Streaming rate

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I am using UE9 to stream data from one analog and 5 digital ports using USB 2.0. Somehow, the acquisition rate is not same as I expect. I am sure that the computer is not an issue. The scanning frequency rate meets dead end at 3000. Here is the code:

Device.LabJack.AddRequest(Var.d_number,"LJ_ioPUT_CONFIG","LJ_chSTREAM_SCAN_FREQUENCY",10000,0,0) // Set Scan Rate: 10000 samples/sec

Device.LabJack.AddRequest(Var.d_number,"LJ_ioPUT_CONFIG","LJ_chSTREAM_BUFFER_SIZE",100000,0,0) //Give the UD driver a 5 second buffer (scanRate * 2 channels * 5 seconds)

Device.LabJack.AddRequest(Var.d_number,"LJ_chSTREAM_WAIT_MODE","LJ_swSLEEP", 0, 0) //Configure reads to wait and retrieve the desired amount of data.


Device.LabJack.AddRequest(Var.d_number,"LJ_ioADD_STREAM_CHANNEL",0,0,0,0) // Add four streaming channels

Device.LabJack.AddRequest(Var.d_number,"LJ_ioGET_DIGITAL_PORT_DIR",193,0,0,0) // Set FIO-port to input

Device.LabJack.AddRequest(Var.d_number,"LJ_ioADD_STREAM_CHANNEL",193,0,0,0) // Add a FIO to streaming channel

Device.LabJack.AddRequest(Var.d_number,"LJ_ioSTART_STREAM",0,0,0,0) // Start Stream Request


Any suggestions?

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What exactly is the symptom you are seeing. Does it stream at all with those commands?

Try setting the analog input resolution to 12.

Note that your request using LJ_ioGET_DIGITAL_PORT_DIR with Channel=193 is not valid. Even if you had a valid channel number, that command does not configure the direction of lines, but rather just reads the direction of lines. What you want to do is use LJ_ioGET_DIGITAL_PORT where Channel is the starting bit numer and x1 is the number of bits to read. So if you want to set all digital lines to input, use Channel=0 and x1=23.

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