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Product choice support: 6-8 simultaneous channel sampling, 1808X or ???



I have tried asking this question via voicemail, email, and now this forum.

Currently have 4 systems using the analog-in sampling of the USB-2527 to capture waveforms using the APreTrig command.

New application requires a miniumum of 5 simultaneous signals to be sampled, with 2 of them differential. The waveform is roughly pulse-shaped and 500us to 1.5ms wide at the base.

It seems like the USB-1808X-OEM will work. We like the OEM version because it allows us to use the header pins to connect to a logic/glue PCB, similar to how we use the USB-2527. We like the 200kSa/s and the 18-bit may not be required, but the couple of extra bits 


1) Are there other MCC DAQ products could be a better fit?

2) We are using the APreTrig command on the USB-2527, to get o-scope-like waveforms with pre-trigger samples. Is doesn't seem like the USB-1808 supports this command. Is there another way to obtain this behavior?

For reference, here's a snippet of the USB-2527 commands used to capture a waveform from a single channel:


Allocate Memory

        MemHandleforDropPulse = cbWinBufAlloc(NumDropPulsePoints)      ' set aside memory to hold data

' Set the trigger conditions here

    ULStat = cbSetTrigger(USB_2527, TRIGABOVE, LowThresh, HiThresh)

    ' Take the scan here after the trigger conditions are met

    ULStat = cbAPretrig(USB_2527, UUTAccelNum1, UUTAccelNum1, CBPreTrigCount, CBTotalCount, CBRate, BIP5VOLTS,

MemHandleforDropPulse, Options)  //Option = BACKGROUND

    ' We will poll the status bit to see if the background scan has finished

        ErrorCode = cbGetStatus(USB_2527, Status, ScanCount, ScanIndex, AIFUNCTION)

   ' Transfer the data from the memory buffer set up by Windows to an array for use by Visual Basic

        ULStat = cbWinBufToArray(MemHandleforDropPulse, DropPulseData(0), FirstPoint, CBTotalCount)

Free Buffer at end     

        ULStat = cbWinBufFree(MemHandleforDropPulse)     ' Free up memory for use by other programs


Thanks in advance


Edited by SomeguyinSeattle
minor correction, grammar
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The USB-2527 driver, when configured for pretrigger, scans the data, looking for the trigger condition. The feature originated with our PCI boards, which could return data quickly giving the driver adequate time to perform the operation. For the most part, the USB devices lack the pre-trigger functionality because their data bus is relatively slow compared to the PCI bus. Exceptions are the USB-2500 series and the USB-1602HS and USB-1604HS. 

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