bus datatransfer speed.In Single Record Mode, the CompuScope is able to capture both pre and post trigger data points in eithersingle or dual channel mode. For single channel capture, the entire memory depth can be used for thecaptured record. . For dual channel capture, the memory must be shared between both channels so that themaximum capture length is one half of the total on-board memory.It is straightforward to understand that the time taken by the CompuScope to get ready for next acquisitionincreases with the length of the captured record. Thus the single record mode may not be the best methodfor capturing signals whose triggers repeat at a high rate. Gage CompuScopes have a unique feature calledMultiple Record, which allows capture of successive records in the on-board memory for fast trigger rateapplications. A detailed explanation of Multiple Record feature for the CompuScope cards is provided inthe next section.Multiple RecordIf a signal trigger repeats very quickly, there may not be enough time to transfer the captured data to PCmemory before the next trigger occurs. For such fast trigger requirements, Gage CompuScopes can beoperated in Multiple Record Mode.In Multiple Record Mode, successive acquisitions are stacked in the CompuScope’s on-board memory.Between successive acquisitions, the CompuScope re-arms itself to await the next trigger with no CPUinteraction required. This hardware re-arm typically takes place in under 16 sample points, which isusually well under 1 microsecond for the higher sampling rates.Page 8CompuScope SDK Manual
Multiple Record capture can continue until the CompuScope memory is full. So, for instance, aCompuScope with 1 MegaSamples of on-board memory can capture up to 1000 records of 1000 pointseach.Please note that no pre-trigger data are acquired in Multiple Record Mode.The diagram below shows a typical repetitive signal. The figure also shows the contents of CompuScopememory if the signal were to be acquired in Multiple Record Mode.Master/Slave Multi-Card SystemsOne of the most unique features of the CompuScope cards is the Multi-Card system that can be configured.A Multi-Card system, consisting of one Master and multiple Slave CompuScopes, can be ordered from thefactory if the user wants to capture more than two channels with a common clock and trigger. EachCompuScope in the system must be of the same model number and memory size. Sampling and triggeringis always simultaneous in a Master/Slave CompuScope system.A board-to-board interconnect is supplied with a Master/Slave CompuScope system. This interconnectscarries all the timing signals required for proper inter-CompuScope synchronization. Gage’s proprietaryrigid bridgeboard technology ensures proper distribution of the sampling clock and trigger signal from theMaster CompuScope to all the Slave CompuScopes.The CompuScope Windows drivers are built to naturally support a single Master/Slave CompuScopesystem. GageScope ® , the World’s Most Powerful Oscilloscope Software, can display up to 32 channelsfrom all boards in a CompuScope Master/Slave system on the same screen. The C/C++ SDK containsexplicit sample programs for Master/Slave CompuScope systems.Multiple Independent Multi-Card SystemsIndependent CompuScope cards of different types and memory sizes can be operated within the samecomputer chassis. Such a configuration is referred to as a Multiple Independent Multi-Card system ofCompuScopes. Each CompuScope can be operated with a different sampling rate, trigger source, inputrange etc.A Multiple Independent CompuScopes system is useful for experiments where signals of a different naturemust be acquired. For instance, a user might have to acquire high speed raw RF communication signalswith a CompuScope 82G and at the same time acquire lower speed demodulated audio signals with aCompuScope CS1610.The CompuScope Windows drivers are able to support a single Multiple Independent CompuScope system.GageScope ® supports Multiple Independent systems and displays the signals from each CompuScope in aseparate display Window. The C/C++ SDK contains explicit sample programs for Multiple IndependentCompuScopes system.CompuScope SDK Manual Page 9
Page 1 and 2: Volume I:CompuScope C/C++Software D
Page 3 and 4: Gage Applied Technologies, Inc. Sof
Page 5: Global Table of ContentsVolume I Co
Page 8 and 9: Chapter 5: Sample ProgramsWindows S
Page 11 and 12: PrefaceImportant Notes:• The Comp
Page 13: Chapter 2: BasicCompuScopeOperation
Page 18 and 19: Multiple CompuScope SystemsThe Comp
Page 20 and 21: Plug-n-Play is an inherent part of
Page 22 and 23: On-Board MemoryOrganization of theC
Page 24 and 25: memory counter overflow rolls over
Page 26 and 27: If during the data acquisition the
Page 28 and 29: On-board Memory: A Programmer’s V
Page 30 and 31: CompuScope RepetitiveCapture Perfor
Page 32 and 33: depth portion of the single channel
Page 34 and 35: Page 26CompuScope SDK Manual
Page 36 and 37: Sample Programs Folder Structure us
Page 38 and 39: • Gage_drv.hGage_drv.h contains g
Page 41 and 42: Writing a C Application forCompuSco
Page 43 and 44: The last routine, gage_trigger_cont
Page 45: Chapter 5:Sample Programs
Page 48 and 49: Program NameA2D_PAGED_TRANSFER.EXED
Page 50 and 51: Flow Chart describing the sample pr
Page 52 and 53: gage_trigger_control_2:gage_set_ext
Page 54 and 55: GAG2A2D_MUL_BM.EXEThe sample progra
Page 56 and 57: Gage API routines used:gage_get_dri
Page 58 and 59: DIGITAL_INPUT.EXEThe sample program
Page 61: Chapter 6:Appendices
Page 64 and 65: uInt32 sample_rate;void far *memptr
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trigger_level level at which trigge
Page 68 and 69:
trigger_sensitivitytrigger_bandwidt
Page 70 and 71:
Settings for boarddef structure fie
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10 KHz SRTI_10_KHZ5 KHz SRTI_5_KHZ2
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• couple_eThe parameter couple_e
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Example:Below is illustrated a typi
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Appendix C: CompilingCompuScope SDK
Page 81:
Creating a new LabWindows CVI proje
Page 84 and 85:
Arbitrary Waveform GenerationOne co
Page 86 and 87:
Technical SupportGage Applied Techn
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